From nobody Mon Aug 14 11:29:57 2017 Return-Path: X-Original-To: its@ietf.org Delivered-To: its@ietfa.amsl.com Received: from ietfa.amsl.com (localhost [IPv6:::1]) by ietfa.amsl.com (Postfix) with ESMTP id 23C9C132399; Mon, 14 Aug 2017 11:29:55 -0700 (PDT) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit From: IETF Meeting Session Request Tool To: Cc: suresh.krishnan@gmail.com, housley@vigilsec.com, its@ietf.org, ipwave-chairs@ietf.org X-Test-IDTracker: no X-IETF-IDTracker: 6.58.0 Auto-Submitted: auto-generated Precedence: bulk Message-ID: <150273539505.441.4851693269869198972.idtracker@ietfa.amsl.com> Date: Mon, 14 Aug 2017 11:29:55 -0700 Archived-At: Subject: [ipwave] ipwave - New Meeting Session Request for IETF 100 X-BeenThere: its@ietf.org X-Mailman-Version: 2.1.22 List-Id: IPWAVE - IP Wireless Access in Vehicular Environments WG at IETF List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Aug 2017 18:29:55 -0000 A new meeting session request has just been submitted by Russ Housley, a Chair of the ipwave working group. --------------------------------------------------------- Working Group Name: IP Wireless Access in Vehicular Environments Area Name: Internet Area Session Requester: Russ Housley Number of Sessions: 1 Length of Session(s): 1 Hour Number of Attendees: 100 Conflicts to Avoid: First Priority: l2sm saag rtgarea manet 6man 6lo intarea fud stir lamps nfvrg detnet Second Priority: sfc cfrg dhc roll ospf i2nsf isis lime dmm Third Priority: mtgvenue iasa20 People who must be present: Russ Housley Suresh Krishnan Carlos J. Bernardos Resources Requested: Special Requests: --------------------------------------------------------- From nobody Fri Aug 18 08:40:23 2017 Return-Path: X-Original-To: its@ietf.org Delivered-To: its@ietfa.amsl.com Received: from ietfa.amsl.com (localhost [IPv6:::1]) by ietfa.amsl.com (Postfix) with ESMTP id 2113A1329AF; Fri, 18 Aug 2017 08:40:15 -0700 (PDT) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit From: internet-drafts@ietf.org To: Cc: its@ietf.org X-Test-IDTracker: no X-IETF-IDTracker: 6.58.0 Auto-Submitted: auto-generated Precedence: bulk Message-ID: <150307081500.14196.2111291351079489748@ietfa.amsl.com> Date: Fri, 18 Aug 2017 08:40:15 -0700 Archived-At: Subject: [ipwave] I-D Action: draft-ietf-ipwave-ipv6-over-80211ocb-04.txt X-BeenThere: its@ietf.org X-Mailman-Version: 2.1.22 List-Id: IPWAVE - IP Wireless Access in Vehicular Environments WG at IETF List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Aug 2017 15:40:15 -0000 A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the IP Wireless Access in Vehicular Environments WG of the IETF. Title : Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside the Context of a Basic Service Set (IPv6-over-80211ocb) Authors : Alexandre Petrescu Nabil Benamar Jérôme Härri Christian Huitema Jong-Hyouk Lee Thierry Ernst Tony Li Filename : draft-ietf-ipwave-ipv6-over-80211ocb-04.txt Pages : 34 Date : 2017-08-17 Abstract: In order to transmit IPv6 packets on IEEE 802.11 networks run outside the context of a basic service set (OCB, earlier "802.11p") there is a need to define a few parameters such as the recommended Maximum Transmission Unit size, the header format preceding the IPv6 header, the Type value within it, and others. This document describes these parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the layering of IPv6 on 802.11 OCB similarly to other known 802.11 and Ethernet layers - by using an Ethernet Adaptation Layer. In addition, the document attempts to list what is different in 802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n layers, layers over which IPv6 protocols operates without issues. Most notably, the operation outside the context of a BSS (OCB) has impact on IPv6 handover behaviour and on IPv6 security. An example of an IPv6 packet captured while transmitted over an IEEE 802.11 OCB link (802.11p) is given. The IETF datatracker status page for this draft is: https://datatracker.ietf.org/doc/draft-ietf-ipwave-ipv6-over-80211ocb/ There are also htmlized versions available at: https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04 https://datatracker.ietf.org/doc/html/draft-ietf-ipwave-ipv6-over-80211ocb-04 A diff from the previous version is available at: https://www.ietf.org/rfcdiff?url2=draft-ietf-ipwave-ipv6-over-80211ocb-04 Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at tools.ietf.org. Internet-Drafts are also available by anonymous FTP at: ftp://ftp.ietf.org/internet-drafts/ From nobody Mon Aug 21 08:14:45 2017 Return-Path: X-Original-To: its@ietfa.amsl.com Delivered-To: its@ietfa.amsl.com Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 0CCD7132A66 for ; Mon, 21 Aug 2017 08:14:44 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -4.19 X-Spam-Level: X-Spam-Status: No, score=-4.19 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, T_REMOTE_IMAGE=0.01] autolearn=ham autolearn_force=no Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Lm6siB8Amxbn for ; Mon, 21 Aug 2017 08:14:40 -0700 (PDT) Received: from mail.cec.uchile.cl (mail1.cec.uchile.cl [200.9.100.12]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 66FA3132650 for ; Mon, 21 Aug 2017 08:14:36 -0700 (PDT) Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.cec.uchile.cl (Postfix) with ESMTP id DD2DB3473F0 for ; Mon, 21 Aug 2017 12:14:33 -0300 (-03) X-Virus-Scanned: by amavisd-new at ing.uchile.cl Received: from mail.cec.uchile.cl ([127.0.0.1]) by localhost (mail1.cec.uchile.cl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id lNMbk6QWsmT0 for ; Mon, 21 Aug 2017 12:14:33 -0300 (-03) Received: from [172.17.29.7] (unknown [172.17.29.7]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (Client did not present a certificate) by mail.cec.uchile.cl (Postfix) with ESMTP id 917763473EC for ; Mon, 21 Aug 2017 12:14:33 -0300 (-03) To: its@ietf.org References: <150307081500.14196.2111291351079489748@ietfa.amsl.com> From: =?UTF-8?Q?Sandra_C=c3=a9spedes_U.?= Message-ID: <6f4dfdfc-e092-f610-40d6-58ddcff00299@ing.uchile.cl> Date: Mon, 21 Aug 2017 12:14:33 -0300 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <150307081500.14196.2111291351079489748@ietfa.amsl.com> Content-Type: multipart/alternative; boundary="------------9B82CE5775D1615FBFF0DB8F" Content-Language: en-US X-Antivirus: Avast (VPS 170821-4, 21-08-2017), Outbound message X-Antivirus-Status: Clean Archived-At: Subject: [ipwave] Comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt X-BeenThere: its@ietf.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: IPWAVE - IP Wireless Access in Vehicular Environments WG at IETF List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Aug 2017 15:14:44 -0000 This is a multi-part message in MIME format. --------------9B82CE5775D1615FBFF0DB8F Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Hello Hera are my comments on draft-ietf-ipwave-ipv6-over-80211ocb-04: 1. I suggest to choose only one way to address the 802.11 technology in the document. You have 802.11-OCB, 802.11 OCB, 802.11-2012 OCB, IEEE 802.11 OCB, and 802.11p. At some point it is mentioned that "In the following text we use the term "802.11p" to mean 802.11-2012 OCB." However, in the next paragraph it goes back to 802.11 OCB, so it seems inconsistent. 2. In page 4, suggest to change "These points are consequences of the OCB operation which is particular to 802.11 OCB (Outside the Context of a BSS)" for "These points are consequences of the Outside the Context of a BSS operation which is particular to 802.11 OCB". 3. In page 4, there seems to be a contradiction. In the first paragraph is mentioned that "while there is no encryption applied below the network layer using 802.11p, 1609.2 [ieee1609.2] does provide security services for applications to use so that there can easily be data security over the air without invoking IPsec." However, in the fifth paragraph is mentioned that "the IP security mechanisms are necessary, since OCB means that 802.11 is stripped of all 802.11 link-layer security;". I understood that IPSec wasn't necessary but the last phrase seems to say the opposite. Am I wrong? 4. In page 7, suggest to change "(IPv6 is layered on top of LLC on top of 802.11 OCB similarly as on top of LLC on top of 802.11a/b/g/n, and as on top of LLC on top of 802.3)" to "(IPv6 is layered on top of LLC on top of 802.11 OCB, in the same way that IPv6 is layered on top of LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on top of 802.3 (for Ethernet))". 5. In page 7, suggest to change "This band is "5.9GHz" which is different from the bands "2.4GHz" or "5GHz" used by Wireless LAN" to "The 5.9GHz band is different from the 2.4GHz and 5GHz bands used by Wireless LAN". Same suggestion to other appearances in the same paragraph. 6. In page 7 you mention " In the list below, the only 802.11 OCB fundamental points which influence IPv6 are the OCB operation and the 12Mbit/s maximum which may be afforded by the IPv6 applications." I found the description for OCB operation but none for the 12Mbit/s maximum (not sure if you are referring to a maximum data rate? I thought it was actually 27 Mbps), so it is not clear how the second "fundamental point" influences the operation of IPv6. 7. In Appendix C.1, perhaps it should be mentioned that relaying on an identifier obtained from the MAC address might not be possible not only in the presence of multiple 802.11-OCB NICs, but also if there is randomization of MAC addresses. 8. Appendix C.2 defines several MUSTs for authentication, time synchronization, etc. Why is this defined as an appendix and not in the main document? Typos: Abstract: - layers over which IPv6 protocols operates --> layers over which IPV6 protocols operate Introduction: - Such a station, when it has the flag set, it uses --> Such a station, when it has the flag set, uses Terminology: - OCB: outside the context of a basic service set (BSS): --> OCB (Outside the context of a Basic Service Set - BSS): Page 6: -Note that in earlier 802.11p documents the term "OCBEnabled" was used instead of te current "OCBActivated". --> Note that in earlier 802.11p documents the term "OCBEnabled" was used instead of the current "OCBActivated". Page 10: - The Equivalent Transmit Time on Channel --> The Equivalent Transmit Time on Channel (ETTC) Page 18: -In the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 which is he corresponding multicast MAC address. --> In the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 which is the corresponding multicast MAC address. Page 29: -However, the high mobility,strong link asymetry --> However, the high mobility, strong link asymmetry - Automotive networks require the unique representation of each of their node --> Automotive networks require the unique representation of each node - IEEE 802.11-OCB link MUST support strong link asymetry --> IEEE 802.11-OCB link MUST support strong link asymmetry Regards, Sandra Céspedes -- Sandra L. Céspedes, Ph.D. | Assistant Professor Department of Electrical Engineering Universidad de Chile Av. Tupper 2007, Santiago, Chile. 8370451 Tel. +56 (2) 29784093 | Of. 504 URL:http://www.cec.uchile.cl/~scespedes On 18-08-2017 12:40, internet-drafts@ietf.org wrote: > A New Internet-Draft is available from the on-line Internet-Drafts directories. > This draft is a work item of the IP Wireless Access in Vehicular Environments WG of the IETF. > > Title : Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside the Context of a Basic Service Set (IPv6-over-80211ocb) > Authors : Alexandre Petrescu > Nabil Benamar > Jérôme Härri > Christian Huitema > Jong-Hyouk Lee > Thierry Ernst > Tony Li > Filename : draft-ietf-ipwave-ipv6-over-80211ocb-04.txt > Pages : 34 > Date : 2017-08-17 > > Abstract: > In order to transmit IPv6 packets on IEEE 802.11 networks run outside > the context of a basic service set (OCB, earlier "802.11p") there is > a need to define a few parameters such as the recommended Maximum > Transmission Unit size, the header format preceding the IPv6 header, > the Type value within it, and others. This document describes these > parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the > layering of IPv6 on 802.11 OCB similarly to other known 802.11 and > Ethernet layers - by using an Ethernet Adaptation Layer. > > In addition, the document attempts to list what is different in > 802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n > layers, layers over which IPv6 protocols operates without issues. > Most notably, the operation outside the context of a BSS (OCB) has > impact on IPv6 handover behaviour and on IPv6 security. > > An example of an IPv6 packet captured while transmitted over an IEEE > 802.11 OCB link (802.11p) is given. > > > The IETF datatracker status page for this draft is: > https://datatracker.ietf.org/doc/draft-ietf-ipwave-ipv6-over-80211ocb/ > > There are also htmlized versions available at: > https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04 > https://datatracker.ietf.org/doc/html/draft-ietf-ipwave-ipv6-over-80211ocb-04 > > A diff from the previous version is available at: > https://www.ietf.org/rfcdiff?url2=draft-ietf-ipwave-ipv6-over-80211ocb-04 > > > Please note that it may take a couple of minutes from the time of submission > until the htmlized version and diff are available at tools.ietf.org. > > Internet-Drafts are also available by anonymous FTP at: > ftp://ftp.ietf.org/internet-drafts/ > > _______________________________________________ > its mailing list > its@ietf.org > https://www.ietf.org/mailman/listinfo/its --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus --------------9B82CE5775D1615FBFF0DB8F Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit

Hello

Hera are my comments on draft-ietf-ipwave-ipv6-over-80211ocb-04:

  1. I suggest to choose only one way to address the 802.11 technology in the document. You have 802.11-OCB, 802.11 OCB, 802.11-2012 OCB, IEEE 802.11 OCB, and 802.11p. At some point it is mentioned that "In the following text we use the term "802.11p" to mean 802.11-2012 OCB." However, in the next  paragraph it goes back to 802.11 OCB, so it seems inconsistent.
  2. In page 4, suggest to change "These points are consequences of the OCB operation which is particular to 802.11 OCB (Outside the Context of a BSS)" for "These points are consequences of the Outside the Context of a BSS operation which is particular to 802.11 OCB".
  3. In page 4, there seems to be a contradiction. In the first paragraph is mentioned that "while there is no encryption applied below the network  layer using 802.11p, 1609.2 [ieee1609.2] does provide security services for applications to use so that there can easily be data security over the air without invoking IPsec." However, in the fifth paragraph is mentioned that "the IP security mechanisms are necessary, since OCB means that 802.11 is stripped of all 802.11 link-layer security;".  I understood that IPSec wasn't necessary but the last phrase seems to say the opposite. Am I wrong?
  4. In page 7, suggest to change "(IPv6 is layered on top of LLC on top of 802.11 OCB similarly as on top of LLC on top of 802.11a/b/g/n, and as on top of LLC on top of 802.3)" to "(IPv6 is layered on top of LLC on top of 802.11 OCB, in the same way that IPv6 is layered on top of LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on top of 802.3 (for Ethernet))".
  5. In page 7, suggest to change "This band is "5.9GHz" which is different from the bands "2.4GHz" or "5GHz" used by Wireless LAN" to "The 5.9GHz band is different from the 2.4GHz and 5GHz bands used by Wireless LAN".  Same suggestion to other appearances in the same paragraph.
  6. In page 7 you mention " In the list below, the only 802.11 OCB fundamental points which influence IPv6 are the OCB operation and the 12Mbit/s maximum which may be afforded by the IPv6 applications."  I found the description for OCB operation but none for the 12Mbit/s maximum (not sure if you are referring to a maximum data rate? I thought it was actually 27 Mbps), so it is not clear how the second "fundamental point" influences the operation of IPv6.
  7. In Appendix C.1, perhaps it should be mentioned that relaying on an identifier obtained from the MAC address might not be possible not only in the presence of multiple 802.11-OCB NICs, but also if there is randomization of MAC addresses.
  8. Appendix C.2 defines several MUSTs for authentication, time synchronization, etc. Why is this defined as an appendix and not in the main document?

Typos:

Abstract:
- layers over which IPv6 protocols operates --> layers over which IPV6 protocols operate
Introduction:
- Such a station, when it has the flag set, it uses --> Such a station, when it has the flag set, uses
Terminology:
-  OCB: outside the context of a basic service set (BSS): --> OCB (Outside the context of a Basic Service Set - BSS):
Page 6:
-Note that in earlier 802.11p documents the term "OCBEnabled" was used instead of te current "OCBActivated". --> Note that in earlier 802.11p documents the term "OCBEnabled" was used instead of the current "OCBActivated".
Page 10:
- The Equivalent Transmit Time on Channel --> The Equivalent Transmit Time on Channel  (ETTC)
Page 18:
-In the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
   which is he corresponding multicast MAC address. --> In
   the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
   which is the corresponding multicast MAC address.
Page 29:
-However, the high mobility,strong link asymetry --> However, the high mobility,
   strong link asymmetry
- Automotive networks require the unique representation of each of
   their node -->  Automotive networks require the unique representation of each node
- IEEE 802.11-OCB link MUST support strong link asymetry --> IEEE 802.11-OCB link MUST support strong link asymmetry

Regards,

Sandra Céspedes


-- 
Sandra L. Céspedes, Ph.D. | Assistant Professor
Department of Electrical Engineering
Universidad de Chile
Av. Tupper 2007, Santiago, Chile. 8370451
Tel. +56 (2) 29784093 | Of. 504
URL: http://www.cec.uchile.cl/~scespedes
On 18-08-2017 12:40, internet-drafts@ietf.org wrote:
A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the IP Wireless Access in Vehicular Environments WG of the IETF.

        Title           : Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside the Context of a Basic Service Set (IPv6-over-80211ocb)
        Authors         : Alexandre Petrescu
                          Nabil Benamar
                          Jérôme Härri
                          Christian Huitema
                          Jong-Hyouk Lee
                          Thierry Ernst
                          Tony Li
	Filename        : draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
	Pages           : 34
	Date            : 2017-08-17

Abstract:
   In order to transmit IPv6 packets on IEEE 802.11 networks run outside
   the context of a basic service set (OCB, earlier "802.11p") there is
   a need to define a few parameters such as the recommended Maximum
   Transmission Unit size, the header format preceding the IPv6 header,
   the Type value within it, and others.  This document describes these
   parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
   layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
   Ethernet layers - by using an Ethernet Adaptation Layer.

   In addition, the document attempts to list what is different in
   802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
   layers, layers over which IPv6 protocols operates without issues.
   Most notably, the operation outside the context of a BSS (OCB) has
   impact on IPv6 handover behaviour and on IPv6 security.

   An example of an IPv6 packet captured while transmitted over an IEEE
   802.11 OCB link (802.11p) is given.


The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-ipwave-ipv6-over-80211ocb/

There are also htmlized versions available at:
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04
https://datatracker.ietf.org/doc/html/draft-ietf-ipwave-ipv6-over-80211ocb-04

A diff from the previous version is available at:
https://www.ietf.org/rfcdiff?url2=draft-ietf-ipwave-ipv6-over-80211ocb-04


Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

_______________________________________________
its mailing list
its@ietf.org
https://www.ietf.org/mailman/listinfo/its



  




	

        
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Thread-Topic: Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
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Attached is my review feedback.

In general there is lot of good information in the document. But, there are=
 also few areas where additional clarifications will greatly help.

1.) Its not clear, if the document makes any assumption on the operating en=
vironment/communication profile. There is not much discussion on that aspec=
t; For example, Is it always a one-hop communication between RSU and OBU wh=
ere the 802.11-OCB link?  So, is the use of IPv6 only in that context of 1-=
hop communication?

2.) There is also no discussion on how these links get formed in vehicular =
environment and when they are attached/detached.

3.) How do nodes discover each other?  How does ND resolution work? Are the=
se messages received by a multiple RSU=92s, or a single RSU? Whats the impl=
ication of that. Note that you don=92t have that issue in 802.11, given the=
 association to an access point, which in turn maps the links to a VLAN/sub=
net.

4.) What happens as a vehicle moves between RSU=92s, how does it impact add=
ress configuration?   Is DHCPv6 based address configuration relevant here?


 Please see inline for additional comments.




------------------------------------------------------------------


Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside


the Context of a Basic Service Set (IPv6-over-80211ocb)


draft-ietf-ipwave-ipv6-over-80211ocb-04.txt




[Sri] May be change to, =93..in mode .." =97> =93..operating in mode ..=94 =
 ?



Abstract

   In order to transmit IPv6 packets on IEEE 802.11 networks run outside
   the context of a basic service set (OCB, earlier "802.11p") there is
   a need to define a few parameters such as the recommended Maximum
   Transmission Unit size, the header format preceding the IPv6 header,
   the Type value within it, and others.  This document describes these
   parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
   layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
   Ethernet layers - by using an Ethernet Adaptation Layer.


[Sri] Is it =93recommended MTU size", or "supported MTU size on the 802.11 =
OCB link?



   In addition, the document attempts to list what is different in
   802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
   layers, layers over which IPv6 protocols operates without issues.
   Most notably, the operation outside the context of a BSS (OCB) has
   impact on IPv6 handover behaviour and on IPv6 security.


[Sri] Minor comment. May be instead of using the =93layer=94 terminology, y=
ou may want to present this as IPv6 support on "802.11 OCB" links.


   An example of an IPv6 packet captured while transmitted over an IEEE
   802.11 OCB link (802.11p) is given.


[Sri] Last paragraph can be ommitted in my view. That=92s too much of detai=
l for Abstract.


Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute



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   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 18, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 an=
d the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   =
3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   =
5
   3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    6
   4.  Aspects introduced by the OCB mode to 802.11  . . . . . . . .   =
6
   5.  Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . .  1=
0
     5.1.  Maximum Transmission Unit (MTU) . . . . . . . . . . . . . =
 10
     5.2.  Frame Format  . . . . . . . . . . . . . . . . . . . . . . =
 11
       5.2.1.  Ethernet Adaptation Layer . . . . . . . . . . . . . =
.  12
     5.3.  Link-Local Addresses  . . . . . . . . . . . . . . . . . . =
 13
     5.4.  Address Mapping . . . . . . . . . . . . . . . . . . . . . =
 14
       5.4.1.  Address Mapping -- Unicast  . . . . . . . . . . . . =
.  14
       5.4.2.  Address Mapping -- Multicast  . . . . . . . . . . . =
.  14
     5.5.  Stateless Autoconfiguration . . . . . . . . . . . . . . . =
 15
     5.6.  Subnet Structure  . . . . . . . . . . . . . . . . . . . . =
 16
   6.  Example IPv6 Packet captured over a IEEE 802.11-OCB link  . .  1=
6
     6.1.  Capture in Monitor Mode . . . . . . . . . . . . . . . . . =
 17
     6.2.  Capture in Normal Mode  . . . . . . . . . . . . . . . . . =
 19
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  2=
1
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  2=
2
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  2=
2
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  =
22



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   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  =
23
     11.1.  Normative References . . . . . . . . . . . . . . . . . .=
  23
     11.2.  Informative References . . . . . . . . . . . . . . . . .=
  24
   Appendix A.  ChangeLog  . . . . . . . . . . . . . . . . . . . . .  =
26
   Appendix B.  Changes Needed on a software driver 802.11a to
                become a                     802.11-OCB driver . . .  28
   Appendix C.  Design Considerations  . . . . . . . . . . . . . . .  =
30
     C.1.  Vehicle ID  . . . . . . . . . . . . . . . . . . . . . . .=
  30
     C.2.  Reliability Requirements  . . . . . . . . . . . . . . . .=
  30
     C.3.  Multiple interfaces . . . . . . . . . . . . . . . . . . .=
  31
     C.4.  MAC Address Generation  . . . . . . . . . . . . . . . . .=
  32
   Appendix D.  IEEE 802.11 Messages Transmitted in OCB mode . . . .  =
32
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  32


1.  Introduction


   This document describes the transmission of IPv6 packets on IEEE Std
   802.11 OCB networks (earlier known as 802.11p).


[Sri] Please add a reference to the IEEE specification that defines the OCB=
 mode.



This involves the
   layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with
   an LLC layer).  Compared to running IPv6 over the Ethernet MAC layer,
   there is no modification required to the standards: IPv6 works fine
   directly over 802.11 OCB too (with an LLC layer).

   The term "802.11p" is an earlier definition.  As of year 2012, the
   behaviour of "802.11p" networks has been rolled in the document IEEE
   Std 802.11-2012.  In this document the term 802.11p disappears.
   Instead, each 802.11p feature is conditioned by a flag in the
   Management Information Base.  That flag is named "OCBActivated".
   Whenever OCBActivated is set to true the feature it relates to
   represents an earlier 802.11p feature.  For example, an 802.11
   STAtion operating outside the context of a basic service set has the
   OCBActivated flag set.  Such a station, when it has the flag set, it
   uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.

   In the following text we use the term "802.11p" to mean 802.11-2012
   OCB.

   The IPv6 network layer operates on 802.11 OCB in the same manner as
   it operates on 802.11 WiFi, with a few particular exceptions.  The
   IPv6 network layer operates on WiFi by involving an Ethernet
   Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers
   to Ethernet II headers.  The operation of IP on Ethernet is described
   in [RFC1042] and [RFC2464].  The situation of IPv6 networking layer
   on Ethernet Adaptation Layer is illustrated below:







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                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |                 IPv6                  |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |       Ethernet Adaptation Layer       |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi MAC           |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi PHY           |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   (in the above figure, a WiFi profile is represented; this is used
   also for OCB profile.)

   A more theoretical and detailed view of layer stacking, and
   interfaces between the IP layer and 802.11 OCB layers, is illustrated
   below.  The IP layer operates on top of the EtherType Protocol
   Discrimination (EPD); this Discrimination layer is described in IEEE
   Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP
   (Link Layer Control Service Accesss Point).


           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           |                 IPv6                  |
           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+
                       {   LLC_SAP  }                 802.11 OCB
           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+  Boundary
           |            EPD          |       |     |
           |                         | MLME  |     |
           +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   |
           |      MAC Sublayer       |       |     |  802.11 OCB
           |     and ch. coord.      |       | SME |  Services
           +-+-+-{   PHY_SAP  }+-+-+-+-+-+-+-|     |
           |                         | PLME  |     |
           |            PHY Layer    |   PLME_SAP  |
           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   In addition to the description of interface between IP and MAC using
   "Ethernet Adaptation Layer" and "Ethernet Protocol Discrimination
   (EPD)" it is worth mentioning that SNAP [RFC1042] is used to carry
   the IPv6 Ethertype.

   However, there may be some deployment considerations helping optimize
   the performances of running IPv6 over 802.11-OCB (e.g. in the case of
   handovers between 802.11 OCB-enabled access routers, or the
   consideration of using the IP security layer [RFC4301]).




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   There are currently no specifications for handover between OCB links
   since these are currently specified as LLC-1 links (i.e.
   connectionless).  Any handovers must be performed above the Data Link
   Layer.  Also, while there is no encryption applied below the network
   layer using 802.11p, 1609.2 [ieee1609.2] does provide security
   services for applications to use so that there can easily be data
   security over the air without invoking IPsec.

   We briefly introduce the vehicular communication scenarios where IEEE
   802.11-OCB links are used.


[Sri] I have not seen much discussion on the link / communication assumptio=
ns.



 This is followed by a description of
   differences in specification terms, between 802.11 OCB and
   802.11a/b/g/n (and the same differences expressed in terms of
   requirements to software implementation are listed in Appendix B.)

   The document then concentrates on the parameters of layering IP over
   802.11 OCB as over Ethernet: value of MTU, the contents of Frame
   Format, the rules for forming Interface Identifiers, the mechanism
   for Address Mapping and for State-less Address Auto-configuration.
   These are precisely the same as IPv6 over Ethernet [RFC2464].

   As an example, these characteristics of layering IPv6 straight over
   LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet
   captured over a 802.11 OCB link; this is described in the section
   Section 6.

   A couple of points can be considered as different, although they are
   not required in order to have a working implementation of IPv6-over-
   802.11-OCB.  These points are consequences of the OCB operation which
   is particular to 802.11 OCB (Outside the Context of a BSS).  First,
   the handovers between OCB links need specific behaviour for IP Router
   Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of
   higher layer messages such as the 'Basic Safety Message' (in the US)
   or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE
   Routing Advertisement'; second, the IP security mechanisms are
   necessary, since OCB means that 802.11 is stripped of all 802.11
   link-layer security; a small additional security aspect which is
   shared between 802.11 OCB and other 802.11 links is the privacy
   concerns related to the address formation mechanisms.

   In the published literature, many documents describe aspects related
   to running IPv6 over 802.11 OCB:
   [I-D.jeong-ipwave-vehicular-networking-survey].


2.  Terminology


   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].



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   RSU: Road Side Unit.  A computer equipped with at least one IEEE
   802.11 interface operated in OCB mode.  This definition applies to
   this document.  An RSU may be connected to the Internet, and may be
   equipped with additional wired or wireless network interfaces running
   IP.  An RSU MAY be an IP Router.



[Sri] RSU can be compared to an 802.11 access point; Or, WTP as defined in =
CAPWAP specification, RFC5415.


Perhaps. rephrase as below?:


"RSU: Road Side Unit. Its a wireless termination point (WTP), as defined in=
 RFC5415 with one key difference, where the wireless physical and the mac l=
ayer is configured to operate in 802.11 OCB mode.  The RSU communicates wit=
h the On board Unit (OBU) in the vehicle over 802.11 wireless link operatin=
g in OCB mode.=94



** Also, since you are defining the RSU term, should you also not define OB=
U (On board Unit) in the vehicle which is the entity on the other end of th=
e link? =93RSU ----802.11-OCB=97=97OBU=94 ? May be introduce the OCB defini=
tion separately, just as you did with RSU, and show the communication link =
as 802.11-OCB.



   OCB: outside the context of a basic service set (BSS): A mode of
   operation in which a STA is not a member of a BSS and does not
   utilize IEEE Std 802.11 authentication, association, or data
   confidentiality.

   802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is
   flagged by "dot11OCBActivated".  This means: IEEE 802.11e for quality
   of service; 802.11j-2004 for half-clocked operations; and (what was
   known earlier as) 802.11p for operation in the 5.9 GHz band and in
   mode OCB.



[Sri] The text starting with. =93This means=94 is not clear to me. Does it =
802.11e is supported with 802.11OCB mode. Please clarify



3.  Communication Scenarios where IEEE 802.11 OCB Links are Used


   The IEEE 802.11 OCB Networks are used for vehicular communications,
   as 'Wireless Access in Vehicular Environments'.  The IP communication
   scenarios for these environments have been described in several
   documents, among which we refer the reader to one recently updated
   [I-D.petrescu-its-scenarios-reqs], about s=
cenarios and requirements
   for IP in Intelligent Transportation Systems.



[Sri] You can do bit more justice to this section.

Explain the link model.  =93STA ----802.11-OCB=97=97STA=94. Then talk about=
 the applicability in Vehicular networks, with STA's as RSU and OCB.

You may also want to talk about, how links get formed/terminated; how nodes=
 peer/discover and how mobility works ..etc.  While 802.11-OCB is clearly s=
pecified and the use of IPv6 over such link is also not radically new, but =
the operating environment which is vehicular brings many new things. That d=
escription is not present any where.


4.  Aspects introduced by the OCB mode to 802.11


   In the IEEE 802.11 OCB mode, all nodes in the wireless range can
   directly communicate with each other without authentication/
   association procedures.  Briefly, the IEEE 802.11 OCB mode has the
   following properties:



[Sri] Can you add some text on how nodes (ST1 and STA2) discover each other=
 on such links supporting 802.11 OCB mode.

   o  The use by each node of a 'wildcard' BSSID (i.e., each bit of the
      BSSID is set to 1)

   o  No IEEE 802.11 Beacon frames transmitted

   o  No authentication required

   o  No association needed

   o  No encryption provided


[Sri] Can you clarify what you mean when you say =93No xxx required=94 / =
=93No xxx needed=94  for the above capabilities.  What does =93needed=94 or=
 =93required=94 mean?  Does it mean, =93Authentication", =93Association" an=
d =93Encryption=94 is optional on this link, or that its not supported on 8=
02.11 OCB links.


   o  Flag dot11OCBActivated set to true

   The following message exchange diagram illustrates a comparison
   between traditional 802.11 and 802.11 in OCB mode.  The 'Data'



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   messages can be IP messages such as the messages used in Stateless or
   Stateful Address Auto-Configuration, or other IP messages.



[Sri] Lets separate the discussion on IP Address configuration using SLAAC/=
DHCP on such links from the above description. The Data packets here can be=
 application packets such as HTTP or other packets. May be additional discu=
ssion is needed on the IP address configuration on 802.11-OCB links.



Other
   802.11 management and control frames (non IP) may be transmitted, as
   specified in the 802.11 standard.  For information, the names of
   these messages as currently specified by the 802.11 standard are
   listed in Appendix D.







     STA                    AP              STA1                   STA2
     |                      |               |                      |
     |<------ Beacon -------|               |<------ Data -------->|
     |                      |               |                      |
     |---- Probe Req. ----->|               |<------ Data -------->|
     |<--- Probe Res. ------|               |                      |
     |                      |               |<------ Data -------->|
     |---- Auth Req. ------>|               |                      |
     |<--- Auth Res. -------|               |<------ Data -------->|
     |                      |               |                      |
     |---- Asso Req. ------>|               |<------ Data -------->|
     |<--- Asso Res. -------|               |                      |
     |                      |               |<------ Data -------->|
     |<------ Data -------->|               |                      |
     |<------ Data -------->|               |<------ Data -------->|

    (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode


   The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010
   [ieee802.11p-2010] as an amendment to IEEE Std 802.11 (TM=
) -2007,
   titled "Amendment 6: Wireless Access in Vehicular Environments".
   Since then, this amendment has been included in IEEE 802.11(TM)-2012
   [ieee802.11-2012], titled "IEEE Standard for Information t=
echnology--
   Telecommunications and information exchange between systems Local and
   metropolitan area networks--Specific requirements Part 11: Wireless
   LAN Medium Access Control (MAC) and Physical Layer (PHY)
   Specifications"; the modifications are diffused throughout various
   sections (e.g. the Time Advertisement message described in the
   earlier 802.11 (TM) p amendment is now described in section 'Frame
   formats', and the operation outside the context of a BSS described in
   section 'MLME').

   In document 802.11-2012, specifically anything referring
   "OCBActivated", or "outside the context of a basic service set" is
   actually referring to the 802.11p aspects introduced to 802.11.  Note
   that in earlier 802.11p documents the term "OCBEnabled" was used
   instead of te current "OCBActivated".





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   In order to delineate the aspects introduced by 802.11 OCB to 802.11,
   we refer to the earlier [ieee802.11p-2010].  The amendmen=
t is
   concerned with vehicular communications, where the wireless link is
   similar to that of Wireless LAN (using a PHY layer specified by
   802.11a/b/g/n), but which needs to cope with the high mobility factor
   inherent in scenarios of communications between moving vehicles, and
   between vehicles and fixed infrastructure deployed along roads.
   While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is
   concerned more with MAC modifications, and a little with PHY
   modifications; the others are mainly about PHY modifications.  It is
   possible in practice to combine a 'p' MAC with an 'a' PHY by
   operating outside the context of a BSS with OFDM at 5.4GHz.

   The 802.11 OCB links are specified to be compatible as much as
   possible with the behaviour of 802.11a/b/g/n and future generation
   IEEE WLAN links.  From the IP perspective, an 802.11 OCB MAC layer
   offers practically the same interface to IP as the WiFi and Ethernet
   layers do (802.11a/b/g/n and 802.3).



[Sri] A packet sent from a vehicle=92s OBU is received by a single RSU, or =
multiple RSU=92s? How does the link-layer resolution happen?


   To support this similarity statement (IPv6 is layered on top of LLC
   on top of 802.11 OCB similarly as on top of LLC on top of
   802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to
   analyze the differences between 802.11 OCB and 802.11 specifications.
   Whereas the 802.11p amendment specifies relatively complex and
   numerous changes to the MAC layer (and very little to the PHY layer),
   we note there are only a few characteristics which may be important
   for an implementation transmitting IPv6 packets on 802.11 OCB links.

   In the list below, the only 802.11 OCB fundamental points which
   influence IPv6 are the OCB operation and the 12Mbit/s maximum which
   may be afforded by the IPv6 applications.



[Sri] I am really not sure how link throughput (12Mbps) relates to "IPv6 su=
pport on OCB links".



   o  Operation Outside the Context of a BSS (OCB): the (earlier
      802.11p) 802.11-OCB links are operated without a Basic Service Set
      (BSS).  This means that the frames IEEE 802.11 Beacon, Association
      Request/Response, Authentication Request/Response, and similar,
      are not used.  The used identifier of BSS (BSSID) has a
      hexadecimal value always 0xffffffffffff (48 '1' bits, represented
      as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'
      BSSID), as opposed to an arbitrary BSSID value set by
      administrator (e.g.  'My-Home-AccessPoint').  The OCB operation -
      namely the lack of beacon-based scanning and lack of
      authentication - has a potentially strong impact on the use of the
      Mobile IPv6 protocol [RFC6275] a=
nd on the protocols for IP layer
      security [RFC4301].



[Sri] The document till now has been arguing heavily on how IPv6 operates s=
o naturally on these links and now I see discussion on =93Impact to a high-=
level protocol such as MIPv6=94. You may want to fix the earlier text. In a=
ny case,  the absence of link-layer security practically impacts every appl=
ication, not just MIPv6.  Also, MIPv6 does not make any assumptions on the =
link-layer security.  Also, the the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes=
 the messages readable by all other RSU=92s in proximity. I think the discu=
ssion on the nature of the link, who all see=92s the messages.. how L2 addr=
esses are resolved is not explained clearly.




   o  Timing Advertisement: is a new message defined in 802.11-OCB,
      which does not exist in 802.11a/b/g/n.  This message is used by



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      stations to inform other stations about the value of time.  It is
      similar to the time as delivered by a GNSS system (Galileo, GPS,
      ...) or by a cellular system.  This message is optional for
      implementation.  At the date of writing, an experienced reviewer
      considers that currently no field testing has used this message.
      Another implementor considers this feature implemented in an
      initial manner.  In the future, it is speculated that this message
      may be useful for very simple devices which may not have their own
      hardware source of time (Galileo, GPS, cellular network), or by
      vehicular devices situated in areas not covered by such network
      (in tunnels, underground, outdoors but shaded by foliage or
      buildings, in remote areas, etc.)



[Sri] The first part explaining Timing Advertisement messages is great, but=
 the rest of the commentary is unnecessary and not needed. We don=92t specu=
late the protocol adoption success in IETF specifications, or about the exp=
erience level of the =93reviewer" :)



   o  Frequency range: this is a characteristic of the PHY layer, with
      almost no impact to the interface between MAC and IP.  However, it
      is worth considering that the frequency range is regulated by a
      regional authority (ARCEP, ETSI, FCC, etc.); as part of the
      regulation process, specific applications are associated with
      specific frequency ranges.  In the case of 802.11-OCB, the
      regulator associates a set of frequency ranges, or slots within a
      band, to the use of applications of vehicular communications, in a
      band known as "5.9GHz".  This band is "5.9GHz" which is different
      from the bands "2.4GHz" or "5GHz" used by Wireless LAN.  However,
      as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz"
      bands is exempt from owning a license in EU (in US the 5.9GHz is a
      licensed band of spectrum; for the the fixed infrastructure an
      explicit FCC autorization is required; for an onboard device a
      'licensed-by-rule' concept applies: rule certification conformity
      is required); however technical conditions are different than
      those of the bands "2.4GHz" or "5GHz".  On one hand, the allowed
      power levels, and implicitly the maximum allowed distance between
      vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20
      dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum
      distance of approximately 1km, compared to approximately 50m.  On
      the other hand, specific conditions related to congestion
      avoidance, jamming avoidance, and radar detection are imposed on
      the use of DSRC (in US) and on the use of frequencies for
      Intelligent Transportation Systems (in EU), compared to Wireless
      LAN (802.11a/b/g/n).

   o  Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB,
      as opposed to IPv6 not being prohibited on any channel on which
      802.11a/b/g/n runs:

      *  Some channels are reserved for safety communications; the IPv6
         packets should not be sent on these channels.





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      *  At the time of writing, the prohibition is explicit at higher
         layer protocols providing services to the application; these
         higher layer protocols are specified in IEEE 1609 documents.

      *  National or regional specifications and regulations specify the
         use of different channels; these regulations must be followed.

   o  'Half-rate' encoding: as the frequency range, this parameter is
      related to PHY, and thus has not much impact on the interface
      between the IP layer and the MAC layer.

   o  In vehicular communications using 802.11-OCB links, there are
      strong privacy requirements with respect to addressing.  While the
      802.11-OCB standard does not specify anything in particular with
      respect to MAC addresses, in these settings there exists a strong
      need for dynamic change of these addresses (as opposed to the non-
      vehicular settings - real wall protection - where fixed MAC
      addresses do not currently pose some privacy risks).  This is
      further described in section Section 7.  A relevant function is
      described in IEEE 1609.3-2016 [ieee1609.3], clause 5.5.1 and=
 IEEE
      1609.4-2016 [ieee1609.4], clause 6.7.



   Other aspects particular to 802.11-OCB which are also particular to
   802.11 (e.g. the 'hidden node' operation) may have an influence on
   the use of transmission of IPv6 packets on 802.11-OCB networks.  The
   subnet structure which may be assumed in 802.11-OCB networks is
   strongly influenced by the mobility of vehicles.



[Sri] Per my earlier comment, the link model, addressing ..etc needs to be =
explained in more detail. It is not clear what exactly the =93subnet struct=
ure=94 that is assumed in 802.11-OCB.


5.  Layering of IPv6 over 802.11-OCB as over Ethernet



5.1.  Maximum Transmission Unit (MTU)


   The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is
   the same value as IPv6 packets on Ethernet links, as specified in
   [RFC2464].  This value of the MTU r=
espects the recommendation that
   every link in the Internet must have a minimum MTU of 1280 octets
   (stated in [RFC2460], and the recom=
mendations therein, especially
   with respect to fragmentation).  If IPv6 packets of size larger than
   1500 bytes are sent on an 802.11-OCB interface card then the IP stack
   will fragment.  In case there are IP fragments, the field "Sequence
   number" of the 802.11 Data header containing the IP fragment field is
   increased.

   Non-IP packets such as WAVE Short Message Protocol (WSMP) can be
   delivered on 802.11-OCB links.  Specifications of these packets are
   out of scope of this document, and do not impose any limit on the MTU
   size, allowing an arbitrary number of 'containers'.  Non-IP packets
   such as ETSI 'geonet' packets have an MTU of 1492 bytes.



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   The Equivalent Transmit Time on Channel is a concept that may be used
   as an alternative to the MTU concept.  A rate of transmission may be
   specified as well.  The ETTC, rate and MTU may be in direct
   relationship.


[Sri] The last paragraph needs some additional context. Did 802.11-OCB intr=
oduce ETTC concept?




5.2.  Frame Format


   IP packets are transmitted over 802.11-OCB as standard Ethernet
   packets.  As with all 802.11 frames, an Ethernet adaptation layer is
   used with 802.11-OCB as well.  This Ethernet Adaptation Layer
   performing 802.11-to-Ethernet is described in Section 5.2.1.  Th=
e
   Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD,
   or otherwise #86DD).

   The Frame format for transmitting IPv6 on 802.11-OCB networks is the
   same as transmitting IPv6 on Ethernet networks, and is described in
   section 3 of [RFC2464].  =
The frame format for transmitting IPv6
   packets over Ethernet is illustrated below:


                    0                   1
                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |          Destination          |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |             Source            |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |             IPv6              |
                    +-                             -+
                    |            header             |
                    +-                             -+
                    |             and               |
                    +-                             -+
                    /            payload ...        /
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    (Each tic mark represents one bit.)





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   Ethernet II Fields:

   Destination Ethernet Address
      the MAC destination address.

   Source Ethernet Address
      the MAC source address.

   1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
      binary representation of the EtherType value 0x86DD.

   IPv6 header and payload
      the IPv6 packet containing IPv6 header and payload.


5.2.1.  Ethernet Adaptation Layer


   In general, an 'adaptation' layer is inserted between a MAC layer and
   the Networking layer.  This is used to transform some parameters
   between their form expected by the IP stack and the form provided by
   the MAC layer.  For example, an 802.15.4 adaptation layer may perform
   fragmentation and reassembly operations on a MAC whose maximum Packet
   Data Unit size is smaller than the minimum MTU recognized by the IPv6
   Networking layer.  Other examples involve link-layer address
   transformation, packet header insertion/removal, and so on.

   An Ethernet Adaptation Layer makes an 802.11 MAC look to IP
   Networking layer as a more traditional Ethernet layer.  At reception,
   this layer takes as input the IEEE 802.11 Data Header and the
   Logical-Link Layer Control Header and produces an Ethernet II Header.
   At sending, the reverse operation is performed.


 +--------------------+------------+-------------+---------+-----------+
 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer|
 +--------------------+------------+-------------+---------+-----------+
  \                               /                         \         /
    -----------------------------                             --------
                   ^---------------------------------------------/
                   |
           802.11-to-Ethernet Adaptation Layer
                   |
                   v
 +---------------------+-------------+---------+
 | Ethernet II Header  | IPv6 Header | Payload |
 +---------------------+-------------+---------+






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   The Receiver and Transmitter Address fields in the 802.11 Data Header
   contain the same values as the Destination and the Source Address
   fields in the Ethernet II Header, respectively.  The value of the
   Type field in the LLC Header is the same as the value of the Type
   field in the Ethernet II Header.

   The ".11 Trailer" contains solely a 4-byte Frame Check Sequence.

   The Ethernet Adaptation Layer performs operations in relation to IP
   fragmentation and MTU.  One of these operations is briefly described
   in section Section 5.1.

   In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11
   Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in
   the following figure:


+--------------------+-------------+-------------+---------+-----------+
| 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------+-----------+

or

+--------------------+-------------+-------------+---------+-----------+
| 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------+-----------+


   The distinction between the two formats is given by the value of the
   field "Type/Subtype".  The value of the field "Type/Subtype" in the
   802.11 Data header is 0x0020.  The value of the field "Type/Subtype"
   in the 802.11 QoS header is 0x0028.

   The mapping between qos-related fields in the IPv6 header (e.g.
   "Traffic Class", "Flow label") and fields in the "802.11 QoS Data
   Header" (e.g.  "QoS Control") are not specified in this document.
   Guidance for a potential mapping is provided in
   [I-D.ietf-tsvwg-ieee-802-11], although it is no=
t specific to OCB
   mode.




[Sri] The applicability of the QoS mapping draft to 802.11-OCB needs furthe=
r investigation, IMO.




5.3.  Link-Local Addresses


   The link-local address of an 802.11-OCB interface is formed in the
   same manner as on an Ethernet interface.  This manner is described in
   section 5 of [RFC2464].




[Sri] Does this go against the 8064 recommendation on Interface identifier =
generation?

May be RFC7217 for interface identifier generation in conjunction with the =
link-local address generation per RFC2464

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5.4.  Address Mapping


   For unicast as for multicast, there is no change from the unicast and
   multicast address mapping format of Ethernet interfaces, as defined
   by sections 6 and 7 of [RFC2464].




[Sri] RFC6085 specified mapping is also relevant; If the communication peer=
s are aware that there is only one peer, it should apply 6085 specified map=
ping. That mode is relevant for 802.11-OCB types links as well.



5.4.1.  Address Mapping -- Unicast


   The procedure for mapping IPv6 unicast addresses into Ethernet link-
   layer addresses is described in [RFC4861].  The Source/Target Link-
   layer Address option has the following form when the link-layer is
   Ethernet.


[Sri] I thought, mapping of IPv6 unicast addresses to Ethernet link-layer a=
ddresses is specified in section 6, of RFC2464 and not in RFC4861.




                      0                   1
                      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |     Type      |    Length     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |                               |
                     +-          Ethernet           -+
                     |                               |
                     +-           Address           -+
                     |                               |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Option fields:

   Type
      1 for Source Link-layer address.
      2 for Target Link-layer address.

   Length
      1 (in units of 8 octets).

   Ethernet Address
      The 48 bit Ethernet IEEE 802 address, in canonical bit order.


5.4.2.  Address Mapping -- Multicast


   IPv6 protocols often make use of IPv6 multicast addresses in the
   destination field of IPv6 headers.  For example, an ICMPv6 link-
   scoped Neighbor Advertisement is sent to the IPv6 address ff02::1
   denoted "all-nodes" address.  When transmitting these packets on
   802.11-OCB links it is necessary to map the IPv6 address to a MAC
   address.




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   The same mapping requirement applies to the link-scoped multicast
   addresses of other IPv6 protocols as well.  In DHCPv6, the
   "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF the
   "All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped
   on a multicast MAC address.

   An IPv6 packet with a multicast destination address DST, consisting
   of the sixteen octets DST[1] through DST[16], is transmitted to the
   IEEE 802.11-OCB MAC multicast address whose first two octets are the
   value 0x3333 and whose last four octets are the last four octets of
   DST.


[Sri] Please add a reference to Section 7, RFC4861 and also RFC6085. In gen=
eral, for both unicast and multicast, you may want to clearly say that this=
 is per the existing specs and duplicated here for convenience.


                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |   DST[13]     |   DST[14]     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |   DST[15]     |   DST[16]     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   A Group ID TBD of length 112bits may be requested from IANA; this
   Group ID signifies "All 80211OCB Interfaces Address".  Only the least
   32 significant bits of this "All 80211OCB Interfaces Address" will be
   mapped to and from a MAC multicast address.

   Transmitting IPv6 packets to multicast destinations over 802.11 links
   proved to have some performance issues
   [I-D.perkins-intarea-multicast-ieee802].  These issues may be
   exacerbated in OCB mode.  Solutions for these problems should
   consider the OCB mode of operation.


5.5.  Stateless Autoconfiguration


   The Interface Identifier for an 802.11-OCB interface is formed using
   the same rules as the Interface Identifier for an Ethernet interface;
   this is described in section 4 of [RFC2464].  No changes are needed,
   but some care must be taken when considering the use of the SLAAC
   procedure.



[Sri] Per my earlier comment, please refer to the current recommendation on=
 interface-identifier generation and its use in link-local, global or other=
 addresses.

The bits in the the interface identifier have no generic meaning and the id=
entifier should be treated as an opaque value. The bits 'Universal' and 'Gr=
oup' in the identifier of an 802.11-OCB interface are significant, as this =
is an IEEE link-layer address. The details of this significance are describ=
ed in [I-D.ietf-6man-ug]. Petrescu, et al. Expires February =
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   As with all Ethernet and 802.11 interface identifiers ([RFC7721]),
   the identifier of an 802.11-OCB interface may involve privacy risks.
   A vehicle embarking an On-Board Unit whose egress interface is
   802.11-OCB may expose itself to eavesdropping and subsequent
   correlation of data; this may reveal data considered private by the
   vehicle owner; there is a risk of being tracked; see the privacy
   considerations described in Appendix C.



[Sri] I think there are other security issues here; the absence of link-lay=
er security opens up Mac-spoofing and IP address hijacking.  That should be=
 mentioned.



   If stable Interface Identifiers are needed in order to form IPv6
   addresses on 802.11-OCB links, it is recommended to follow the
   recommendation in [I-D.ietf-6man-default-iids].


5.6.  Subnet Structure


   The 802.11 networks in OCB mode may be considered as 'ad-hoc'
   networks.  The addressing model for such networks is described in
   [RFC5889].



[Sri] Per my earlier comment, there is no system level view of the network =
where 802.11-OCB links are used. So, in the absence of such discussion So, =
I am not sure what part of RFC5889 is applicable here. For example, link-lo=
cal addresses may just work fine.



6.  Example IPv6 Packet captured over a IEEE 802.11-OCB link


   We remind that a main goal of this document is to make the case that
   IPv6 works fine over 802.11-OCB networks.  Consequently, this section
   is an illustration of this concept and thus can help the implementer
   when it comes to running IPv6 over IEEE 802.11-OCB.  By way of
   example we show that there is no modification in the headers when
   transmitted over 802.11-OCB networks - they are transmitted like any
   other 802.11 and Ethernet packets.

   We describe an experiment of capturing an IPv6 packet on an
   802.11-OCB link.  In this experiment, the packet is an IPv6 Router
   Advertisement.  This packet is emitted by a Router on its 802.11-OCB
   interface.  The packet is captured on the Host, using a network
   protocol analyzer (e.g.  Wireshark); the capture is performed in two
   different modes: direct mode and 'monitor' mode.  The topology used
   during the capture is depicted below.


              +--------+                                +-------+
              |        |        802.11-OCB Link         |       |
           ---| Router |--------------------------------| Host  |
              |        |                                |       |
              +--------+                                +-------+


   During several capture operations running from a few moments to
   several hours, no message relevant to the BSSID contexts were
   captured (no Association Request/Response, Authentication Req/Resp,




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   Beacon).  This shows that the operation of 802.11-OCB is outside the
   context of a BSSID.

   Overall, the captured message is identical with a capture of an IPv6
   packet emitted on a 802.11b interface.  The contents are precisely
   similar.



[Sri] I suggest moving this discussion under the section =93Implementation =
Status=94, which will eventually be removed from the RFC. There is nothing =
new here. This are details on experimentation. But, if you think there is s=
ome useful information  such as discussion on Capture mode ..etc, you may w=
ant to move this entire section to Appendix. Implementors may use these too=
ls for verification.




6.1.  Capture in Monitor Mode


   The IPv6 RA packet captured in monitor mode is illustrated below.
   The radio tap header provides more flexibility for reporting the
   characteristics of frames.  The Radiotap Header is prepended by this
   particular stack and operating system on the Host machine to the RA
   packet received from the network (the Radiotap Header is not present
   on the air).  The implementation-dependent Radiotap Header is useful
   for piggybacking PHY information from the chip's registers as data in
   a packet understandable by userland applications using Socket
   interfaces (the PHY interface can be, for example: power levels, data
   rate, ratio of signal to noise).

   The packet present on the air is formed by IEEE 802.11 Data Header,
   Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.



     Radiotap Header v0
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Header Revision|  Header Pad   |    Header length              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Present flags                         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Data Rate     |             Pad                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IEEE 802.11 Data Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Type/Subtype and Frame Ctrl  |          Duration             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Receiver Address...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Receiver Address           |      Transmitter Address...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Transmitter Address                                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                            BSS Id...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... BSS Id                     |  Frag Number and Seq Number   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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     Logical-Link Control Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |      DSAP   |I|     SSAP    |C| Control field | Org. code...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Organizational Code        |             Type              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                         Source Address                        +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                      Destination Address                      +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+-


   The value of the Data Rate field in the Radiotap header is set to 6
   Mb/s.  This indicates the rate at which this RA was received.





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   The value of the Transmitter address in the IEEE 802.11 Data Header
   is set to a 48bit value.  The value of the destination address is
   33:33:00:00:00:1 (all-nodes multicast address).  The value of the BSS
   Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network
   protocol analyzer as being "broadcast".  The Fragment number and
   sequence number fields are together set to 0x90C6.

   The value of the Organization Code field in the Logical-Link Control
   Header is set to 0x0, recognized as "Encapsulated Ethernet".  The
   value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise
   #86DD), recognized as "IPv6".

   A Router Advertisement is periodically sent by the router to
   multicast group address ff02::1.  It is an icmp packet type 134.  The
   IPv6 Neighbor Discovery's Router Advertisement message contains an
   8-bit field reserved for single-bit flags, as described in [RFC4861].

   The IPv6 header contains the link local address of the router
   (source) configured via EUI-64 algorithm, and destination address set
   to ff02::1.  Recent versions of network protocol analyzers (e.g.
   Wireshark) provide additional informations for an IP address, if a
   geolocalization database is present.  In this example, the
   geolocalization database is absent, and the "GeoIP" information is
   set to unknown for both source and destination addresses (although
   the IPv6 source and destination addresses are set to useful values).
   This "GeoIP" can be a useful information to look up the city,
   country, AS number, and other information for an IP address.


[Sri] Not sure, why all of this text should be in the specification.


   The Ethernet Type field in the logical-link control header is set to
   0x86dd which indicates that the frame transports an IPv6 packet.  In
   the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
   which is he corresponding multicast MAC address.  The BSS id is a
   broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link
   duration between vehicles and the roadside infrastructure, there is
   no need in IEEE 802.11-OCB to wait for the completion of association
   and authentication procedures before exchanging data.  IEEE
   802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)
   and may start communicating as soon as they arrive on the
   communication channel.


6.2.  Capture in Normal Mode


   The same IPv6 Router Advertisement packet described above (monitor
   mode) is captured on the Host, in the Normal mode, and depicted
   below.






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     Ethernet II Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Destination...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ...Destination                 |           Source...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ...Source                                                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |          Type                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                         Source Address                        +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                      Destination Address                      +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+-





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   One notices that the Radiotap Header is not prepended, and that the
   IEEE 802.11 Data Header and the Logical-Link Control Headers are not
   present.  On another hand, a new header named Ethernet II Header is
   present.

   The Destination and Source addresses in the Ethernet II header
   contain the same values as the fields Receiver Address and
   Transmitter Address present in the IEEE 802.11 Data Header in the
   "monitor" mode capture.

   The value of the Type field in the Ethernet II header is 0x86DD
   (recognized as "IPv6"); this value is the same value as the value of
   the field Type in the Logical-Link Control Header in the "monitor"
   mode capture.

   The knowledgeable experimenter will no doubt notice the similarity of
   this Ethernet II Header with a capture in normal mode on a pure
   Ethernet cable interface.

   It may be interpreted that an Adaptation layer is inserted in a pure
   IEEE 802.11 MAC packets in the air, before delivering to the
   applications.  In detail, this adaptation layer may consist in
   elimination of the Radiotap, 802.11 and LLC headers and insertion of
   the Ethernet II header.  In this way, it can be stated that IPv6 runs
   naturally straight over LLC over the 802.11-OCB MAC layer, as shown
   by the use of the Type 0x86DD, and assuming an adaptation layer
   (adapting 802.11 LLC/MAC to Ethernet II header).


7.  Security Considerations


   Any security mechanism at the IP layer or above that may be carried
   out for the general case of IPv6 may also be carried out for IPv6
   operating over 802.11-OCB.



   802.11-OCB does not provide any cryptographic protection, because it
   operates outside the context of a BSS (no Association Request/
   Response, no Challenge messages).  Any attacker can therefore just
   sit in the near range of vehicles, sniff the network (just set the
   interface card's frequency to the proper range) and perform attacks
   without needing to physically break any wall.  Such a link is way
   less protected than commonly used links (wired link or protected
   802.11).


[Sri] Per my earlier comment, there is more than one attack vector possible

1.) Absence of link-layer security and the potential for mac address spoofi=
ng

2.) IP address / Session hijacking

3.) Data privacy per your text



   At the IP layer, IPsec can be used to protect unicast communications,
   and SeND can be used for multicast communications.


[Sri] IPSec can be used for protecting both multicast or unicast communicat=
ion; RFC-5374 with GDOI.




 If no protection
   is used by the IP layer, upper layers should be protected.
   Otherwise, the end-user or system should be warned about the risks
   they run.



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   As with all Ethernet and 802.11 interface identifiers, there may
   exist privacy risks in the use of 802.11-OCB interface identifiers.
   Moreover, in outdoors vehicular settings, the privacy risks are more
   important than in indoors settings.  New risks are induced by the
   possibility of attacker sniffers deployed along routes which listen
   for IP packets of vehicles passing by.  For this reason, in the
   802.11-OCB deployments, there is a strong necessity to use protection
   tools such as dynamically changing MAC addresses.  This may help
   mitigate privacy risks to a certain level.  On another hand, it may
   have an impact in the way typical IPv6 address auto-configuration is
   performed for vehicles (SLAAC would rely on MAC addresses amd would
   hence dynamically change the affected IP address), in the way the
   IPv6 Privacy addresses were used, and other effects.


8.  IANA Considerations



9.  Contributors


   Romain Kuntz contributed extensively about IPv6 handovers between
   links running outside the context of a BSS (802.11-OCB links).

   Tim Leinmueller contributed the idea of the use of IPv6 over
   802.11-OCB for distribution of certificates.

   Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey
   Voronov provided significant feedback on the experience of using IP
   messages over 802.11-OCB in initial trials.

   Michelle Wetterwald contributed extensively the MTU discussion,
   offered the ETSI ITS perspective, and reviewed other parts of the
   document.


10.  Acknowledgements


   The authors would like to thank Witold Klaudel, Ryuji Wakikawa,
   Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan
   Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray
   Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,
   Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,
   Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,
   Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and
   William Whyte.  Their valuable comments clarified certain issues and
   generally helped to improve the document.

   Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB
   drivers for linux and described how.





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   For the multicast discussion, the authors would like to thank Owen
   DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and
   participants to discussions in network working groups.

   The authours would like to thank participants to the Birds-of-
   a-Feather "Intelligent Transportation Systems" meetings held at IETF
   in 2016.


11.  References



11.1.  Normative References


   [I-D.ietf-6man-default-iids]
              Gont, F., Cooper, A., Thaler, D., and S. LIU,
              "Recommendation on Stable IPv6 Interface Identifiers",
              draft-ietf-6man-default-iids-16 (work in progress),
              September 2016.

   [I-D.ietf-6man-ug]
              Carpenter, B. and S. Jiang, "Significance of IPv6
              Interface Identifiers", draft-ietf-6man-ug-06 (work in
              progress), December 2013.

   [I-D.ietf-tsvwg-ieee-802-11]
              Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE
              802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-06 (work in
              progress), August 2017.

   [RFC1042]  Postel, J. and J. Reynolds, "Standard for the transmission
              of IP datagrams over IEEE 802 networks", STD 43, RFC 1042,
              DOI 10.17487/RFC1042, February 1988, 
              editor.org/info/rfc1042>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997, 
              editor.org/info/rfc2119>.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
              December 1998, .

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, DOI=
 10.17487/RFC2464, December 1998,
              .






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   [RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol",
              RFC 3963, DOI 10.17487/R=
FC3963, January 2005,
              .

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security", BCP 106, RFC 4086,
              DOI 10.17487/RFC4086, June 2005, 
              editor.org/info/rfc4086>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, .

   [RFC4429]  Moore, N., "Optimistic Duplicate Address Detection (DAD)
              for IPv6", RFC 4429, DOI=
 10.17487/RFC4429, April 2006,
              .

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007, 
              editor.org/info/rfc4861>.

   [RFC5889]  Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing
              Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889,
              September 2010, .

   [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
              2011, .

   [RFC6775]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
              Bormann, "Neighbor Discovery Optimization for IPv6 over
              Low-Power Wireless Personal Area Networks (6LoWPANs)",
              RFC 6775, DOI 10.17487/R=
FC6775, November 2012,
              .

   [RFC7721]  Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
              Considerations for IPv6 Address Generation Mechanisms",
              RFC 7721, DOI 10.17487/R=
FC7721, March 2016,
              .


11.2.  Informative References









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   [fcc-cc]   "'Report and Order, Before the Federal Communications
              Commission Washington, D.C. 20554', FCC 03-324, Released
              on February 10, 2004, document FCC-03-324A1.pdf, document
              freely available at URL
              http://www.its.dot.gov/exit/fcc_edocs.htm downloaded on
              October 17th, 2013.".

   [fcc-cc-172-184]
              "'Memorandum Opinion and Order, Before the Federal
              Communications Commission Washington, D.C. 20554', FCC
              06-10, Released on July 26, 2006, document FCC-
              06-110A1.pdf, document freely available at URL
              http://hraunfoss.fcc.gov/edocs_public/attachmatch/
              FCC-06-110A1.pdf downloaded on June 5th, 2014.".

   [I-D.jeong-ipwave-vehicular-networking-survey]
              Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M.
              Wetterwald, "Survey on IP-based Vehicular Networking for
              Intelligent Transportation Systems", draft-jeong-ipwave-
              vehicular-networking-survey-03 (work in progress), June
              2017.

   [I-D.perkins-intarea-multicast-ieee802]
              Perkins, C., Stanley, D., Kumari, W., and J. Zuniga,
              "Multicast Considerations over IEEE 802 Wireless Media",
              draft-perkins-intarea-multicast-ieee802-03 (work in
              progress), July 2017.

   [I-D.petrescu-its-scenarios-reqs]
              Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel,
              "Scenarios and Requirements for IP in Intelligent
              Transportation Systems", draft-petrescu-its-scenarios-
              reqs-03 (work in progress), October 2013.

   [ieee1609.2]
              "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Security Services for
              Applications and Management Messages.  Example URL
              http://ieeexplore.ieee.org/document/7426684/ accessed on
              August 17th, 2017.".

   [ieee1609.3]
              "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Networking Services.
              Example URL http://ieeexplore.ieee.org/document/7458115/
              accessed on August 17th, 2017.".





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   [ieee1609.4]
              "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Multi-Channel
              Operation.  Example URL
              http://ieeexplore.ieee.org/document/7435228/ accessed on
              August 17th, 2017.".

   [ieee802.11-2012]
              "802.11-2012 - IEEE Standard for Information technology--
              Telecommunications and information exchange between
              systems Local and metropolitan area networks--Specific
              requirements Part 11: Wireless LAN Medium Access Control
              (MAC) and Physical Layer (PHY) Specifications.  Downloaded
              on October 17th, 2013, from IEEE Standards, document
              freely available at URL
              http://standards.ieee.org/findstds/
              standard/802.11-2012.html retrieved on October 17th,
              2013.".

   [ieee802.11p-2010]
              "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information
              Technology - Telecommunications and information exchange
              between systems - Local and metropolitan area networks -
              Specific requirements, Part 11: Wireless LAN Medium Access
              Control (MAC) and Physical Layer (PHY) Specifications,
              Amendment 6: Wireless Access in Vehicular Environments;
              document freely available at URL
              http://standards.ieee.org/getieee802/
              download/802.11p-2010.pdf retrieved on September 20th,
              2013.".


Appendix A.  ChangeLog


   The changes are listed in reverse chronological order, most recent
   changes appearing at the top of the list.

   From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave-
   ipv6-over-80211ocb-04

   o  Removed a few informative references pointing to Dx draft IEEE
      1609 documents.

   o  Removed outdated informative references to ETSI documents.

   o  Added citations to IEEE 1609.2, .3 and .4-2016.

   o  Minor textual issues.




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   From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave-
   ipv6-over-80211ocb-03

   o  Keep the previous text on multiple addresses, so remove talk about
      MIP6, NEMOv6 and MCoA.

   o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.

   o  Clarified the figure showing Infrastructure mode and OCB mode side
      by side.

   o  Added a reference to the IP Security Architecture RFC.

   o  Detailed the IPv6-per-channel prohibition paragraph which reflects
      the discussion at the last IETF IPWAVE WG meeting.

   o  Added section "Address Mapping -- Unicast".

   o  Added the ".11 Trailer" to pictures of 802.11 frames.

   o  Added text about SNAP carrying the Ethertype.

   o  New RSU definition allowing for it be both a Router and not
      necessarily a Router some times.

   o  Minor textual issues.

   From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave-
   ipv6-over-80211ocb-02

   o  Replaced almost all occurences of 802.11p with 802.11-OCB, leaving
      only when explanation of evolution was necessary.

   o  Shortened by removing parameter details from a paragraph in the
      Introduction.

   o  Moved a reference from Normative to Informative.

   o  Added text in intro clarifying there is no handover spec at IEEE,
      and that 1609.2 does provide security services.

   o  Named the contents the fields of the EthernetII header (including
      the Ethertype bitstring).

   o  Improved relationship between two paragraphs describing the
      increase of the Sequence Number in 802.11 header upon IP
      fragmentation.




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   o  Added brief clarification of "tracking".

   From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave-
   ipv6-over-80211ocb-01

   o  Introduced message exchange diagram illustrating differences
      between 802.11 and 802.11 in OCB mode.

   o  Introduced an appendix listing for information the set of 802.11
      messages that may be transmitted in OCB mode.

   o  Removed appendix sections "Privacy Requirements", "Authentication
      Requirements" and "Security Certificate Generation".

   o  Removed appendix section "Non IP Communications".

   o  Introductory phrase in the Security Considerations section.

   o  Improved the definition of "OCB".

   o  Introduced theoretical stacked layers about IPv6 and IEEE layers
      including EPD.

   o  Removed the appendix describing the details of prohibiting IPv6 on
      certain channels relevant to 802.11-OCB.

   o  Added a brief reference in the privacy text about a precise clause
      in IEEE 1609.3 and .4.

   o  Clarified the definition of a Road Side Unit.

   o  Removed the discussion about security of WSA (because is non-IP).

   o  Removed mentioning of the GeoNetworking discussion.

   o  Moved references to scientific articles to a separate 'overview'
      draft, and referred to it.


Appendix B.  Changes Needed on a software driver 802.11a to become a

             802.11-OCB driver

   The 802.11p amendment modifies both the 802.11 stack's physical and
   MAC layers but all the induced modifications can be quite easily
   obtained by modifying an existing 802.11a ad-hoc stack.

   Conditions for a 802.11a hardware to be 802.11-OCB compliant:





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   o  The chip must support the frequency bands on which the regulator
      recommends the use of ITS communications, for example using IEEE
      802.11-OCB layer, in France: 5875MHz to 5925MHz.

   o  The chip must support the half-rate mode (the internal clock
      should be able to be divided by two).

   o  The chip transmit spectrum mask must be compliant to the "Transmit
      spectrum mask" from the IEEE 802.11p amendment (but experimental
      environments tolerate otherwise).

   o  The chip should be able to transmit up to 44.8 dBm when used by
      the US government in the United States, and up to 33 dBm in
      Europe; other regional conditions apply.

   Changes needed on the network stack in OCB mode:

   o  Physical layer:

      *  The chip must use the Orthogonal Frequency Multiple Access
         (OFDM) encoding mode.

      *  The chip must be set in half-mode rate mode (the internal clock
         frequency is divided by two).

      *  The chip must use dedicated channels and should allow the use
         of higher emission powers.  This may require modifications to
         the regulatory domains rules, if used by the kernel to enforce
         local specific restrictions.  Such modifications must respect
         the location-specific laws.

      MAC layer:

      *  All management frames (beacons, join, leave, and others)
         emission and reception must be disabled except for frames of
         subtype Action and Timing Advertisement (defined below).

      *  No encryption key or method must be used.

      *  Packet emission and reception must be performed as in ad-hoc
         mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).

      *  The functions related to joining a BSS (Association Request/
         Response) and for authentication (Authentication Request/Reply,
         Challenge) are not called.

      *  The beacon interval is always set to 0 (zero).




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      *  Timing Advertisement frames, defined in the amendment, should
         be supported.  The upper layer should be able to trigger such
         frames emission and to retrieve information contained in
         received Timing Advertisements.


Appendix C.  Design Considerations


   The networks defined by 802.11-OCB are in many ways similar to other
   networks of the 802.11 family.  In theory, the encapsulation of IPv6
   over 802.11-OCB could be very similar to the operation of IPv6 over
   other networks of the 802.11 family.  However, the high mobility,
   strong link asymetry and very short connection makes the 802.11-OCB
   link significantly different from other 802.11 networks.  Also, the
   automotive applications have specific requirements for reliability,
   security and privacy, which further add to the particularity of the
   802.11-OCB link.


C.1.  Vehicle ID


   Automotive networks require the unique representation of each of
   their node.  Accordingly, a vehicle must be identified by at least
   one unique identifier.  The current specification at ETSI and at IEEE
   1609 identifies a vehicle by its MAC address uniquely obtained from
   the 802.11-OCB NIC.

   A MAC address uniquely obtained from a IEEE 802.11-OCB NIC
   implicitely generates multiple vehicle IDs in case of multiple
   802.11-OCB NICs.  A mechanims to uniquely identify a vehicle
   irrespectively to the different NICs and/or technologies is required.


C.2.  Reliability Requirements


   The dynamically changing topology, short connectivity, mobile
   transmitter and receivers, different antenna heights, and many-to-
   many communication types, make IEEE 802.11-OCB links significantly
   different from other IEEE 802.11 links.  Any IPv6 mechanism operating
   on IEEE 802.11-OCB link MUST support strong link asymetry, spatio-
   temporal link quality, fast address resolution and transmission.

   IEEE 802.11-OCB strongly differs from other 802.11 systems to operate
   outside of the context of a Basic Service Set.  This means in
   practice that IEEE 802.11-OCB does not rely on a Base Station for all
   Basic Service Set management.  In particular, IEEE 802.11-OCB SHALL
   NOT use beacons.  Any IPv6 mechanism requiring L2 services from IEEE
   802.11 beacons MUST support an alternative service.






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   Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
   implement a mechanism for transmitter and receiver to converge to a
   common channel.

   Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST
   implement an distributed mechanism to authenticate transmitters and
   receivers without the support of a DHCP server.

   Time synchronization not being available, IPv6 over IEEE 802.11-OCB
   MUST implement a higher layer mechanism for time synchronization
   between transmitters and receivers without the support of a NTP
   server.

   The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB
   MUST disable management mechanisms requesting acknowledgements or
   replies.

   The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE
   802.11-OCB MUST implement fast IPv6 mobility management mechanisms.


C.3.  Multiple interfaces


   There are considerations for 2 or more IEEE 802.11-OCB interface
   cards per vehicle.  For each vehicle taking part in road traffic, one
   IEEE 802.11-OCB interface card could be fully allocated for Non IP
   safety-critical communication.  Any other IEEE 802.11-OCB may be used
   for other type of traffic.

   The mode of operation of these other wireless interfaces is not
   clearly defined yet.  One possibility is to consider each card as an
   independent network interface, with a specific MAC Address and a set
   of IPv6 addresses.  Another possibility is to consider the set of
   these wireless interfaces as a single network interface (not
   including the IEEE 802.11-OCB interface used by Non IP safety
   critical communications).  This will require specific logic to
   ensure, for example, that packets meant for a vehicle in front are
   actually sent by the radio in the front, or that multiple copies of
   the same packet received by multiple interfaces are treated as a
   single packet.  Treating each wireless interface as a separate
   network interface pushes such issues to the application layer.

   The privacy requirements of [] imply that if these multiple
   interfaces are represented by many network interface, a single
   renumbering event SHALL cause renumbering of all these interfaces.
   If one MAC changed and another stayed constant, external observers
   would be able to correlate old and new values, and the privacy
   benefits of randomization would be lost.




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   The privacy requirements of Non IP safety-critical communications
   imply that if a change of pseudonyme occurs, renumbering of all other
   interfaces SHALL also occur.


C.4.  MAC Address Generation


   When designing the IPv6 over 802.11-OCB address mapping, we will
   assume that the MAC Addresses will change during well defined
   "renumbering events".  The 48 bits randomized MAC addresses will have
   the following characteristics:

   o  Bit "Local/Global" set to "locally admninistered".

   o  Bit "Unicast/Multicast" set to "Unicast".

   o  46 remaining bits set to a random value, using a random number
      generator that meets the requirements of [RFC4086].

   The way to meet the randomization requirements is to retain 46 bits
   from the output of a strong hash function, such as SHA256, taking as
   input a 256 bit local secret, the "nominal" MAC Address of the
   interface, and a representation of the date and time of the
   renumbering event.


Appendix D.  IEEE 802.11 Messages Transmitted in OCB mode


   For information, at the time of writing, this is the list of IEEE
   802.11 messages that may be transmitted in OCB mode, i.e. when
   dot11OCBActivated is true in a STA:

   o  The STA may send management frames of subtype Action and, if the
      STA maintains a TSF Timer, subtype Timing Advertisement;

   o  The STA may send control frames, except those of subtype PS-Poll,
      CF-End, and CF-End plus CFAck;

   o  The STA may send data frames of subtype Data, Null, QoS Data, and
      QoS Null.

Authors' Addresses



--_000_D5C8D56522C0C0sgundaveciscocom_
Content-Type: text/html; charset="Windows-1252"
Content-ID: 
Content-Transfer-Encoding: quoted-printable












Attached is my review feedback. 







In general there is lot of good information in the document. But, ther=
e are also few areas where additional clarifications will greatly help.






1.) Its not clear, if the document makes any assumption on the operati=
ng environment/communication profile. There is not much discussion on that =
aspect; For example, Is it always a one-hop communication between RSU and O=
BU where the 802.11-OCB link?  So,
 is the use of IPv6 only in that context of 1-hop communication? 






2.) There is also no discussion on how these links get formed in vehic=
ular environment and when they are attached/detached. 







3.) How do nodes discover each other?  How does ND resolution wor=
k? Are these messages received by a multiple RSU=92s, or a single RSU? What=
s the implication of that. Note that you don=92t have that issue in 802.11,=
 given the association to an access point,
 which in turn maps the links to a VLAN/subnet.







4.) What happens as a vehicle moves between RSU=92s, how does it impac=
t address configuration?   Is DHCPv6 based address configuration relev=
ant here?












 Please see inline for additional comments.













-------------------------------=
-----------------------------------

 
Transmission of IPv6 Packets over IEEE 802.11 Networks in mo=
de Outside

        
the Context of a Basic Service Set (IPv6-over-80211oc=
b)

              
draft-ietf-ipwave-ipv6-over-80211ocb-04.txt






[S=
ri] May be change to, =93..in mode .." =97> =93..operatin=
g in mode ..=94  ?








Abstract

   In order to transmit IPv6 packets on IEEE 802.11 networks run outside
   the context of a basic service set (OCB, earlier "802.11p") th=
ere is
   a need to define a few parameters such as the recommended Maximum
   Transmission Unit size, the header format preceding the IPv6 header,
   the Type value within it, and others.  This document describes these
   parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
   layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
   Ethernet layers - by using an Ethernet Adaptation Layer.



[Sri] Is it =93recommended MTU size", or "supported MTU size on the 802=
.11 OCB link? 








   In addition, the document at=
tempts to list what is different in
   802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
   layers, layers over which IPv6 protocols operates without issues.
   Most notably, the operation outside the context of a BSS (OCB) has
   impact on IPv6 handover behaviour and on IPv6 security.



[Sri] Minor comment. May be instead of using the =93layer=94 terminology, y=
ou may want to present this as IPv6 support on "802.11 OCB" links=
. 





   An example of an IPv6 packet=
 captured while transmitted over an IEEE
   802.11 OCB link (802.11p) is given.



[Sri] Last paragraph can be ommitted in my view. That=
=92s too much of detail for Abstract.





Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 a=
nd BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute



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   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at htt=
p://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 18, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.or=
g/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . .=
 . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . .=
 . . . . . .   5
   3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    6
   4.  Aspects introduced by the OCB mode to 802.11  . .=
 . . . . . .   6
   5.  Layering of IPv6 over 802.11-OCB as over Ethernet=
 . . . . . .  10
     5.1.  Maximum Transmission Unit (MTU) . . . . . .=
 . . . . . . .  10
     5.2.  Frame Format  . . . . . . . . . . . . . . .=
 . . . . . . .  11
       5.2.1.  Ethernet Adaptation Layer . . . . . .=
 . . . . . . . .  12
     5.3.  Link-Local Addresses  . . . . . . . . . . .=
 . . . . . . .  13
     5.4.  Address Mapping . . . . . . . . . . . . . .=
 . . . . . . .  14
       5.4.1.  Address Mapping -- Unicast  . . . . .=
 . . . . . . . .  14
       5.4.2.  Address Mapping -- Multicast  . . . .=
 . . . . . . . .  14
     5.5.  Stateless Autoconfiguration . . . . . . . .=
 . . . . . . .  15
     5.6.  Subnet Structure  . . . . . . . . . . . . .=
 . . . . . . .  16
   6.  Example IPv6 Packet captured over a IEEE 802.11-O=
CB link  . .  16
     6.1.  Capture in Monitor Mode . . . . . . . . . .=
 . . . . . . .  17
     6.2.  Capture in Normal Mode  . . . . . . . . . .=
 . . . . . . .  19
   7.  Security Considerations . . . . . . . . . . . . .=
 . . . . . .  21
   8.  IANA Considerations . . . . . . . . . . . . . . .=
 . . . . . .  22
   9.  Contributors  . . . . . . . . . . . . . . . . . .=
 . . . . . .  22
   10. Acknowledgements  . . . . . . . . . . . . . . . =
. . . . . . .  22



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   11. References  . . . . . . . . . . . . . . . . . . =
. . . . . . .  23
     11.1.  Normative References . . . . . . . . . . =
. . . . . . . .  23
     11.2.  Informative References . . . . . . . . . =
. . . . . . . .  24
   Appendix A.  ChangeLog  . . . . . . . . . . . . . . =
. . . . . . .  26
   Appendix B.  Changes Needed on a software driver 802=
.11a to
                become a                     802.11-OCB driver . . .  28
   Appendix C.  Design Considerations  . . . . . . . . =
. . . . . . .  30
     C.1.  Vehicle ID  . . . . . . . . . . . . . . . =
. . . . . . . .  30
     C.2.  Reliability Requirements  . . . . . . . . =
. . . . . . . .  30
     C.3.  Multiple interfaces . . . . . . . . . . . =
. . . . . . . .  31
     C.4.  MAC Address Generation  . . . . . . . . . =
. . . . . . . .  32
   Appendix D.  IEEE 802.11 Messages Transmitted in OCB=
 mode . . . .  32
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  32


1.  Introduction


   This document describes the transmission of IPv6 packets on IEEE Std
   802.11 OCB networks (earlier known as 802.11p).  





[S=
ri] Please add a reference to the IEEE specification that defines the OCB m=
ode. 








This involves=
 the
   layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with
   an LLC layer).  Compared to running IPv6 over the Ethernet MAC layer,
   there is no modification required to the standards: IPv6 works fine
   directly over 802.11 OCB too (with an LLC layer).

   The term "802.11p" is an earlier definition.  As of year 2012,=
 the
   behaviour of "802.11p" networks has been rolled in the documen=
t IEEE
   Std 802.11-2012.  In this document the term 802.11p disappears.
   Instead, each 802.11p feature is conditioned by a flag in the
   Management Information Base.  That flag is named "OCBActivated"=
;.
   Whenever OCBActivated is set to true the feature it relates to
   represents an earlier 802.11p feature.  For example, an 802.11
   STAtion operating outside the context of a basic service set has the
   OCBActivated flag set.  Such a station, when it has the flag set, it
   uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.

   In the following text we use the term "802.11p" to mean 802.11=
-2012
   OCB.

   The IPv6 network layer operates on 802.11 OCB in the same manner as
   it operates on 802.11 WiFi, with a few particular exceptions.  The
   IPv6 network layer operates on WiFi by involving an Ethernet
   Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers
   to Ethernet II headers.  The operation of IP on Ethernet is described
   in [RFC1=
042] and [RFC2464]. =
 The situation of IPv6 networking layer
   on Ethernet Adaptation Layer is illustrated below:







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                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+
                 |                 IPv6                  |
                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+
                 |       Ethernet Adaptation Layer       |
                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi MAC           |
                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi PHY           |
                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+


   (in the above figure, a WiFi profile is represented; this is used
   also for OCB profile.)

   A more theoretical and detailed view of layer stacking, and
   interfaces between the IP layer and 802.11 OCB layers, is illustrated
   below.  The IP layer operates on top of the EtherType Protocol
   Discrimination (EPD); this Discrimination layer is described in IEEE
   Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP
   (Link Layer Control Service Accesss Point).


           +-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+
           |                 IPv6                  |
           +-+-+-+-+-+-{            }+-+-&#=
43;-+-+-+-+-+
                       {   LLC_SAP  }                 802.11 OCB
           +-+-+-+-+-+-{            }+-+-&#=
43;-+-+-+-+-+  Boundary
           |            EPD          |       |     |
           |                         | MLME  |     |
           +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   =
|
           |      MAC Sublayer       |       |     |  802.11 OCB
           |     and ch. coord.      |       | SME |  Services
           +-+-+-{   PHY_SAP  }+-+-+-+-+-&#=
43;-+-|     |
           |                         | PLME  |     |
           |            PHY Layer    |   PLME_SAP  |
           +-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+


   In addition to the description of interface between IP and MAC using
   "Ethernet Adaptation Layer" and "Ethernet Protocol Discri=
mination
   (EPD)" it is worth mentioning that SNAP [RFC1042] is used to carry
   the IPv6 Ethertype.

   However, there may be some deployment considerations helping optimize
   the performances of running IPv6 over 802.11-OCB (e.g. in the case of
   handovers between 802.11 OCB-enabled access routers, or the
   consideration of using the IP security layer [RFC4301]).




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   There are currently no specifications for handover between OCB links
   since these are currently specified as LLC-1 links (i.e.
   connectionless).  Any handovers must be performed above the Data Link
   Layer.  Also, while there is no encryption applied below the network
   layer using 802.11p, 1609.2 [ieee1609.2] does pr=
ovide security
   services for applications to use so that there can easily be data
   security over the air without invoking IPsec.

   We briefly introduce the vehicular communication scenarios where IEEE
   802.11-OCB links are used. 





[Sri] I have not seen much discussion on the link / communicatio=
n assumptions. 








 This is foll=
owed by a description of
   differences in specification terms, between 802.11 OCB and
   802.11a/b/g/n (and the same differences expressed in terms of
   requirements to software implementation are listed in Ap=
pendix B.)

   The document then concentrates on the parameters of layering IP over
   802.11 OCB as over Ethernet: value of MTU, the contents of Frame
   Format, the rules for forming Interface Identifiers, the mechanism
   for Address Mapping and for State-less Address Auto-configuration.
   These are precisely the same as IPv6 over Ethernet [RFC2464].

   As an example, these characteristics of layering IPv6 straight over
   LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet
   captured over a 802.11 OCB link; this is described in the section
   Section 6.

   A couple of points can be considered as different, although they are
   not required in order to have a working implementation of IPv6-over-
   802.11-OCB.  These points are consequences of the OCB operation which
   is particular to 802.11 OCB (Outside the Context of a BSS).  First,
   the handovers between OCB links need specific behaviour for IP Router
   Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of
   higher layer messages such as the 'Basic Safety Message' (in the US)
   or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE
   Routing Advertisement'; second, the IP security mechanisms are
   necessary, since OCB means that 802.11 is stripped of all 802.11
   link-layer security; a small additional security aspect which is
   shared between 802.11 OCB and other 802.11 links is the privacy
   concerns related to the address formation mechanisms.

   In the published literature, many documents describe aspects related
   to running IPv6 over 802.11 OCB:
   [I-D.jeong-ipwave-=
vehicular-networking-survey].


2.  Terminology


   The key words "MUST", "MUST NOT", "REQUIRED&quo=
t;, "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", &qu=
ot;MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].



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   RSU: Road Side Unit.  A computer equipped with at least one IEEE
   802.11 interface operated in OCB mode.  This definition applies to
   this document.  An RSU may be connected to the Internet, and may be
   equipped with additional wired or wireless network interfaces running
   IP.  An RSU MAY be an IP Router.






[S=
ri] RSU can be compared to an 802.11 access point; Or, WTP as defined in CA=
PWAP specification, RFC5415.



Perhaps. reph=
rase as below?:





"RSU: Road Side Unit. Its a wireless te=
rmination point (WTP), as defined in RFC5415 with one key difference, where=
 the wireless physical and the mac layer is configured to operate in =
802.11 OCB mode.  The RSU communicates with the On board Unit (OBU) in =
the vehicle over 802.11 wireless link operating in OCB mode.=94 








** Also, since you are def=
ining the RSU term, should you also not define OBU (On board Unit) in the v=
ehicle which is the entity on the other end of the link? =93RSU ----802.11-=
OCB=97=97OBU=94 ? May be introduce the OCB definition separately, just as y=
ou did with RSU, and show the communication link as 802.11-OCB.






   OCB: outsi=
de the context of a basic service set (BSS): A mode of
   operation in which a STA is not a member of a BSS and does not
   utilize IEEE Std 802.11 authentication, association, or data
   confidentiality.

   802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is
   flagged by "dot11OCBActivated".  This means: IEEE 802.11e for =
quality
   of service; 802.11j-2004 for half-clocked operations; and (what was
   known earlier as) 802.11p for operation in the 5.9 GHz band and in
   mode OCB.






[Sri] The text starting with. =93This means=94 is not clear=
 to me. Does it 802.11e is supported with 802.11OCB mode. Please clarify






3.  Communication Scenarios where IEEE 802.=
11 OCB Links are Used


   The IEEE 802.11 OCB Networks are used for vehicular communications,
   as 'Wireless Access in Vehicular Environments'.  The IP communication
   scenarios for these environments have been described in several
   documents, among which we refer the reader to one recently updated
   [I-D.petrescu-its-scenarios-req=
s], about scenarios and requirements
   for IP in Intelligent Transportation Systems.






[Sri] You can do bit more justice to this section. 
Explain the link model.  =93STA ----802.11-OCB=97=97STA=94. Then =
talk about the applicability in Vehicular networks, with STA's as RSU and O=
CB.


You may also want to talk =
about, how links get formed/terminated; how nodes peer/discover and how mob=
ility works ..etc.  While 802.11-OCB is clearly specified and the use of IP=
v6 over such link is also not radically new, but the operating environment =
which is vehicular brings many new things. That description is not present =
any where.





4.  Aspects introduced by the OCB mode to 8=
02.11


   In the IEEE 802.11 OCB mode, all nodes in the wireless range can
   directly communicate with each other without authentication/
   association procedures.  Briefly, the IEEE 802.11 OCB mode has the
   following properties:








[Sri] Can you add some tex=
t on how nodes (ST1 and STA2) discover each other on such links supporting =
802.11 OCB mode.


   o  The use=
 by each node of a 'wildcard' BSSID (i.e., each bit of the
      BSSID is set to 1)

   o  No IEEE 802.11 Beacon frames transmitted

   o  No authentication required

   o  No association needed

   o  No encryption provided





[Sri] Can you clarify what you mean when you say =93N=
o xxx required=94 / =93No xxx=
 needed=94  for the above capabilities.  What does =93needed=94 or =93=
required=94 mean?  Does it m=
ean, =93Authentication", =93Association" and =93Encryption=94 is =
optional on this link, or that its not supported on 802.11 OCB links.  





   o  Flag do=
t11OCBActivated set to true

   The following message exchange diagram illustrates a comparison
   between traditional 802.11 and 802.11 in OCB mode.  The 'Data'



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   messages can be IP messages such as the messages used in Stateless or
   Stateful Address Auto-Configuration, or other IP messages.  








[Sri] Lets separate the discussion on IP Address configuration using SLA=
AC/DHCP on such links from the above description. The Data packets here can=
 be application packets such as HTTP or other packets. May be additional di=
scussion is needed on the IP address configuration on 802.11-OCB links. 








Other
   802.11 management and control frames (non IP) may be transmitted, as
   specified in the 802.11 standard.  For information, the names of
   these messages as currently specified by the 802.11 standard are
   listed in Appendix D.


















     STA     =
               AP              STA1                   STA2
     |                      |               |                      |
     |<------ Beacon -------|               |<------ Data -------->=
;|
     |                      |               |                      |
     |---- Probe Req. ----->|               |<------ Data -------->=
;|
     |<--- Probe Res. ------|               |                      |
     |                      |               |<------ Data -------->|
     |---- Auth Req. ------>|               |                      |
     |<--- Auth Res. -------|               |<------ Data -------->=
;|
     |                      |               |                      |
     |---- Asso Req. ------>|               |<------ Data -------->=
;|
     |<--- Asso Res. -------|               |                      |
     |                      |               |<------ Data -------->|
     |<------ Data -------->|               |                      |
     |<------ Data -------->|               |<------ Data --------=
>|

    (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode


   The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010
   [ieee802.11p-2010] as an amendment to IEEE=
 Std 802.11 (TM) -2007,
   titled "Amendment 6: Wireless Access in Vehicular Environments"=
;.
   Since then, this amendment has been included in IEEE 802.11(TM)-2012
   [ieee802.11-2012], titled "IEEE Standa=
rd for Information technology--
   Telecommunications and information exchange between systems Local and
   metropolitan area networks--Specific requirements Part 11: Wireless
   LAN Medium Access Control (MAC) and Physical Layer (PHY)
   Specifications"; the modifications are diffused throughout various
   sections (e.g. the Time Advertisement message described in the
   earlier 802.11 (TM) p amendment is now described in section 'Frame
   formats', and the operation outside the context of a BSS described in
   section 'MLME').

   In document 802.11-2012, specifically anything referring
   "OCBActivated", or "outside the context of a basic servic=
e set" is
   actually referring to the 802.11p aspects introduced to 802.11.  Note
   that in earlier 802.11p documents the term "OCBEnabled" was us=
ed
   instead of te current "OCBActivated".





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   In order to delineate the aspects introduced by 802.11 OCB to 802.11,
   we refer to the earlier [ieee802.11p-2010]=
.  The amendment is
   concerned with vehicular communications, where the wireless link is
   similar to that of Wireless LAN (using a PHY layer specified by
   802.11a/b/g/n), but which needs to cope with the high mobility factor
   inherent in scenarios of communications between moving vehicles, and
   between vehicles and fixed infrastructure deployed along roads.
   While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is
   concerned more with MAC modifications, and a little with PHY
   modifications; the others are mainly about PHY modifications.  It is
   possible in practice to combine a 'p' MAC with an 'a' PHY by
   operating outside the context of a BSS with OFDM at 5.4GHz.

   The 802.11 OCB links are specified to be compatible as much as
   possible with the behaviour of 802.11a/b/g/n and future generation
   IEEE WLAN links.  From the IP perspective, an 802.11 OCB MAC layer
   offers practically the same interface to IP as the WiFi and Ethernet
   layers do (802.11a/b/g/n and 802.3).






[Sri] A packet sent from a vehicle=92s OBU is received by a sing=
le RSU, or multiple RSU=92s? How does the link-layer resolution happen?





   To support=
 this similarity statement (IPv6 is layered on top of LLC
   on top of 802.11 OCB similarly as on top of LLC on top of
   802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to
   analyze the differences between 802.11 OCB and 802.11 specifications.
   Whereas the 802.11p amendment specifies relatively complex and
   numerous changes to the MAC layer (and very little to the PHY layer),
   we note there are only a few characteristics which may be important
   for an implementation transmitting IPv6 packets on 802.11 OCB links.

   In the list below, the only 802.11 OCB fundamental points which
   influence IPv6 are the OCB operation and the 12Mbit/s maximum which
   may be afforded by the IPv6 applications.






[Sri] I am really not sure how link throughput (12Mbp=
s) relates to "IPv6 support on OCB links".  








   o  Operati=
on Outside the Context of a BSS (OCB): the (earlier
      802.11p) 802.11-OCB links are operated without a Basic Service Set
      (BSS).  This means that the frames IEEE 802.11 Beacon, Association
      Request/Response, Authentication Request/Response, and similar,
      are not used.  The used identifier of BSS (BSSID) has a
      hexadecimal value always 0xffffffffffff (48 '1' bits, represented
      as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'
      BSSID), as opposed to an arbitrary BSSID value set by
      administrator (e.g.  'My-Home-AccessPoint').  The OCB operation -
      namely the lack of beacon-based scanning and lack of
      authentication - has a potentially strong impact on the use of the
      Mobile IPv6 protocol [RFC6275] and on the protocols for IP layer
      security [RFC4301].






[Sri] The document till now has been arguing heavily =
on how IPv6 operates so naturally on these links and now I see discussion o=
n =93Impact to a high-level protocol such as MIPv6=94. You may want t=
o fix the earlier text. In any case,  the absence of link-layer security pr=
actically impacts every application, not just MIPv6.  Also, MIPv6 does not =
make any assumptions on the link-layer security.  Also, the the 0xFF-FF-FF-=
FF-FF-FF as the BSSID, makes the messages readable by all other RSU=92s in =
proximity. I think the discussion on the nature of the link, who all see=92=
s the messages.. how L2 addresses are resolved is not explained clearly. 











   o  Timing =
Advertisement: is a new message defined in 802.11-OCB,
      which does not exist in 802.11a/b/g/n.  This message is used by



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      stations to inform other stations about the value of time.  It is
      similar to the time as delivered by a GNSS system (Galileo, GPS,
      ...) or by a cellular system.  This message is optional for
      implementation.  At the date of writing, an experienced reviewer
      considers that currently no field testing has used this message.
      Another implementor considers this feature implemented in an
      initial manner.  In the future, it is speculated that this message
      may be useful for very simple devices which may not have their own
      hardware source of time (Galileo, GPS, cellular network), or by
      vehicular devices situated in areas not covered by such network
      (in tunnels, underground, outdoors but shaded by foliage or
      buildings, in remote areas, etc.)






[Sri] The first part explaining Timing Advertisement messag=
es is great, but the rest of the commentary is unnecessary and not needed. =
We don=92t speculate the protocol adoption success in IETF specifications, =
or about the experience level of the =93reviewer" :)








   o  Frequen=
cy range: this is a characteristic of the PHY layer, with
      almost no impact to the interface between MAC and IP.  However, it
      is worth considering that the frequency range is regulated by a
      regional authority (ARCEP, ETSI, FCC, etc.); as part of the
      regulation process, specific applications are associated with
      specific frequency ranges.  In the case of 802.11-OCB, the
      regulator associates a set of frequency ranges, or slots within a
      band, to the use of applications of vehicular communications, in a
      band known as "5.9GHz".  This band is "5.9GHz" wh=
ich is different
      from the bands "2.4GHz" or "5GHz" used by Wireles=
s LAN.  However,
      as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz&quo=
t;
      bands is exempt from owning a license in EU (in US the 5.9GHz is a
      licensed band of spectrum; for the the fixed infrastructure an
      explicit FCC autorization is required; for an onboard device a
      'licensed-by-rule' concept applies: rule certification conformity
      is required); however technical conditions are different than
      those of the bands "2.4GHz" or "5GHz".  On one ha=
nd, the allowed
      power levels, and implicitly the maximum allowed distance between
      vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20
      dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum
      distance of approximately 1km, compared to approximately 50m.  On
      the other hand, specific conditions related to congestion
      avoidance, jamming avoidance, and radar detection are imposed on
      the use of DSRC (in US) and on the use of frequencies for
      Intelligent Transportation Systems (in EU), compared to Wireless
      LAN (802.11a/b/g/n).

   o  Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB,
      as opposed to IPv6 not being prohibited on any channel on which
      802.11a/b/g/n runs:

      *  Some channels are reserved for safety communications; the IPv6
         packets should not be sent on these channels.





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      *  At the time of writing, the prohibition is explicit at higher
         layer protocols providing services to the application; these
         higher layer protocols are specified in IEEE 1609 documents.

      *  National or regional specifications and regulations specify the
         use of different channels; these regulations must be followed.

   o  'Half-rate' encoding: as the frequency range, this parameter is
      related to PHY, and thus has not much impact on the interface
      between the IP layer and the MAC layer.

   o  In vehicular communications using 802.11-OCB links, there are
      strong privacy requirements with respect to addressing.  While the
      802.11-OCB standard does not specify anything in particular with
      respect to MAC addresses, in these settings there exists a strong
      need for dynamic change of these addresses (as opposed to the non-
      vehicular settings - real wall protection - where fixed MAC
      addresses do not currently pose some privacy risks).  This is
      further described in section Section 7.  A relevan=
t function is
      described in IEEE 1609.3-2016 [ieee1609.3], c=
lause 5.5.1 and IEEE
      1609.4-2016 [ieee1609.4], clause 6.7.






   Other aspe=
cts particular to 802.11-OCB which are also particular to
   802.11 (e.g. the 'hidden node' operation) may have an influence on
   the use of transmission of IPv6 packets on 802.11-OCB networks.  The
   subnet structure which may be assumed in 802.11-OCB networks is
   strongly influenced by the mobility of vehicles.






[Sri] Per my earlier comment, the link model, addressing ..=
etc needs to be explained in more detail. It is not clear what exactly the =
=93subnet structure=94 that is assumed in 802.11-OCB.





5.  Layering of IPv6 over 802.11-OCB as ove=
r Ethernet



5.1.  Maximum Transmission U=
nit (MTU)


   The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is
   the same value as IPv6 packets on Ethernet links, as specified in
   [RFC2464].  This valu=
e of the MTU respects the recommendation that
   every link in the Internet must have a minimum MTU of 1280 octets
   (stated in [RFC2460], a=
nd the recommendations therein, especially
   with respect to fragmentation).  If IPv6 packets of size larger than
   1500 bytes are sent on an 802.11-OCB interface card then the IP stack
   will fragment.  In case there are IP fragments, the field "Sequence
   number" of the 802.11 Data header containing the IP fragment field =
is
   increased.

   Non-IP packets such as WAVE Short Message Protocol (WSMP) can be
   delivered on 802.11-OCB links.  Specifications of these packets are
   out of scope of this document, and do not impose any limit on the MTU
   size, allowing an arbitrary number of 'containers'.  Non-IP packets
   such as ETSI 'geonet' packets have an MTU of 1492 bytes.



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   The Equivalent Transmit Time on Channel is a concept that may be used
   as an alternative to the MTU concept.  A rate of transmission may be
   specified as well.  The ETTC, rate and MTU may be in direct
   relationship.



[Sri] The last paragraph needs some additional context. Did=
 802.11-OCB introduce ETTC concept?  











5.2.  Frame Format


   IP packets are transmitted over 802.11-OCB as standard Ethernet
   packets.  As with all 802.11 frames, an Ethernet adaptation layer is
   used with 802.11-OCB as well.  This Ethernet Adaptation Layer
   performing 802.11-to-Ethernet is described in Section=
 5.2.1.  The
   Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD,
   or otherwise #86DD).

   The Frame format for transmitting IPv6 on 802.11-OCB networks is the
   same as transmitting IPv6 on Ethernet networks, and is described in
   section 3=
 of [RFC2464].  The frame format for transmitting IPv6
   packets over Ethernet is illustrated below:


                    0                   1
                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    |          Destination          |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    |             Source            |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    |             IPv6              |
                    +-                             -+
                    |            header             |
                    +-                             -+
                    |             and               |
                    +-                             -+
                    /            payload ...        /
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    (Each tic mark represents one bit.)





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   Ethernet II Fields:

   Destination Ethernet Address
      the MAC destination address.

   Source Ethernet Address
      the MAC source address.

   1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
      binary representation of the EtherType value 0x86DD.

   IPv6 header and payload
      the IPv6 packet containing IPv6 header and payload.


5.2.1.  Ethernet Adaptat=
ion Layer


   In general, an 'adaptation' layer is inserted between a MAC layer and
   the Networking layer.  This is used to transform some parameters
   between their form expected by the IP stack and the form provided by
   the MAC layer.  For example, an 802.15.4 adaptation layer may perform
   fragmentation and reassembly operations on a MAC whose maximum Packet
   Data Unit size is smaller than the minimum MTU recognized by the IPv6
   Networking layer.  Other examples involve link-layer address
   transformation, packet header insertion/removal, and so on.

   An Ethernet Adaptation Layer makes an 802.11 MAC look to IP
   Networking layer as a more traditional Ethernet layer.  At reception,
   this layer takes as input the IEEE 802.11 Data Header and the
   Logical-Link Layer Control Header and produces an Ethernet II Header.
   At sending, the reverse operation is performed.


 +--------------------+------------+-------------+---------=
+-----------+
 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer|
 +--------------------+------------+-------------+---------=
+-----------+
  \                               /                         \         /
    -----------------------------                             --------
                   ^---------------------------------------------/
                   |
           802.11-to-Ethernet Adaptation Layer
                   |
                   v
 +---------------------+-------------+---------+
 | Ethernet II Header  | IPv6 Header | Payload |
 +---------------------+-------------+---------+






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   The Receiver and Transmitter Address fields in the 802.11 Data Header
   contain the same values as the Destination and the Source Address
   fields in the Ethernet II Header, respectively.  The value of the
   Type field in the LLC Header is the same as the value of the Type
   field in the Ethernet II Header.

   The ".11 Trailer" contains solely a 4-byte Frame Check Sequenc=
e.

   The Ethernet Adaptation Layer performs operations in relation to IP
   fragmentation and MTU.  One of these operations is briefly described
   in section Section 5.1.

   In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11
   Data" or alternatively as "IEEE 802.11 QoS Data", as illu=
strated in
   the following figure:


+--------------------+-------------+-------------+---------=
+-----------+
| 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------=
+-----------+

or

+--------------------+-------------+-------------+---------=
+-----------+
| 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------=
+-----------+


   The distinction between the two formats is given by the value of the
   field "Type/Subtype".  The value of the field "Type/Subty=
pe" in the
   802.11 Data header is 0x0020.  The value of the field "Type/Subtype=
"
   in the 802.11 QoS header is 0x0028.

   The mapping between qos-related fields in the IPv6 header (e.g.
   "Traffic Class", "Flow label") and fields in the &qu=
ot;802.11 QoS Data
   Header" (e.g.  "QoS Control") are not specified in this d=
ocument.
   Guidance for a potential mapping is provided in
   [I-D.ietf-tsvwg-ieee-802-11], al=
though it is not specific to OCB
   mode.









[Sri] The applicability of the QoS mapping draft to 802.11-=
OCB needs further investigation, IMO.











5.3.  Link-Local Addresses


   The link-local address of an 802.11-OCB interface is formed in the
   same manner as on an Ethernet interface.  This manner is described in
   section 5=
 of [RFC2464].





[Sri] Does this go against=
 the 8064 recommendation on Interface identifier generation?<=
/pre>
=
May be R=
FC7217 for interface identifier generation in conjunction with the link-loc=
al address generation per RFC2464





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5.4.  Address Mapping


   For unicast as for multicast, there is no change from the unicast and
   multicast address mapping format of Ethernet interfaces, as defined
   by sections 6 and 7 of [RFC2464].









[Sri] RFC6085 specified mapping is also relevant; If =
the communication peers are aware that there is only one peer, it should ap=
ply 6085 specified mapping. That mode is relevant for 802.11-OCB types link=
s as well.








5.4.1.  Address Mapping -- Unicast<=
/h4>

   The procedure for mapping IPv6 unicast addresses into Ethernet link-
   layer addresses is described in [R=
FC4861].  The Source/Target Link-
   layer Address option has the following form when the link-layer is
   Ethernet.



[Sri] I thought, mapping of IPv6 unicast addresses to Ether=
net link-layer addresses is specified in section 6, of RFC2464 and not in R=
FC4861.











             =
         0                   1
                      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+
                     |     Type      |    Length     |
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+
                     |                               |
                     +-          Ethernet           -+
                     |                               |
                     +-           Address           -+
                     |                               |
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+


   Option fields:

   Type
      1 for Source Link-layer address.
      2 for Target Link-layer address.

   Length
      1 (in units of 8 octets).

   Ethernet Address
      The 48 bit Ethernet IEEE 802 address, in canonical bit order.


5.4.2.  Address Mapping =
-- Multicast


   IPv6 protocols often make use of IPv6 multicast addresses in the
   destination field of IPv6 headers.  For example, an ICMPv6 link-
   scoped Neighbor Advertisement is sent to the IPv6 address ff02::1
   denoted "all-nodes" address.  When transmitting these packets =
on
   802.11-OCB links it is necessary to map the IPv6 address to a MAC
   address.




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   The same mapping requirement applies to the link-scoped multicast
   addresses of other IPv6 protocols as well.  In DHCPv6, the
   "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OS=
PF the
   "All_SPF_Routers" IPv6 multicast address ff02::5, need to be m=
apped
   on a multicast MAC address.

   An IPv6 packet with a multicast destination address DST, consisting
   of the sixteen octets DST[1] through DST[16], is transmitted to the
   IEEE 802.11-OCB MAC multicast address whose first two octets are the
   value 0x3333 and whose last four octets are the last four octets of
   DST.



<=
font face=3D"Calibri,sans-serif">[Sri] Ple=
ase add a reference to Section 7, RFC4861 and also RFC6085. In general, for=
 both unicast and multicast, you may want to clearly say that this is per t=
he existing specs and duplicated here for convenience. 
=






             =
        +-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+
                     |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+
                     |   DST[13]     |   DST[14]     |
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+
                     |   DST[15]     |   DST[16]     |
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+


   A Group ID TBD of length 112bits may be requested from IANA; this
   Group ID signifies "All 80211OCB Interfaces Address".  Only th=
e least
   32 significant bits of this "All 80211OCB Interfaces Address" =
will be
   mapped to and from a MAC multicast address.

   Transmitting IPv6 packets to multicast destinations over 802.11 links
   proved to have some performance issues
   [I-D.perkins-intarea-mult=
icast-ieee802].  These issues may be
   exacerbated in OCB mode.  Solutions for these problems should
   consider the OCB mode of operation.


5.5.  Stateless Autoconfigur=
ation


   The Interface Identifier for an 802.11-OCB interface is formed using
   the same rules as the Interface Identifier for an Ethernet interface;
   this is described in section 4 of [RFC2464].  No changes are needed,
   but some care must be taken when considering the use of the SLAAC
   procedure.








[Sri] Per my earlier comment, please refer to the current r=
ecommendation on interface-identifier generation and its use in link-local,=
 global or other addresses.


   The bits in the the interface identifier have no generic meaning and
   the identifier should be treated as an opaque value.  The bits
   'Universal' and 'Group' in the identifier of an 802.11-OCB interface
   are significant, as this is an IEEE link-layer address.  The details
   of this significance are described in [I-D.ietf-6m=
an-ug].





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   As with all Ethernet and 802.11 interface identifiers ([RFC7721]),
   the identifier of an 802.11-OCB interface may involve privacy risks.
   A vehicle embarking an On-Board Unit whose egress interface is
   802.11-OCB may expose itself to eavesdropping and subsequent
   correlation of data; this may reveal data considered private by the
   vehicle owner; there is a risk of being tracked; see the privacy
   considerations described in Appendix C.






<=
font face=3D"Calibri,sans-serif">[Sri] I t=
hink there are other security issues here; the absence of link-layer securi=
ty opens up Mac-spoofing and IP address hijacking.  That should be mentione=
d.






   If stable =
Interface Identifiers are needed in order to form IPv6
   addresses on 802.11-OCB links, it is recommended to follow the
   recommendation in [I-D.ietf-6man-def=
ault-iids].


5.6.  Subnet Structure
<=
/span>

   The 802.11 networks in OCB mode may be considered as 'ad-hoc'
   networks.  The addressing model for such networks is described in
   [RFC5889].






[Sri] Per my earlier comment, there is no system level view=
 of the network where 802.11-OCB links are used. So, in the absence of such=
 discussion So, I am not sure what part of RFC5889 is applicable here=
. For example, link-local addresses may just work fine. 








6.  Example IPv6 Packet captured over a IEE=
E 802.11-OCB link


   We remind that a main goal of this document is to make the case that
   IPv6 works fine over 802.11-OCB networks.  Consequently, this section
   is an illustration of this concept and thus can help the implementer
   when it comes to running IPv6 over IEEE 802.11-OCB.  By way of
   example we show that there is no modification in the headers when
   transmitted over 802.11-OCB networks - they are transmitted like any
   other 802.11 and Ethernet packets.

   We describe an experiment of capturing an IPv6 packet on an
   802.11-OCB link.  In this experiment, the packet is an IPv6 Router
   Advertisement.  This packet is emitted by a Router on its 802.11-OCB
   interface.  The packet is captured on the Host, using a network
   protocol analyzer (e.g.  Wireshark); the capture is performed in two
   different modes: direct mode and 'monitor' mode.  The topology used
   during the capture is depicted below.


              +--------+                                +------=
-+
              |        |        802.11-OCB Link         |       |
           ---| Router |--------------------------------| Host  |
              |        |                                |       |
              +--------+                                +------=
-+


   During several capture operations running from a few moments to
   several hours, no message relevant to the BSSID contexts were
   captured (no Association Request/Response, Authentication Req/Resp,




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   Beacon).  This shows that the operation of 802.11-OCB is outside the
   context of a BSSID.

   Overall, the captured message is identical with a capture of an IPv6
   packet emitted on a 802.11b interface.  The contents are precisely
   similar.






[Sri] I suggest moving this discussion under the section =
=93Implementation Status=94, which will eventually be removed from the RFC.=
 There is nothing new here. This are details on experimentation. But, if yo=
u think there is some useful information  such as discussion on Capture mod=
e ..etc, you may want to move this entire section to Appendix. Implementors=
 may use these tools for verification.











6.1.  Capture in Monitor Mode


   The IPv6 RA packet captured in monitor mode is illustrated below.
   The radio tap header provides more flexibility for reporting the
   characteristics of frames.  The Radiotap Header is prepended by this
   particular stack and operating system on the Host machine to the RA
   packet received from the network (the Radiotap Header is not present
   on the air).  The implementation-dependent Radiotap Header is useful
   for piggybacking PHY information from the chip's registers as data in
   a packet understandable by userland applications using Socket
   interfaces (the PHY interface can be, for example: power levels, data
   rate, ratio of signal to noise).

   The packet present on the air is formed by IEEE 802.11 Data Header,
   Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.



     Radiotap Header v0
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |Header Revision|  Header Pad   |    Header length              |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                         Present flags                         |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     | Data Rate     |             Pad                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+

     IEEE 802.11 Data Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |  Type/Subtype and Frame Ctrl  |          Duration             |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                      Receiver Address...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ... Receiver Address           |      Transmitter Address...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ... Transmitter Address                                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                            BSS Id...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ... BSS Id                     |  Frag Number and Seq Number   |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+



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     Logical-Link Control Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |      DSAP   |I|     SSAP    |C| Control field | Org. code...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ... Organizational Code        |             Type              |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +                         Source Address                        &#=
43;
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +                      Destination Address                      &#=
43;
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-


   The value of the Data Rate field in the Radiotap header is set to 6
   Mb/s.  This indicates the rate at which this RA was received.





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   The value of the Transmitter address in the IEEE 802.11 Data Header
   is set to a 48bit value.  The value of the destination address is
   33:33:00:00:00:1 (all-nodes multicast address).  The value of the BSS
   Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network
   protocol analyzer as being "broadcast".  The Fragment number a=
nd
   sequence number fields are together set to 0x90C6.

   The value of the Organization Code field in the Logical-Link Control
   Header is set to 0x0, recognized as "Encapsulated Ethernet".  =
The
   value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise
   #86DD), recognized as "IPv6".

   A Router Advertisement is periodically sent by the router to
   multicast group address ff02::1.  It is an icmp packet type 134.  The
   IPv6 Neighbor Discovery's Router Advertisement message contains an
   8-bit field reserved for single-bit flags, as described in [RFC4861].

   The IPv6 header contains the link local address of the router
   (source) configured via EUI-64 algorithm, and destination address set
   to ff02::1.  Recent versions of network protocol analyzers (e.g.
   Wireshark) provide additional informations for an IP address, if a
   geolocalization database is present.  In this example, the
   geolocalization database is absent, and the "GeoIP" informatio=
n is
   set to unknown for both source and destination addresses (although
   the IPv6 source and destination addresses are set to useful values).
   This "GeoIP" can be a useful information to look up the city,
   country, AS number, and other information for an IP address.





[Sri] Not sur=
e, why all of this text should be in the specification. 




   The Ethern=
et Type field in the logical-link control header is set to
   0x86dd which indicates that the frame transports an IPv6 packet.  In
   the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
   which is he corresponding multicast MAC address.  The BSS id is a
   broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link
   duration between vehicles and the roadside infrastructure, there is
   no need in IEEE 802.11-OCB to wait for the completion of association
   and authentication procedures before exchanging data.  IEEE
   802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)
   and may start communicating as soon as they arrive on the
   communication channel.


6.2.  Capture in Normal Mode=



   The same IPv6 Router Advertisement packet described above (monitor
   mode) is captured on the Host, in the Normal mode, and depicted
   below.






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     Ethernet II Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                       Destination...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ...Destination                 |           Source...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ...Source                                                      |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |          Type                 |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +                         Source Address                        &#=
43;
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +                      Destination Address                      &#=
43;
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-





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   One notices that the Radiotap Header is not prepended, and that the
   IEEE 802.11 Data Header and the Logical-Link Control Headers are not
   present.  On another hand, a new header named Ethernet II Header is
   present.

   The Destination and Source addresses in the Ethernet II header
   contain the same values as the fields Receiver Address and
   Transmitter Address present in the IEEE 802.11 Data Header in the
   "monitor" mode capture.

   The value of the Type field in the Ethernet II header is 0x86DD
   (recognized as "IPv6"); this value is the same value as the va=
lue of
   the field Type in the Logical-Link Control Header in the "monitor&q=
uot;
   mode capture.

   The knowledgeable experimenter will no doubt notice the similarity of
   this Ethernet II Header with a capture in normal mode on a pure
   Ethernet cable interface.

   It may be interpreted that an Adaptation layer is inserted in a pure
   IEEE 802.11 MAC packets in the air, before delivering to the
   applications.  In detail, this adaptation layer may consist in
   elimination of the Radiotap, 802.11 and LLC headers and insertion of
   the Ethernet II header.  In this way, it can be stated that IPv6 runs
   naturally straight over LLC over the 802.11-OCB MAC layer, as shown
   by the use of the Type 0x86DD, and assuming an adaptation layer
   (adapting 802.11 LLC/MAC to Ethernet II header).


7.  Security Considerations
=


   Any security mechanism at the IP layer or above that may be carried
   out for the general case of IPv6 may also be carried out for IPv6
   operating over 802.11-OCB.






   802.11-OCB=
 does not provide any cryptographic protection, because it
   operates outside the context of a BSS (no Association Request/
   Response, no Challenge messages).  Any attacker can therefore just
   sit in the near range of vehicles, sniff the network (just set the
   interface card's frequency to the proper range) and perform attacks
   without needing to physically break any wall.  Such a link is way
   less protected than commonly used links (wired link or protected
   802.11).



[Sri] Per my earlier comme=
nt, there is more than one attack vector possible
1.) Absence of lin=
k-layer security and the potential for mac address spoofing <=
/pre>
=
2.) IP a=
ddress / Session hijacking 
3.) Data privacy per your text=







   At the IP =
layer, IPsec can be used to protect unicast communications,
   and SeND can be used for multicast communications. 





[Sri] IPSec c=
an be used for protecting both multicast or unicast communication; RFC-5374=
 with GDOI.











 If no protec=
tion
   is used by the IP layer, upper layers should be protected.
   Otherwise, the end-user or system should be warned about the risks
   they run.



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   As with all Ethernet and 802.11 interface identifiers, there may
   exist privacy risks in the use of 802.11-OCB interface identifiers.
   Moreover, in outdoors vehicular settings, the privacy risks are more
   important than in indoors settings.  New risks are induced by the
   possibility of attacker sniffers deployed along routes which listen
   for IP packets of vehicles passing by.  For this reason, in the
   802.11-OCB deployments, there is a strong necessity to use protection
   tools such as dynamically changing MAC addresses.  This may help
   mitigate privacy risks to a certain level.  On another hand, it may
   have an impact in the way typical IPv6 address auto-configuration is
   performed for vehicles (SLAAC would rely on MAC addresses amd would
   hence dynamically change the affected IP address), in the way the
   IPv6 Privacy addresses were used, and other effects.


8.  IANA Considerations



9.  Contributors


   Romain Kuntz contributed extensively about IPv6 handovers between
   links running outside the context of a BSS (802.11-OCB links).

   Tim Leinmueller contributed the idea of the use of IPv6 over
   802.11-OCB for distribution of certificates.

   Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey
   Voronov provided significant feedback on the experience of using IP
   messages over 802.11-OCB in initial trials.

   Michelle Wetterwald contributed extensively the MTU discussion,
   offered the ETSI ITS perspective, and reviewed other parts of the
   document.


10.  Acknowledgements


   The authors would like to thank Witold Klaudel, Ryuji Wakikawa,
   Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan
   Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray
   Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,
   Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,
   Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,
   Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and
   William Whyte.  Their valuable comments clarified certain issues and
   generally helped to improve the document.

   Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB
   drivers for linux and described how.





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   For the multicast discussion, the authors would like to thank Owen
   DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and
   participants to discussions in network working groups.

   The authours would like to thank participants to the Birds-of-
   a-Feather "Intelligent Transportation Systems" meetings held a=
t IETF
   in 2016.


11.  References



11.1.  Normative Reference=
s


   [I-D.ietf-6man-default-iids]
              Gont, F., Cooper, A., Thaler, D., and S. LIU,
              "Recommendation on Stable IPv6 Interface Identifiers&quo=
t;,
              draft-ietf-6man-default-iids-16 (work in progress),
              September 2016.

   [I-D.ietf-6=
man-ug]
              Carpenter, B. and S. Jiang, "Significance of IPv6
              Interface Identifiers", draft-ietf-6man-ug-06 (work in
              progress), December 2013.

   [I-D.ietf-tsvwg-ieee-802-11]
              Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE
              802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-06 (work =
in
              progress), August 2017.

   [RFC1042]  Postel, J. and=
 J. Reynolds, "Standard for the transmission
              of IP datagrams over IEEE 802 networks", STD 43, RFC 1042,
              DOI 10.17487/RFC1042, February 1988, <https://www.rfc-
              editor.or=
g/info/rfc1042>.

   [RFC2119]  Bradner, S., &=
quot;Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC =
2119,
              DOI 10.17487/RFC2119, March 1997, <https://www.rfc-
              editor.or=
g/info/rfc2119>.

   [RFC2460]  Deering, S. an=
d R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
              December 1998, <https://www.rfc-editor.org/info/rfc2460>.

   [RFC2464]  Crawford, M., =
"Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998,
              <https=
://www.rfc-editor.org/info/rfc2464>.






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   [RFC3963]  Devarapalli, V=
., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol=
",
              RFC 3963,=
 DOI 10.17487/RFC3963, January 2005,
              <https=
://www.rfc-editor.org/info/rfc3963>.

   [RFC4086]  Eastlake 3rd, =
D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security", BCP 106, RFC 4086,
              DOI 10.17487/RFC4086, June 2005, <https://www.rfc-
              editor.or=
g/info/rfc4086>.

   [RFC4301]  Kent, S. and K=
. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.

   [RFC4429]  Moore, N., &qu=
ot;Optimistic Duplicate Address Detection (DAD)
              for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006,
              <https=
://www.rfc-editor.org/info/rfc4429>.

   [RFC4861]  Narten, T., No=
rdmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007, <https://www.rfc-
              editor.or=
g/info/rfc4861>.

   [RFC5889]  Baccelli, E., =
Ed. and M. Townsley, Ed., "IP Addressing
              Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889,
              September 2010, <https://www.rfc-editor.org/info/rfc5889>.

   [RFC6275]  Perkins, C., E=
d., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
              2011, <https://www.rfc-editor.org/info/rfc6275>.

   [RFC6775]  Shelby, Z., Ed=
., Chakrabarti, S., Nordmark, E., and C.
              Bormann, "Neighbor Discovery Optimization for IPv6 over
              Low-Power Wireless Personal Area Networks (6LoWPANs)",
              RFC 6775,=
 DOI 10.17487/RFC6775, November 2012,
              <https=
://www.rfc-editor.org/info/rfc6775>.

   [RFC7721]  Cooper, A., Go=
nt, F., and D. Thaler, "Security and Privacy
              Considerations for IPv6 Address Generation Mechanisms",
              RFC 7721,=
 DOI 10.17487/RFC7721, March 2016,
              <https=
://www.rfc-editor.org/info/rfc7721>.


11.2.  Informative Referen=
ces









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   [fcc-cc]   "'Report an=
d Order, Before the Federal Communications
              Commission Washington, D.C. 20554', FCC 03-324, Released
              on February 10, 2004, document FCC-03-324A1.pdf, document
              freely available at URL
              http://=
www.its.dot.gov/exit/fcc_edocs.htm downloaded on
              October 17th, 2013.".

   [fcc-cc-172-184=
]
              "'Memorandum Opinion and Order, Before the Federal
              Communications Commission Washington, D.C. 20554', FCC
              06-10, Released on July 26, 2006, document FCC-
              06-110A1.pdf, document freely available at URL
              http://hraunfoss.fcc.gov/edocs_public/attachmatch/
              FCC-06-110A1.pdf downloaded on June 5th, 2014.".

   [I-D.jeong-ipwave-vehicular-ne=
tworking-survey]
              Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M.
              Wetterwald, "Survey on IP-based Vehicular Networking for
              Intelligent Transportation Systems", draf=
t-jeong-ipwave-
              vehicular-networking-survey-03 (work in pr=
ogress), June
              2017.

   [I-D.perkins-intarea-multicast-ieee802]
              Perkins, C., Stanley, D., Kumari, W., and J. Zuniga,
              "Multicast Considerations over IEEE 802 Wireless Media&q=
uot;,
              draft-perkins-intarea-multicast-ieee802-03 (work =
in
              progress), July 2017.

   [I-D.petrescu-its-scenarios-reqs]
              Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel,
              "Scenarios and Requirements for IP in Intelligent
              Transportation Systems", draft-petrescu-its-scenarios-=

              reqs-03 (work in progress), October 2013.

   [ieee1609.2]
              "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Acce=
ss
              in Vehicular Environments (WAVE) -- Security Services for
              Applications and Management Messages.  Example URL
              http=
://ieeexplore.ieee.org/document/7426684/ accessed on
              August 17th, 2017.".

   [ieee1609.3]
              "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Acce=
ss
              in Vehicular Environments (WAVE) -- Networking Services.
              Example URL http://ieeexplore.ieee.org/document/7458115/
              accessed on August 17th, 2017.".





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   [ieee1609.4]
              "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Acce=
ss
              in Vehicular Environments (WAVE) -- Multi-Channel
              Operation.  Example URL
              http=
://ieeexplore.ieee.org/document/7435228/ accessed on
              August 17th, 2017.".

   [ieee802.11-2=
012]
              "802.11-2012 - IEEE Standard for Information technology-=
-
              Telecommunications and information exchange between
              systems Local and metropolitan area networks--Specific
              requirements Part 11: Wireless LAN Medium Access Control
              (MAC) and Physical Layer (PHY) Specifications.  Downloaded
              on October 17th, 2013, from IEEE Standards, document
              freely available at URL
              http://standards.ieee.org/findstds/
              standard/802.11-2012.html retrieved on October 17th,
              2013.".

   [ieee802.11=
p-2010]
              "IEEE Std 802.11p (TM)-2010, IEEE Standard for Informati=
on
              Technology - Telecommunications and information exchange
              between systems - Local and metropolitan area networks -
              Specific requirements, Part 11: Wireless LAN Medium Access
              Control (MAC) and Physical Layer (PHY) Specifications,
              Amendment 6: Wireless Access in Vehicular Environments;
              document freely available at URL
              http://standards.ieee.org/getieee802/
              download/802.11p-2010.pdf retrieved on September 20th,
              2013.".


Appendix A.  ChangeLog


   The changes are listed in reverse chronological order, most recent
   changes appearing at the top of the list.

   From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf=
-ipwave-
   ipv6-over-80211ocb-04

   o  Removed a few informative references pointing to Dx draft IEEE
      1609 documents.

   o  Removed outdated informative references to ETSI documents.

   o  Added citations to IEEE 1609.2, .3 and .4-2016.

   o  Minor textual issues.




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   From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf=
-ipwave-
   ipv6-over-80211ocb-03

   o  Keep the previous text on multiple addresses, so remove talk about
      MIP6, NEMOv6 and MCoA.

   o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.

   o  Clarified the figure showing Infrastructure mode and OCB mode side
      by side.

   o  Added a reference to the IP Security Architecture RFC.

   o  Detailed the IPv6-per-channel prohibition paragraph which reflects
      the discussion at the last IETF IPWAVE WG meeting.

   o  Added section "Address Mapping -- Unicast".

   o  Added the ".11 Trailer" to pictures of 802.11 frames.

   o  Added text about SNAP carrying the Ethertype.

   o  New RSU definition allowing for it be both a Router and not
      necessarily a Router some times.

   o  Minor textual issues.

   From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf=
-ipwave-
   ipv6-over-80211ocb-02

   o  Replaced almost all occurences of 802.11p with 802.11-OCB, leaving
      only when explanation of evolution was necessary.

   o  Shortened by removing parameter details from a paragraph in the
      Introduction.

   o  Moved a reference from Normative to Informative.

   o  Added text in intro clarifying there is no handover spec at IEEE,
      and that 1609.2 does provide security services.

   o  Named the contents the fields of the EthernetII header (including
      the Ethertype bitstring).

   o  Improved relationship between two paragraphs describing the
      increase of the Sequence Number in 802.11 header upon IP
      fragmentation.




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   o  Added brief clarification of "tracking".

   From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf=
-ipwave-
   ipv6-over-80211ocb-01

   o  Introduced message exchange diagram illustrating differences
      between 802.11 and 802.11 in OCB mode.

   o  Introduced an appendix listing for information the set of 802.11
      messages that may be transmitted in OCB mode.

   o  Removed appendix sections "Privacy Requirements", "Aut=
hentication
      Requirements" and "Security Certificate Generation".

   o  Removed appendix section "Non IP Communications".

   o  Introductory phrase in the Security Considerations section.

   o  Improved the definition of "OCB".

   o  Introduced theoretical stacked layers about IPv6 and IEEE layers
      including EPD.

   o  Removed the appendix describing the details of prohibiting IPv6 on
      certain channels relevant to 802.11-OCB.

   o  Added a brief reference in the privacy text about a precise clause
      in IEEE 1609.3 and .4.

   o  Clarified the definition of a Road Side Unit.

   o  Removed the discussion about security of WSA (because is non-IP).

   o  Removed mentioning of the GeoNetworking discussion.

   o  Moved references to scientific articles to a separate 'overview'
      draft, and referred to it.


Appendix B.  Changes Needed o=
n a software driver 802.11a to become a

             802.11-OCB driver

   The 802.11p amendment modifies both the 802.11 stack's physical and
   MAC layers but all the induced modifications can be quite easily
   obtained by modifying an existing 802.11a ad-hoc stack.

   Conditions for a 802.11a hardware to be 802.11-OCB compliant:





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   o  The chip must support the frequency bands on which the regulator
      recommends the use of ITS communications, for example using IEEE
      802.11-OCB layer, in France: 5875MHz to 5925MHz.

   o  The chip must support the half-rate mode (the internal clock
      should be able to be divided by two).

   o  The chip transmit spectrum mask must be compliant to the "Transm=
it
      spectrum mask" from the IEEE 802.11p amendment (but experimental
      environments tolerate otherwise).

   o  The chip should be able to transmit up to 44.8 dBm when used by
      the US government in the United States, and up to 33 dBm in
      Europe; other regional conditions apply.

   Changes needed on the network stack in OCB mode:

   o  Physical layer:

      *  The chip must use the Orthogonal Frequency Multiple Access
         (OFDM) encoding mode.

      *  The chip must be set in half-mode rate mode (the internal clock
         frequency is divided by two).

      *  The chip must use dedicated channels and should allow the use
         of higher emission powers.  This may require modifications to
         the regulatory domains rules, if used by the kernel to enforce
         local specific restrictions.  Such modifications must respect
         the location-specific laws.

      MAC layer:

      *  All management frames (beacons, join, leave, and others)
         emission and reception must be disabled except for frames of
         subtype Action and Timing Advertisement (defined below).

      *  No encryption key or method must be used.

      *  Packet emission and reception must be performed as in ad-hoc
         mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).

      *  The functions related to joining a BSS (Association Request/
         Response) and for authentication (Authentication Request/Reply,
         Challenge) are not called.

      *  The beacon interval is always set to 0 (zero).




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      *  Timing Advertisement frames, defined in the amendment, should
         be supported.  The upper layer should be able to trigger such
         frames emission and to retrieve information contained in
         received Timing Advertisements.


Appendix C.  Design Considera=
tions


   The networks defined by 802.11-OCB are in many ways similar to other
   networks of the 802.11 family.  In theory, the encapsulation of IPv6
   over 802.11-OCB could be very similar to the operation of IPv6 over
   other networks of the 802.11 family.  However, the high mobility,
   strong link asymetry and very short connection makes the 802.11-OCB
   link significantly different from other 802.11 networks.  Also, the
   automotive applications have specific requirements for reliability,
   security and privacy, which further add to the particularity of the
   802.11-OCB link.


C.1.  Vehicle ID


   Automotive networks require the unique representation of each of
   their node.  Accordingly, a vehicle must be identified by at least
   one unique identifier.  The current specification at ETSI and at IEEE
   1609 identifies a vehicle by its MAC address uniquely obtained from
   the 802.11-OCB NIC.

   A MAC address uniquely obtained from a IEEE 802.11-OCB NIC
   implicitely generates multiple vehicle IDs in case of multiple
   802.11-OCB NICs.  A mechanims to uniquely identify a vehicle
   irrespectively to the different NICs and/or technologies is required.


C.2.  Reliability Requirem=
ents


   The dynamically changing topology, short connectivity, mobile
   transmitter and receivers, different antenna heights, and many-to-
   many communication types, make IEEE 802.11-OCB links significantly
   different from other IEEE 802.11 links.  Any IPv6 mechanism operating
   on IEEE 802.11-OCB link MUST support strong link asymetry, spatio-
   temporal link quality, fast address resolution and transmission.

   IEEE 802.11-OCB strongly differs from other 802.11 systems to operate
   outside of the context of a Basic Service Set.  This means in
   practice that IEEE 802.11-OCB does not rely on a Base Station for all
   Basic Service Set management.  In particular, IEEE 802.11-OCB SHALL
   NOT use beacons.  Any IPv6 mechanism requiring L2 services from IEEE
   802.11 beacons MUST support an alternative service.






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   Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
   implement a mechanism for transmitter and receiver to converge to a
   common channel.

   Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST
   implement an distributed mechanism to authenticate transmitters and
   receivers without the support of a DHCP server.

   Time synchronization not being available, IPv6 over IEEE 802.11-OCB
   MUST implement a higher layer mechanism for time synchronization
   between transmitters and receivers without the support of a NTP
   server.

   The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB
   MUST disable management mechanisms requesting acknowledgements or
   replies.

   The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE
   802.11-OCB MUST implement fast IPv6 mobility management mechanisms.


C.3.  Multiple interfaces<=
/h3>

   There are considerations for 2 or more IEEE 802.11-OCB interface
   cards per vehicle.  For each vehicle taking part in road traffic, one
   IEEE 802.11-OCB interface card could be fully allocated for Non IP
   safety-critical communication.  Any other IEEE 802.11-OCB may be used
   for other type of traffic.

   The mode of operation of these other wireless interfaces is not
   clearly defined yet.  One possibility is to consider each card as an
   independent network interface, with a specific MAC Address and a set
   of IPv6 addresses.  Another possibility is to consider the set of
   these wireless interfaces as a single network interface (not
   including the IEEE 802.11-OCB interface used by Non IP safety
   critical communications).  This will require specific logic to
   ensure, for example, that packets meant for a vehicle in front are
   actually sent by the radio in the front, or that multiple copies of
   the same packet received by multiple interfaces are treated as a
   single packet.  Treating each wireless interface as a separate
   network interface pushes such issues to the application layer.

   The privacy requirements of [] imply that if these multiple
   interfaces are represented by many network interface, a single
   renumbering event SHALL cause renumbering of all these interfaces.
   If one MAC changed and another stayed constant, external observers
   would be able to correlate old and new values, and the privacy
   benefits of randomization would be lost.




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   The privacy requirements of Non IP safety-critical communications
   imply that if a change of pseudonyme occurs, renumbering of all other
   interfaces SHALL also occur.


C.4.  MAC Address Generati=
on


   When designing the IPv6 over 802.11-OCB address mapping, we will
   assume that the MAC Addresses will change during well defined
   "renumbering events".  The 48 bits randomized MAC addresses wi=
ll have
   the following characteristics:

   o  Bit "Local/Global" set to "locally admninistered"=
.

   o  Bit "Unicast/Multicast" set to "Unicast".

   o  46 remaining bits set to a random value, using a random number
      generator that meets the requirements of [RFC4086].

   The way to meet the randomization requirements is to retain 46 bits
   from the output of a strong hash function, such as SHA256, taking as
   input a 256 bit local secret, the "nominal" MAC Address of the
   interface, and a representation of the date and time of the
   renumbering event.


Appendix D.  IEEE 802.11 Mess=
ages Transmitted in OCB mode


   For information, at the time of writing, this is the list of IEEE
   802.11 messages that may be transmitted in OCB mode, i.e. when
   dot11OCBActivated is true in a STA:

   o  The STA may send management frames of subtype Action and, if the
      STA maintains a TSF Timer, subtype Timing Advertisement;

   o  The STA may send control frames, except those of subtype PS-Poll,
      CF-End, and CF-End plus CFAck;

   o  The STA may send data frames of subtype Data, Null, QoS Data, and
      QoS Null.

Authors' Addresses








--_000_D5C8D56522C0C0sgundaveciscocom_--


From nobody Mon Aug 28 07:06:46 2017
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From: Russ Housley 
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Thanks very much.  These questions make me wonder whether there are =
different answers depending on motion.  If the vehicle is parked, a =
different set of solutions might be desirable.

Russ


> On Aug 27, 2017, at 11:00 PM, Sri Gundavelli (sgundave) =
 wrote:
>=20
>=20
> Attached is my review feedback.=20
>=20
> In general there is lot of good information in the document. But, =
there are also few areas where additional clarifications will greatly =
help.
>=20
> 1.) Its not clear, if the document makes any assumption on the =
operating environment/communication profile. There is not much =
discussion on that aspect; For example, Is it always a one-hop =
communication between RSU and OBU where the 802.11-OCB link?  So, is the =
use of IPv6 only in that context of 1-hop communication?=20
>=20
> 2.) There is also no discussion on how these links get formed in =
vehicular environment and when they are attached/detached.=20
>=20
> 3.) How do nodes discover each other?  How does ND resolution work? =
Are these messages received by a multiple RSU=E2=80=99s, or a single =
RSU? Whats the implication of that. Note that you don=E2=80=99t have =
that issue in 802.11, given the association to an access point, which in =
turn maps the links to a VLAN/subnet.
>=20
> 4.) What happens as a vehicle moves between RSU=E2=80=99s, how does it =
impact address configuration?   Is DHCPv6 based address configuration =
relevant here?
>=20
>=20
>  Please see inline for additional comments.
>=20
>=20
>=20
> ------------------------------------------------------------------
>=20
>  Transmission of IPv6 Packets over IEEE 802.11 Networks in mode =
Outside
>         the Context of a Basic Service Set (IPv6-over-80211ocb)
>               draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
>=20
>=20
> [Sri] May be change to, =E2=80=9C..in mode .." =E2=80=94> =
=E2=80=9C..operating in mode ..=E2=80=9D  ?
>=20
>=20
> Abstract
>=20
>    In order to transmit IPv6 packets on IEEE 802.11 networks run =
outside
>    the context of a basic service set (OCB, earlier "802.11p") there =
is
>    a need to define a few parameters such as the recommended Maximum
>    Transmission Unit size, the header format preceding the IPv6 =
header,
>    the Type value within it, and others.  This document describes =
these
>    parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
>    layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
>    Ethernet layers - by using an Ethernet Adaptation Layer.
>=20
> [Sri] Is it =E2=80=9Crecommended MTU size", or "supported MTU size on =
the 802.11 OCB link? =20
>=20
>=20
>    In addition, the document attempts to list what is different in
>    802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
>    layers, layers over which IPv6 protocols operates without issues.
>    Most notably, the operation outside the context of a BSS (OCB) has
>    impact on IPv6 handover behaviour and on IPv6 security.
>=20
> [Sri] Minor comment. May be instead of using the =E2=80=9Clayer=E2=80=9D=
 terminology, you may want to present this as IPv6 support on "802.11 =
OCB" links.=20
>=20
>    An example of an IPv6 packet captured while transmitted over an =
IEEE
>    802.11 OCB link (802.11p) is given.
>=20
> [Sri] Last paragraph can be ommitted in my view. That=E2=80=99s too =
much of detail for Abstract.
>=20
> Status of This Memo
>=20
>    This Internet-Draft is submitted in full conformance with the
>    provisions of BCP 78  and BCP 79 =
.
>=20
>    Internet-Drafts are working documents of the Internet Engineering
>    Task Force (IETF).  Note that other groups may also distribute
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018               [Page =
1]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    working documents as Internet-Drafts.  The list of current =
Internet-
>    Drafts is at http://datatracker.ietf.org/drafts/current/ =
.
>=20
>    Internet-Drafts are draft documents valid for a maximum of six =
months
>    and may be updated, replaced, or obsoleted by other documents at =
any
>    time.  It is inappropriate to use Internet-Drafts as reference
>    material or to cite them other than as "work in progress."
>=20
>    This Internet-Draft will expire on February 18, 2018.
>=20
> Copyright Notice
>=20
>    Copyright (c) 2017 IETF Trust and the persons identified as the
>    document authors.  All rights reserved.
>=20
>    This document is subject to BCP 78 =
 and the IETF Trust's Legal
>    Provisions Relating to IETF Documents
>    (http://trustee.ietf.org/license-info =
) in effect on the date of
>    publication of this document.  Please review these documents
>    carefully, as they describe your rights and restrictions with =
respect
>    to this document.  Code Components extracted from this document =
must
>    include Simplified BSD License text as described in Section 4.e of
>    the Trust Legal Provisions and are provided without warranty as
>    described in the Simplified BSD License.
>=20
> Table of Contents
>=20
>    1 =
.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   =
3 =

>    2 =
.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   =
5 =

>    3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    =
6
>    4 =
.  Aspects introduced by the OCB mode to 802.11  . . . . . . . .   =
6 =

>    5 =
.  Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . .  =
10 =

>      5.1 =
.  Maximum Transmission Unit (MTU) . . . . . . . . . . . . .  10 =

>      5.2 =
.  Frame Format  . . . . . . . . . . . . . . . . . . . . . .  11 =

>        5.2.1 =
.  Ethernet Adaptation Layer . . . . . . . . . . . . . .  12 =

>      5.3 =
.  Link-Local Addresses  . . . . . . . . . . . . . . . . . .  13 =

>      5.4 =
.  Address Mapping . . . . . . . . . . . . . . . . . . . . .  14 =

>        5.4.1 =
.  Address Mapping -- Unicast  . . . . . . . . . . . . .  14 =

>        5.4.2 =
.  Address Mapping -- Multicast  . . . . . . . . . . . .  14 =

>      5.5 =
.  Stateless Autoconfiguration . . . . . . . . . . . . . . .  15 =

>      5.6 =
.  Subnet Structure  . . . . . . . . . . . . . . . . . . . .  16 =

>    6 =
.  Example IPv6 Packet captured over a IEEE 802.11-OCB link  . .  =
16 =

>      6.1 =
.  Capture in Monitor Mode . . . . . . . . . . . . . . . . .  17 =

>      6.2 =
.  Capture in Normal Mode  . . . . . . . . . . . . . . . . .  19 =

>    7 =
.  Security Considerations . . . . . . . . . . . . . . . . . . .  =
21 =

>    8 =
.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  =
22 =

>    9 =
.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  =
22 =

>    10 =
. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  =
22 =

>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018               [Page =
2]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    11 =
. References  . . . . . . . . . . . . . . . . . . . . . . . . .  =
23 =

>      11.1 =
.  Normative References . . . . . . . . . . . . . . . . . .  23 =

>      11.2 =
.  Informative References . . . . . . . . . . . . . . . . .  24 =

>    Appendix A =
.  ChangeLog  . . . . . . . . . . . . . . . . . . . . .  26 =

>    Appendix B =
.  Changes Needed on a software driver 802.11a to
>                 become a                     802.11-OCB driver . . .  =
28 =

>    Appendix C =
.  Design Considerations  . . . . . . . . . . . . . . .  30 =

>      C.1 =
.  Vehicle ID  . . . . . . . . . . . . . . . . . . . . . . .  30 =

>      C.2 =
.  Reliability Requirements  . . . . . . . . . . . . . . . .  30 =

>      C.3 =
.  Multiple interfaces . . . . . . . . . . . . . . . . . . .  31 =

>      C.4 =
.  MAC Address Generation  . . . . . . . . . . . . . . . . .  32 =

>    Appendix D =
.  IEEE 802.11 Messages Transmitted in OCB mode . . . .  32 =

>    Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  =
32 =

>=20
> 1 =
.  Introduction
>=20
>    This document describes the transmission of IPv6 packets on IEEE =
Std
>    802.11 OCB networks (earlier known as 802.11p). =20
>=20
> [Sri] Please add a reference to the IEEE specification that defines =
the OCB mode.=20
>=20
>=20
> This involves the
>    layering of IPv6 networking on top of the IEEE 802.11 MAC layer =
(with
>    an LLC layer).  Compared to running IPv6 over the Ethernet MAC =
layer,
>    there is no modification required to the standards: IPv6 works fine
>    directly over 802.11 OCB too (with an LLC layer).
>=20
>    The term "802.11p" is an earlier definition.  As of year 2012, the
>    behaviour of "802.11p" networks has been rolled in the document =
IEEE
>    Std 802.11-2012.  In this document the term 802.11p disappears.
>    Instead, each 802.11p feature is conditioned by a flag in the
>    Management Information Base.  That flag is named "OCBActivated".
>    Whenever OCBActivated is set to true the feature it relates to
>    represents an earlier 802.11p feature.  For example, an 802.11
>    STAtion operating outside the context of a basic service set has =
the
>    OCBActivated flag set.  Such a station, when it has the flag set, =
it
>    uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.
>=20
>    In the following text we use the term "802.11p" to mean 802.11-2012
>    OCB.
>=20
>    The IPv6 network layer operates on 802.11 OCB in the same manner as
>    it operates on 802.11 WiFi, with a few particular exceptions.  The
>    IPv6 network layer operates on WiFi by involving an Ethernet
>    Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 =
headers
>    to Ethernet II headers.  The operation of IP on Ethernet is =
described
>    in [RFC1042 ] and [RFC2464 =
].  The situation of IPv6 =
networking layer
>    on Ethernet Adaptation Layer is illustrated below:
>=20
>=20
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018               [Page =
3]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>                  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                  |                 IPv6                  |
>                  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                  |       Ethernet Adaptation Layer       |
>                  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                  |             802.11 WiFi MAC           |
>                  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                  |             802.11 WiFi PHY           |
>                  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>=20
>    (in the above figure, a WiFi profile is represented; this is used
>    also for OCB profile.)
>=20
>    A more theoretical and detailed view of layer stacking, and
>    interfaces between the IP layer and 802.11 OCB layers, is =
illustrated
>    below.  The IP layer operates on top of the EtherType Protocol
>    Discrimination (EPD); this Discrimination layer is described in =
IEEE
>    Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP
>    (Link Layer Control Service Accesss Point).
>=20
>=20
>            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>            |                 IPv6                  |
>            +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+
>                        {   LLC_SAP  }                 802.11 OCB
>            +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+  Boundary
>            |            EPD          |       |     |
>            |                         | MLME  |     |
>            +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   |
>            |      MAC Sublayer       |       |     |  802.11 OCB
>            |     and ch. coord.      |       | SME |  Services
>            +-+-+-{   PHY_SAP  }+-+-+-+-+-+-+-|     |
>            |                         | PLME  |     |
>            |            PHY Layer    |   PLME_SAP  |
>            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>=20
>    In addition to the description of interface between IP and MAC =
using
>    "Ethernet Adaptation Layer" and "Ethernet Protocol Discrimination
>    (EPD)" it is worth mentioning that SNAP [RFC1042 =
] is used to carry
>    the IPv6 Ethertype.
>=20
>    However, there may be some deployment considerations helping =
optimize
>    the performances of running IPv6 over 802.11-OCB (e.g. in the case =
of
>    handovers between 802.11 OCB-enabled access routers, or the
>    consideration of using the IP security layer [RFC4301 =
]).
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018               [Page =
4]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    There are currently no specifications for handover between OCB =
links
>    since these are currently specified as LLC-1 links (i.e.
>    connectionless).  Any handovers must be performed above the Data =
Link
>    Layer.  Also, while there is no encryption applied below the =
network
>    layer using 802.11p, 1609.2 [ieee1609.2 =
] does provide security
>    services for applications to use so that there can easily be data
>    security over the air without invoking IPsec.
>=20
>    We briefly introduce the vehicular communication scenarios where =
IEEE
>    802.11-OCB links are used.=20
>=20
> [Sri] I have not seen much discussion on the link / communication =
assumptions.=20
>=20
>=20
>  This is followed by a description of
>    differences in specification terms, between 802.11 OCB and
>    802.11a/b/g/n (and the same differences expressed in terms of
>    requirements to software implementation are listed in Appendix B =
.)
>=20
>    The document then concentrates on the parameters of layering IP =
over
>    802.11 OCB as over Ethernet: value of MTU, the contents of Frame
>    Format, the rules for forming Interface Identifiers, the mechanism
>    for Address Mapping and for State-less Address Auto-configuration.
>    These are precisely the same as IPv6 over Ethernet [RFC2464 =
].
>=20
>    As an example, these characteristics of layering IPv6 straight over
>    LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 =
packet
>    captured over a 802.11 OCB link; this is described in the section
>    Section 6 =
.
>=20
>    A couple of points can be considered as different, although they =
are
>    not required in order to have a working implementation of =
IPv6-over-
>    802.11-OCB.  These points are consequences of the OCB operation =
which
>    is particular to 802.11 OCB (Outside the Context of a BSS).  First,
>    the handovers between OCB links need specific behaviour for IP =
Router
>    Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of
>    higher layer messages such as the 'Basic Safety Message' (in the =
US)
>    or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE
>    Routing Advertisement'; second, the IP security mechanisms are
>    necessary, since OCB means that 802.11 is stripped of all 802.11
>    link-layer security; a small additional security aspect which is
>    shared between 802.11 OCB and other 802.11 links is the privacy
>    concerns related to the address formation mechanisms.
>=20
>    In the published literature, many documents describe aspects =
related
>    to running IPv6 over 802.11 OCB:
>    [I-D.jeong-ipwave-vehicular-networking-survey =
].
>=20
> 2 =
.  Terminology
>=20
>    The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
>    "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in =
this
>    document are to be interpreted as described in RFC 2119 =
 [RFC2119 =
].
>=20
>=20
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> Petrescu, et al.        Expires February 18, 2018               [Page =
5]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    RSU: Road Side Unit.  A computer equipped with at least one IEEE
>    802.11 interface operated in OCB mode.  This definition applies to
>    this document.  An RSU may be connected to the Internet, and may be
>    equipped with additional wired or wireless network interfaces =
running
>    IP.  An RSU MAY be an IP Router.
>=20
>=20
> [Sri] RSU can be compared to an 802.11 access point; Or, WTP as =
defined in CAPWAP specification, RFC5415.
>=20
> Perhaps. rephrase as below?:
>=20
> "RSU: Road Side Unit. Its a wireless termination point (WTP), as =
defined in RFC5415 with one key difference, where the wireless physical =
and the mac layer is configured to operate in 802.11 OCB mode.  The RSU =
communicates with the On board Unit (OBU) in the vehicle over 802.11 =
wireless link operating in OCB mode.=E2=80=9D=20
>=20
>=20
> ** Also, since you are defining the RSU term, should you also not =
define OBU (On board Unit) in the vehicle which is the entity on the =
other end of the link? =E2=80=9CRSU ----802.11-OCB=E2=80=94=E2=80=94OBU=E2=
=80=9D ? May be introduce the OCB definition separately, just as you did =
with RSU, and show the communication link as 802.11-OCB.
>=20
>=20
>    OCB: outside the context of a basic service set (BSS): A mode of
>    operation in which a STA is not a member of a BSS and does not
>    utilize IEEE Std 802.11 authentication, association, or data
>    confidentiality.
>=20
>    802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that =
is
>    flagged by "dot11OCBActivated".  This means: IEEE 802.11e for =
quality
>    of service; 802.11j-2004 for half-clocked operations; and (what was
>    known earlier as) 802.11p for operation in the 5.9 GHz band and in
>    mode OCB.
>=20
>=20
> [Sri] The text starting with. =E2=80=9CThis means=E2=80=9D is not =
clear to me. Does it 802.11e is supported with 802.11OCB mode. Please =
clarify
>=20
>=20
> 3 =
.  Communication Scenarios where IEEE 802.11 OCB Links are Used
>=20
>    The IEEE 802.11 OCB Networks are used for vehicular communications,
>    as 'Wireless Access in Vehicular Environments'.  The IP =
communication
>    scenarios for these environments have been described in several
>    documents, among which we refer the reader to one recently updated
>    [I-D.petrescu-its-scenarios-reqs =
], about scenarios and requirements
>    for IP in Intelligent Transportation Systems.
>=20
>=20
> [Sri] You can do bit more justice to this section.=20
> Explain the link model.  =E2=80=9CSTA ----802.11-OCB=E2=80=94=E2=80=94ST=
A=E2=80=9D. Then talk about the applicability in Vehicular networks, =
with STA's as RSU and OCB.
> You may also want to talk about, how links get formed/terminated; how =
nodes peer/discover and how mobility works ..etc.  While 802.11-OCB is =
clearly specified and the use of IPv6 over such link is also not =
radically new, but the operating environment which is vehicular brings =
many new things. That description is not present any where.
>=20
> 4 =
.  Aspects introduced by the OCB mode to 802.11
>=20
>    In the IEEE 802.11 OCB mode, all nodes in the wireless range can
>    directly communicate with each other without authentication/
>    association procedures.  Briefly, the IEEE 802.11 OCB mode has the
>    following properties:
>=20
>=20
> [Sri] Can you add some text on how nodes (ST1 and STA2) discover each =
other on such links supporting 802.11 OCB mode.
>    o  The use by each node of a 'wildcard' BSSID (i.e., each bit of =
the
>       BSSID is set to 1)
>=20
>    o  No IEEE 802.11 Beacon frames transmitted
>=20
>    o  No authentication required
>=20
>    o  No association needed
>=20
>    o  No encryption provided
>=20
> [Sri] Can you clarify what you mean when you say =E2=80=9CNo xxx =
required=E2=80=9D / =E2=80=9CNo xxx needed=E2=80=9D  for the above =
capabilities.  What does =E2=80=9Cneeded=E2=80=9D or =E2=80=9Crequired=E2=80=
=9D mean?  Does it mean, =E2=80=9CAuthentication", =E2=80=9CAssociation" =
and =E2=80=9CEncryption=E2=80=9D is optional on this link, or that its =
not supported on 802.11 OCB links. =20
>=20
>    o  Flag dot11OCBActivated set to true
>=20
>    The following message exchange diagram illustrates a comparison
>    between traditional 802.11 and 802.11 in OCB mode.  The 'Data'
>=20
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> Petrescu, et al.        Expires February 18, 2018               [Page =
6]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    messages can be IP messages such as the messages used in Stateless =
or
>    Stateful Address Auto-Configuration, or other IP messages. =20
>=20
>=20
> [Sri] Lets separate the discussion on IP Address configuration using =
SLAAC/DHCP on such links from the above description. The Data packets =
here can be application packets such as HTTP or other packets. May be =
additional discussion is needed on the IP address configuration on =
802.11-OCB links.=20
>=20
>=20
> Other
>    802.11 management and control frames (non IP) may be transmitted, =
as
>    specified in the 802.11 standard.  For information, the names of
>    these messages as currently specified by the 802.11 standard are
>    listed in Appendix D =
.
>=20
>=20
>=20
>=20
>=20
>=20
>      STA                    AP              STA1                   =
STA2
>      |                      |               |                      |
>      |<------ Beacon -------|               |<------ Data -------->|
>      |                      |               |                      |
>      |---- Probe Req. ----->|               |<------ Data -------->|
>      |<--- Probe Res. ------|               |                      |
>      |                      |               |<------ Data -------->|
>      |---- Auth Req. ------>|               |                      |
>      |<--- Auth Res. -------|               |<------ Data -------->|
>      |                      |               |                      |
>      |---- Asso Req. ------>|               |<------ Data -------->|
>      |<--- Asso Res. -------|               |                      |
>      |                      |               |<------ Data -------->|
>      |<------ Data -------->|               |                      |
>      |<------ Data -------->|               |<------ Data -------->|
>=20
>     (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode
>=20
>=20
>    The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010
>    [ieee802.11p-2010 =
] as an amendment to IEEE Std 802.11 (TM) -2007,
>    titled "Amendment 6: Wireless Access in Vehicular Environments".
>    Since then, this amendment has been included in IEEE =
802.11(TM)-2012
>    [ieee802.11-2012 =
], titled "IEEE Standard for Information technology--
>    Telecommunications and information exchange between systems Local =
and
>    metropolitan area networks--Specific requirements Part 11: Wireless
>    LAN Medium Access Control (MAC) and Physical Layer (PHY)
>    Specifications"; the modifications are diffused throughout various
>    sections (e.g. the Time Advertisement message described in the
>    earlier 802.11 (TM) p amendment is now described in section 'Frame
>    formats', and the operation outside the context of a BSS described =
in
>    section 'MLME').
>=20
>    In document 802.11-2012, specifically anything referring
>    "OCBActivated", or "outside the context of a basic service set" is
>    actually referring to the 802.11p aspects introduced to 802.11.  =
Note
>    that in earlier 802.11p documents the term "OCBEnabled" was used
>    instead of te current "OCBActivated".
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018               [Page =
7]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    In order to delineate the aspects introduced by 802.11 OCB to =
802.11,
>    we refer to the earlier [ieee802.11p-2010 =
].  The amendment is
>    concerned with vehicular communications, where the wireless link is
>    similar to that of Wireless LAN (using a PHY layer specified by
>    802.11a/b/g/n), but which needs to cope with the high mobility =
factor
>    inherent in scenarios of communications between moving vehicles, =
and
>    between vehicles and fixed infrastructure deployed along roads.
>    While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is
>    concerned more with MAC modifications, and a little with PHY
>    modifications; the others are mainly about PHY modifications.  It =
is
>    possible in practice to combine a 'p' MAC with an 'a' PHY by
>    operating outside the context of a BSS with OFDM at 5.4GHz.
>=20
>    The 802.11 OCB links are specified to be compatible as much as
>    possible with the behaviour of 802.11a/b/g/n and future generation
>    IEEE WLAN links.  =46rom the IP perspective, an 802.11 OCB MAC =
layer
>    offers practically the same interface to IP as the WiFi and =
Ethernet
>    layers do (802.11a/b/g/n and 802.3).
>=20
>=20
> [Sri] A packet sent from a vehicle=E2=80=99s OBU is received by a =
single RSU, or multiple RSU=E2=80=99s? How does the link-layer =
resolution happen?
>=20
>    To support this similarity statement (IPv6 is layered on top of LLC
>    on top of 802.11 OCB similarly as on top of LLC on top of
>    802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful =
to
>    analyze the differences between 802.11 OCB and 802.11 =
specifications.
>    Whereas the 802.11p amendment specifies relatively complex and
>    numerous changes to the MAC layer (and very little to the PHY =
layer),
>    we note there are only a few characteristics which may be important
>    for an implementation transmitting IPv6 packets on 802.11 OCB =
links.
>=20
>    In the list below, the only 802.11 OCB fundamental points which
>    influence IPv6 are the OCB operation and the 12Mbit/s maximum which
>    may be afforded by the IPv6 applications.
>=20
>=20
> [Sri] I am really not sure how link throughput (12Mbps) relates to =
"IPv6 support on OCB links". =20
>=20
>=20
>    o  Operation Outside the Context of a BSS (OCB): the (earlier
>       802.11p) 802.11-OCB links are operated without a Basic Service =
Set
>       (BSS).  This means that the frames IEEE 802.11 Beacon, =
Association
>       Request/Response, Authentication Request/Response, and similar,
>       are not used.  The used identifier of BSS (BSSID) has a
>       hexadecimal value always 0xffffffffffff (48 '1' bits, =
represented
>       as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'
>       BSSID), as opposed to an arbitrary BSSID value set by
>       administrator (e.g.  'My-Home-AccessPoint').  The OCB operation =
-
>       namely the lack of beacon-based scanning and lack of
>       authentication - has a potentially strong impact on the use of =
the
>       Mobile IPv6 protocol [RFC6275 =
] and on the protocols for IP layer
>       security [RFC4301 ].
>=20
>=20
> [Sri] The document till now has been arguing heavily on how IPv6 =
operates so naturally on these links and now I see discussion on =
=E2=80=9CImpact to a high-level protocol such as MIPv6=E2=80=9D. You may =
want to fix the earlier text. In any case,  the absence of link-layer =
security practically impacts every application, not just MIPv6.  Also, =
MIPv6 does not make any assumptions on the link-layer security.  Also, =
the the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes the messages readable by =
all other RSU=E2=80=99s in proximity. I think the discussion on the =
nature of the link, who all see=E2=80=99s the messages.. how L2 =
addresses are resolved is not explained clearly.=20
>=20
>=20
>=20
>    o  Timing Advertisement: is a new message defined in 802.11-OCB,
>       which does not exist in 802.11a/b/g/n.  This message is used by
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018               [Page =
8]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>       stations to inform other stations about the value of time.  It =
is
>       similar to the time as delivered by a GNSS system (Galileo, GPS,
>       ...) or by a cellular system.  This message is optional for
>       implementation.  At the date of writing, an experienced reviewer
>       considers that currently no field testing has used this message.
>       Another implementor considers this feature implemented in an
>       initial manner.  In the future, it is speculated that this =
message
>       may be useful for very simple devices which may not have their =
own
>       hardware source of time (Galileo, GPS, cellular network), or by
>       vehicular devices situated in areas not covered by such network
>       (in tunnels, underground, outdoors but shaded by foliage or
>       buildings, in remote areas, etc.)
>=20
>=20
> [Sri] The first part explaining Timing Advertisement messages is =
great, but the rest of the commentary is unnecessary and not needed. We =
don=E2=80=99t speculate the protocol adoption success in IETF =
specifications, or about the experience level of the =E2=80=9Creviewer" =
:)
>=20
>=20
>    o  Frequency range: this is a characteristic of the PHY layer, with
>       almost no impact to the interface between MAC and IP.  However, =
it
>       is worth considering that the frequency range is regulated by a
>       regional authority (ARCEP, ETSI, FCC, etc.); as part of the
>       regulation process, specific applications are associated with
>       specific frequency ranges.  In the case of 802.11-OCB, the
>       regulator associates a set of frequency ranges, or slots within =
a
>       band, to the use of applications of vehicular communications, in =
a
>       band known as "5.9GHz".  This band is "5.9GHz" which is =
different
>       from the bands "2.4GHz" or "5GHz" used by Wireless LAN.  =
However,
>       as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz"
>       bands is exempt from owning a license in EU (in US the 5.9GHz is =
a
>       licensed band of spectrum; for the the fixed infrastructure an
>       explicit FCC autorization is required; for an onboard device a
>       'licensed-by-rule' concept applies: rule certification =
conformity
>       is required); however technical conditions are different than
>       those of the bands "2.4GHz" or "5GHz".  On one hand, the allowed
>       power levels, and implicitly the maximum allowed distance =
between
>       vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20
>       dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum
>       distance of approximately 1km, compared to approximately 50m.  =
On
>       the other hand, specific conditions related to congestion
>       avoidance, jamming avoidance, and radar detection are imposed on
>       the use of DSRC (in US) and on the use of frequencies for
>       Intelligent Transportation Systems (in EU), compared to Wireless
>       LAN (802.11a/b/g/n).
>=20
>    o  Prohibition of IPv6 on some channels relevant for IEEE =
802.11-OCB,
>       as opposed to IPv6 not being prohibited on any channel on which
>       802.11a/b/g/n runs:
>=20
>       *  Some channels are reserved for safety communications; the =
IPv6
>          packets should not be sent on these channels.
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018               [Page =
9]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>       *  At the time of writing, the prohibition is explicit at higher
>          layer protocols providing services to the application; these
>          higher layer protocols are specified in IEEE 1609 documents.
>=20
>       *  National or regional specifications and regulations specify =
the
>          use of different channels; these regulations must be =
followed.
>=20
>    o  'Half-rate' encoding: as the frequency range, this parameter is
>       related to PHY, and thus has not much impact on the interface
>       between the IP layer and the MAC layer.
>=20
>    o  In vehicular communications using 802.11-OCB links, there are
>       strong privacy requirements with respect to addressing.  While =
the
>       802.11-OCB standard does not specify anything in particular with
>       respect to MAC addresses, in these settings there exists a =
strong
>       need for dynamic change of these addresses (as opposed to the =
non-
>       vehicular settings - real wall protection - where fixed MAC
>       addresses do not currently pose some privacy risks).  This is
>       further described in section Section 7 =
.  A relevant function is
>       described in IEEE 1609.3-2016 [ieee1609.3 =
], clause 5.5.1 and IEEE
>       1609.4-2016 [ieee1609.4 =
], clause 6.7.
>=20
>    Other aspects particular to 802.11-OCB which are also particular to
>    802.11 (e.g. the 'hidden node' operation) may have an influence on
>    the use of transmission of IPv6 packets on 802.11-OCB networks.  =
The
>    subnet structure which may be assumed in 802.11-OCB networks is
>    strongly influenced by the mobility of vehicles.
>=20
>=20
> [Sri] Per my earlier comment, the link model, addressing ..etc needs =
to be explained in more detail. It is not clear what exactly the =
=E2=80=9Csubnet structure=E2=80=9D that is assumed in 802.11-OCB.
>=20
> 5 =
.  Layering of IPv6 over 802.11-OCB as over Ethernet
>=20
> 5.1 =
.  Maximum Transmission Unit (MTU)
>=20
>    The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is
>    the same value as IPv6 packets on Ethernet links, as specified in
>    [RFC2464 ].  This value of the =
MTU respects the recommendation that
>    every link in the Internet must have a minimum MTU of 1280 octets
>    (stated in [RFC2460 ], and the =
recommendations therein, especially
>    with respect to fragmentation).  If IPv6 packets of size larger =
than
>    1500 bytes are sent on an 802.11-OCB interface card then the IP =
stack
>    will fragment.  In case there are IP fragments, the field "Sequence
>    number" of the 802.11 Data header containing the IP fragment field =
is
>    increased.
>=20
>    Non-IP packets such as WAVE Short Message Protocol (WSMP) can be
>    delivered on 802.11-OCB links.  Specifications of these packets are
>    out of scope of this document, and do not impose any limit on the =
MTU
>    size, allowing an arbitrary number of 'containers'.  Non-IP packets
>    such as ETSI 'geonet' packets have an MTU of 1492 bytes.
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
10]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    The Equivalent Transmit Time on Channel is a concept that may be =
used
>    as an alternative to the MTU concept.  A rate of transmission may =
be
>    specified as well.  The ETTC, rate and MTU may be in direct
>    relationship.
>=20
> [Sri] The last paragraph needs some additional context. Did 802.11-OCB =
introduce ETTC concept? =20
>=20
>=20
>=20
> 5.2 =
.  Frame Format
>=20
>    IP packets are transmitted over 802.11-OCB as standard Ethernet
>    packets.  As with all 802.11 frames, an Ethernet adaptation layer =
is
>    used with 802.11-OCB as well.  This Ethernet Adaptation Layer
>    performing 802.11-to-Ethernet is described in Section 5.2.1 =
.  The
>    Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal =
86DD,
>    or otherwise #86DD).
>=20
>    The Frame format for transmitting IPv6 on 802.11-OCB networks is =
the
>    same as transmitting IPv6 on Ethernet networks, and is described in
>    section=C2=A03 of [RFC2464] =
.  The frame format for =
transmitting IPv6
>    packets over Ethernet is illustrated below:
>=20
>=20
>                     0                   1
>                     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
>                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                     |          Destination          |
>                     +-                             -+
>                     |            Ethernet           |
>                     +-                             -+
>                     |            Address            |
>                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                     |             Source            |
>                     +-                             -+
>                     |            Ethernet           |
>                     +-                             -+
>                     |            Address            |
>                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                     |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
>                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                     |             IPv6              |
>                     +-                             -+
>                     |            header             |
>                     +-                             -+
>                     |             and               |
>                     +-                             -+
>                     /            payload ...        /
>                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                     (Each tic mark represents one bit.)
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
11]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    Ethernet II Fields:
>=20
>    Destination Ethernet Address
>       the MAC destination address.
>=20
>    Source Ethernet Address
>       the MAC source address.
>=20
>    1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
>       binary representation of the EtherType value 0x86DD.
>=20
>    IPv6 header and payload
>       the IPv6 packet containing IPv6 header and payload.
>=20
> 5.2.1 =
.  Ethernet Adaptation Layer
>=20
>    In general, an 'adaptation' layer is inserted between a MAC layer =
and
>    the Networking layer.  This is used to transform some parameters
>    between their form expected by the IP stack and the form provided =
by
>    the MAC layer.  For example, an 802.15.4 adaptation layer may =
perform
>    fragmentation and reassembly operations on a MAC whose maximum =
Packet
>    Data Unit size is smaller than the minimum MTU recognized by the =
IPv6
>    Networking layer.  Other examples involve link-layer address
>    transformation, packet header insertion/removal, and so on.
>=20
>    An Ethernet Adaptation Layer makes an 802.11 MAC look to IP
>    Networking layer as a more traditional Ethernet layer.  At =
reception,
>    this layer takes as input the IEEE 802.11 Data Header and the
>    Logical-Link Layer Control Header and produces an Ethernet II =
Header.
>    At sending, the reverse operation is performed.
>=20
>=20
>  =
+--------------------+------------+-------------+---------+-----------+
>  | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 =
Trailer|
>  =
+--------------------+------------+-------------+---------+-----------+
>   \                               /                         \         =
/
>     -----------------------------                             --------
>                    ^---------------------------------------------/
>                    |
>            802.11-to-Ethernet Adaptation Layer
>                    |
>                    v
>  +---------------------+-------------+---------+
>  | Ethernet II Header  | IPv6 Header | Payload |
>  +---------------------+-------------+---------+
>=20
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
12]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    The Receiver and Transmitter Address fields in the 802.11 Data =
Header
>    contain the same values as the Destination and the Source Address
>    fields in the Ethernet II Header, respectively.  The value of the
>    Type field in the LLC Header is the same as the value of the Type
>    field in the Ethernet II Header.
>=20
>    The ".11 Trailer" contains solely a 4-byte Frame Check Sequence.
>=20
>    The Ethernet Adaptation Layer performs operations in relation to IP
>    fragmentation and MTU.  One of these operations is briefly =
described
>    in section Section 5.1 =
.
>=20
>    In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11
>    Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in
>    the following figure:
>=20
>=20
> =
+--------------------+-------------+-------------+---------+-----------+
> | 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 =
Trailer|
> =
+--------------------+-------------+-------------+---------+-----------+
>=20
> or
>=20
> =
+--------------------+-------------+-------------+---------+-----------+
> | 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 =
Trailer|
> =
+--------------------+-------------+-------------+---------+-----------+
>=20
>=20
>    The distinction between the two formats is given by the value of =
the
>    field "Type/Subtype".  The value of the field "Type/Subtype" in the
>    802.11 Data header is 0x0020.  The value of the field =
"Type/Subtype"
>    in the 802.11 QoS header is 0x0028.
>=20
>    The mapping between qos-related fields in the IPv6 header (e.g.
>    "Traffic Class", "Flow label") and fields in the "802.11 QoS Data
>    Header" (e.g.  "QoS Control") are not specified in this document.
>    Guidance for a potential mapping is provided in
>    [I-D.ietf-tsvwg-ieee-802-11 =
], although it is not specific to OCB
>    mode.
>=20
>=20
>=20
> [Sri] The applicability of the QoS mapping draft to 802.11-OCB needs =
further investigation, IMO.
>=20
>=20
>=20
> 5.3 =
.  Link-Local Addresses
>=20
>    The link-local address of an 802.11-OCB interface is formed in the
>    same manner as on an Ethernet interface.  This manner is described =
in
>    section=C2=A05 of [RFC2464] =
.
>=20
>=20
>=20
> [Sri] Does this go against the 8064 recommendation on Interface =
identifier generation?
> May be RFC7217 for interface identifier generation in conjunction with =
the link-local address generation per RFC2464
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
13]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
> 5.4 =
.  Address Mapping
>=20
>    For unicast as for multicast, there is no change from the unicast =
and
>    multicast address mapping format of Ethernet interfaces, as defined
>    by sections 6 =
 and 7 =
 of [RFC2464 ].
>=20
>=20
>=20
> [Sri] RFC6085 specified mapping is also relevant; If the communication =
peers are aware that there is only one peer, it should apply 6085 =
specified mapping. That mode is relevant for 802.11-OCB types links as =
well.
>=20
>=20
> 5.4.1 =
.  Address Mapping -- Unicast
>=20
>    The procedure for mapping IPv6 unicast addresses into Ethernet =
link-
>    layer addresses is described in [RFC4861 =
].  The Source/Target Link-
>    layer Address option has the following form when the link-layer is
>    Ethernet.
>=20
> [Sri] I thought, mapping of IPv6 unicast addresses to Ethernet =
link-layer addresses is specified in section 6, of RFC2464 and not in =
RFC4861.
>=20
>=20
>=20
>                       0                   1
>                       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
>                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                      |     Type      |    Length     |
>                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                      |                               |
>                      +-          Ethernet           -+
>                      |                               |
>                      +-           Address           -+
>                      |                               |
>                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>=20
>    Option fields:
>=20
>    Type
>       1 for Source Link-layer address.
>       2 for Target Link-layer address.
>=20
>    Length
>       1 (in units of 8 octets).
>=20
>    Ethernet Address
>       The 48 bit Ethernet IEEE 802 address, in canonical bit order.
>=20
> 5.4.2 =
.  Address Mapping -- Multicast
>=20
>    IPv6 protocols often make use of IPv6 multicast addresses in the
>    destination field of IPv6 headers.  For example, an ICMPv6 link-
>    scoped Neighbor Advertisement is sent to the IPv6 address ff02::1
>    denoted "all-nodes" address.  When transmitting these packets on
>    802.11-OCB links it is necessary to map the IPv6 address to a MAC
>    address.
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
14]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    The same mapping requirement applies to the link-scoped multicast
>    addresses of other IPv6 protocols as well.  In DHCPv6, the
>    "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF =
the
>    "All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped
>    on a multicast MAC address.
>=20
>    An IPv6 packet with a multicast destination address DST, consisting
>    of the sixteen octets DST[1] through DST[16], is transmitted to the
>    IEEE 802.11-OCB MAC multicast address whose first two octets are =
the
>    value 0x3333 and whose last four octets are the last four octets of
>    DST.
>=20
> [Sri] Please add a reference to Section 7, RFC4861 and also RFC6085. =
In general, for both unicast and multicast, you may want to clearly say =
that this is per the existing specs and duplicated here for convenience.=20=

>=20
>                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                      |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
>                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                      |   DST[13]     |   DST[14]     |
>                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>                      |   DST[15]     |   DST[16]     |
>                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>=20
>    A Group ID TBD of length 112bits may be requested from IANA; this
>    Group ID signifies "All 80211OCB Interfaces Address".  Only the =
least
>    32 significant bits of this "All 80211OCB Interfaces Address" will =
be
>    mapped to and from a MAC multicast address.
>=20
>    Transmitting IPv6 packets to multicast destinations over 802.11 =
links
>    proved to have some performance issues
>    [I-D.perkins-intarea-multicast-ieee802 =
].  These issues may be
>    exacerbated in OCB mode.  Solutions for these problems should
>    consider the OCB mode of operation.
>=20
> 5.5 =
.  Stateless Autoconfiguration
>=20
>    The Interface Identifier for an 802.11-OCB interface is formed =
using
>    the same rules as the Interface Identifier for an Ethernet =
interface;
>    this is described in section=C2=A04 of [RFC2464] =
.  No changes are needed,
>    but some care must be taken when considering the use of the SLAAC
>    procedure.
>=20
>=20
> [Sri] Per my earlier comment, please refer to the current =
recommendation on interface-identifier generation and its use in =
link-local, global or other addresses.
>=20
>=20
>    The bits in the the interface identifier have no generic meaning =
and
>    the identifier should be treated as an opaque value.  The bits
>    'Universal' and 'Group' in the identifier of an 802.11-OCB =
interface
>    are significant, as this is an IEEE link-layer address.  The =
details
>    of this significance are described in [I-D.ietf-6man-ug =
].
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
15]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    As with all Ethernet and 802.11 interface identifiers ([RFC7721 =
]),
>    the identifier of an 802.11-OCB interface may involve privacy =
risks.
>    A vehicle embarking an On-Board Unit whose egress interface is
>    802.11-OCB may expose itself to eavesdropping and subsequent
>    correlation of data; this may reveal data considered private by the
>    vehicle owner; there is a risk of being tracked; see the privacy
>    considerations described in Appendix C =
.
>=20
>=20
> [Sri] I think there are other security issues here; the absence of =
link-layer security opens up Mac-spoofing and IP address hijacking.  =
That should be mentioned.
>=20
>=20
>    If stable Interface Identifiers are needed in order to form IPv6
>    addresses on 802.11-OCB links, it is recommended to follow the
>    recommendation in [I-D.ietf-6man-default-iids =
].
>=20
> 5.6 =
.  Subnet Structure
>=20
>    The 802.11 networks in OCB mode may be considered as 'ad-hoc'
>    networks.  The addressing model for such networks is described in
>    [RFC5889 ].
>=20
>=20
> [Sri] Per my earlier comment, there is no system level view of the =
network where 802.11-OCB links are used. So, in the absence of such =
discussion So, I am not sure what part of RFC5889 is applicable here. =
For example, link-local addresses may just work fine.=20
>=20
>=20
> 6 =
.  Example IPv6 Packet captured over a IEEE 802.11-OCB link
>=20
>    We remind that a main goal of this document is to make the case =
that
>    IPv6 works fine over 802.11-OCB networks.  Consequently, this =
section
>    is an illustration of this concept and thus can help the =
implementer
>    when it comes to running IPv6 over IEEE 802.11-OCB.  By way of
>    example we show that there is no modification in the headers when
>    transmitted over 802.11-OCB networks - they are transmitted like =
any
>    other 802.11 and Ethernet packets.
>=20
>    We describe an experiment of capturing an IPv6 packet on an
>    802.11-OCB link.  In this experiment, the packet is an IPv6 Router
>    Advertisement.  This packet is emitted by a Router on its =
802.11-OCB
>    interface.  The packet is captured on the Host, using a network
>    protocol analyzer (e.g.  Wireshark); the capture is performed in =
two
>    different modes: direct mode and 'monitor' mode.  The topology used
>    during the capture is depicted below.
>=20
>=20
>               +--------+                                +-------+
>               |        |        802.11-OCB Link         |       |
>            ---| Router |--------------------------------| Host  |
>               |        |                                |       |
>               +--------+                                +-------+
>=20
>=20
>    During several capture operations running from a few moments to
>    several hours, no message relevant to the BSSID contexts were
>    captured (no Association Request/Response, Authentication Req/Resp,
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
16]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    Beacon).  This shows that the operation of 802.11-OCB is outside =
the
>    context of a BSSID.
>=20
>    Overall, the captured message is identical with a capture of an =
IPv6
>    packet emitted on a 802.11b interface.  The contents are precisely
>    similar.
>=20
>=20
> [Sri] I suggest moving this discussion under the section =
=E2=80=9CImplementation Status=E2=80=9D, which will eventually be =
removed from the RFC. There is nothing new here. This are details on =
experimentation. But, if you think there is some useful information  =
such as discussion on Capture mode ..etc, you may want to move this =
entire section to Appendix. Implementors may use these tools for =
verification.
>=20
>=20
>=20
> 6.1 =
.  Capture in Monitor Mode
>=20
>    The IPv6 RA packet captured in monitor mode is illustrated below.
>    The radio tap header provides more flexibility for reporting the
>    characteristics of frames.  The Radiotap Header is prepended by =
this
>    particular stack and operating system on the Host machine to the RA
>    packet received from the network (the Radiotap Header is not =
present
>    on the air).  The implementation-dependent Radiotap Header is =
useful
>    for piggybacking PHY information from the chip's registers as data =
in
>    a packet understandable by userland applications using Socket
>    interfaces (the PHY interface can be, for example: power levels, =
data
>    rate, ratio of signal to noise).
>=20
>    The packet present on the air is formed by IEEE 802.11 Data Header,
>    Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.
>=20
>=20
>=20
>      Radiotap Header v0
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |Header Revision|  Header Pad   |    Header length              |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                         Present flags                         |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      | Data Rate     |             Pad                               |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>      IEEE 802.11 Data Header
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |  Type/Subtype and Frame Ctrl  |          Duration             |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                      Receiver Address...
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      ... Receiver Address           |      Transmitter Address...
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      ... Transmitter Address                                        |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                            BSS Id...
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      ... BSS Id                     |  Frag Number and Seq Number   |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
17]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>      Logical-Link Control Header
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |      DSAP   |I|     SSAP    |C| Control field | Org. code...
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      ... Organizational Code        |             Type              |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>      IPv6 Base Header
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |Version| Traffic Class |           Flow Label                  |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |         Payload Length        |  Next Header  |   Hop Limit   |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                                                               |
>      +                                                               +
>      |                                                               |
>      +                         Source Address                        +
>      |                                                               |
>      +                                                               +
>      |                                                               |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                                                               |
>      +                                                               +
>      |                                                               |
>      +                      Destination Address                      +
>      |                                                               |
>      +                                                               +
>      |                                                               |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>      Router Advertisement
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |     Type      |     Code      |          Checksum             |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                         Reachable Time                        |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                          Retrans Timer                        |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |   Options ...
>      +-+-+-+-+-+-+-+-+-+-+-+-
>=20
>=20
>    The value of the Data Rate field in the Radiotap header is set to 6
>    Mb/s.  This indicates the rate at which this RA was received.
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
18]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    The value of the Transmitter address in the IEEE 802.11 Data Header
>    is set to a 48bit value.  The value of the destination address is
>    33:33:00:00:00:1 (all-nodes multicast address).  The value of the =
BSS
>    Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network
>    protocol analyzer as being "broadcast".  The Fragment number and
>    sequence number fields are together set to 0x90C6.
>=20
>    The value of the Organization Code field in the Logical-Link =
Control
>    Header is set to 0x0, recognized as "Encapsulated Ethernet".  The
>    value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise
>    #86DD), recognized as "IPv6".
>=20
>    A Router Advertisement is periodically sent by the router to
>    multicast group address ff02::1.  It is an icmp packet type 134.  =
The
>    IPv6 Neighbor Discovery's Router Advertisement message contains an
>    8-bit field reserved for single-bit flags, as described in [RFC4861 =
].
>=20
>    The IPv6 header contains the link local address of the router
>    (source) configured via EUI-64 algorithm, and destination address =
set
>    to ff02::1.  Recent versions of network protocol analyzers (e.g.
>    Wireshark) provide additional informations for an IP address, if a
>    geolocalization database is present.  In this example, the
>    geolocalization database is absent, and the "GeoIP" information is
>    set to unknown for both source and destination addresses (although
>    the IPv6 source and destination addresses are set to useful =
values).
>    This "GeoIP" can be a useful information to look up the city,
>    country, AS number, and other information for an IP address.
>=20
> [Sri] Not sure, why all of this text should be in the specification.=20=

>=20
>    The Ethernet Type field in the logical-link control header is set =
to
>    0x86dd which indicates that the frame transports an IPv6 packet.  =
In
>    the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
>    which is he corresponding multicast MAC address.  The BSS id is a
>    broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link
>    duration between vehicles and the roadside infrastructure, there is
>    no need in IEEE 802.11-OCB to wait for the completion of =
association
>    and authentication procedures before exchanging data.  IEEE
>    802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)
>    and may start communicating as soon as they arrive on the
>    communication channel.
>=20
> 6.2 =
.  Capture in Normal Mode
>=20
>    The same IPv6 Router Advertisement packet described above (monitor
>    mode) is captured on the Host, in the Normal mode, and depicted
>    below.
>=20
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
19]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>      Ethernet II Header
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                       Destination...
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      ...Destination                 |           Source...
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      ...Source                                                      |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |          Type                 |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>      IPv6 Base Header
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |Version| Traffic Class |           Flow Label                  |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |         Payload Length        |  Next Header  |   Hop Limit   |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                                                               |
>      +                                                               +
>      |                                                               |
>      +                         Source Address                        +
>      |                                                               |
>      +                                                               +
>      |                                                               |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                                                               |
>      +                                                               +
>      |                                                               |
>      +                      Destination Address                      +
>      |                                                               |
>      +                                                               +
>      |                                                               |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>=20
>      Router Advertisement
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |     Type      |     Code      |          Checksum             |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                         Reachable Time                        |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                          Retrans Timer                        |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |   Options ...
>      +-+-+-+-+-+-+-+-+-+-+-+-
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
20]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    One notices that the Radiotap Header is not prepended, and that the
>    IEEE 802.11 Data Header and the Logical-Link Control Headers are =
not
>    present.  On another hand, a new header named Ethernet II Header is
>    present.
>=20
>    The Destination and Source addresses in the Ethernet II header
>    contain the same values as the fields Receiver Address and
>    Transmitter Address present in the IEEE 802.11 Data Header in the
>    "monitor" mode capture.
>=20
>    The value of the Type field in the Ethernet II header is 0x86DD
>    (recognized as "IPv6"); this value is the same value as the value =
of
>    the field Type in the Logical-Link Control Header in the "monitor"
>    mode capture.
>=20
>    The knowledgeable experimenter will no doubt notice the similarity =
of
>    this Ethernet II Header with a capture in normal mode on a pure
>    Ethernet cable interface.
>=20
>    It may be interpreted that an Adaptation layer is inserted in a =
pure
>    IEEE 802.11 MAC packets in the air, before delivering to the
>    applications.  In detail, this adaptation layer may consist in
>    elimination of the Radiotap, 802.11 and LLC headers and insertion =
of
>    the Ethernet II header.  In this way, it can be stated that IPv6 =
runs
>    naturally straight over LLC over the 802.11-OCB MAC layer, as shown
>    by the use of the Type 0x86DD, and assuming an adaptation layer
>    (adapting 802.11 LLC/MAC to Ethernet II header).
>=20
> 7 =
.  Security Considerations
>=20
>    Any security mechanism at the IP layer or above that may be carried
>    out for the general case of IPv6 may also be carried out for IPv6
>    operating over 802.11-OCB.
>=20
>    802.11-OCB does not provide any cryptographic protection, because =
it
>    operates outside the context of a BSS (no Association Request/
>    Response, no Challenge messages).  Any attacker can therefore just
>    sit in the near range of vehicles, sniff the network (just set the
>    interface card's frequency to the proper range) and perform attacks
>    without needing to physically break any wall.  Such a link is way
>    less protected than commonly used links (wired link or protected
>    802.11).
>=20
> [Sri] Per my earlier comment, there is more than one attack vector =
possible
> 1.) Absence of link-layer security and the potential for mac address =
spoofing=20
> 2.) IP address / Session hijacking=20
> 3.) Data privacy per your text
>=20
>=20
>    At the IP layer, IPsec can be used to protect unicast =
communications,
>    and SeND can be used for multicast communications.=20
>=20
> [Sri] IPSec can be used for protecting both multicast or unicast =
communication; RFC-5374 with GDOI.
>=20
>=20
>=20
>  If no protection
>    is used by the IP layer, upper layers should be protected.
>    Otherwise, the end-user or system should be warned about the risks
>    they run.
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
21]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    As with all Ethernet and 802.11 interface identifiers, there may
>    exist privacy risks in the use of 802.11-OCB interface identifiers.
>    Moreover, in outdoors vehicular settings, the privacy risks are =
more
>    important than in indoors settings.  New risks are induced by the
>    possibility of attacker sniffers deployed along routes which listen
>    for IP packets of vehicles passing by.  For this reason, in the
>    802.11-OCB deployments, there is a strong necessity to use =
protection
>    tools such as dynamically changing MAC addresses.  This may help
>    mitigate privacy risks to a certain level.  On another hand, it may
>    have an impact in the way typical IPv6 address auto-configuration =
is
>    performed for vehicles (SLAAC would rely on MAC addresses amd would
>    hence dynamically change the affected IP address), in the way the
>    IPv6 Privacy addresses were used, and other effects.
>=20
> 8 =
.  IANA Considerations
>=20
> 9 =
.  Contributors
>=20
>    Romain Kuntz contributed extensively about IPv6 handovers between
>    links running outside the context of a BSS (802.11-OCB links).
>=20
>    Tim Leinmueller contributed the idea of the use of IPv6 over
>    802.11-OCB for distribution of certificates.
>=20
>    Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey
>    Voronov provided significant feedback on the experience of using IP
>    messages over 802.11-OCB in initial trials.
>=20
>    Michelle Wetterwald contributed extensively the MTU discussion,
>    offered the ETSI ITS perspective, and reviewed other parts of the
>    document.
>=20
> 10 =
.  Acknowledgements
>=20
>    The authors would like to thank Witold Klaudel, Ryuji Wakikawa,
>    Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan
>    Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray
>    Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,
>    Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,
>    Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,
>    Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and
>    William Whyte.  Their valuable comments clarified certain issues =
and
>    generally helped to improve the document.
>=20
>    Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB
>    drivers for linux and described how.
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
22]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    For the multicast discussion, the authors would like to thank Owen
>    DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and
>    participants to discussions in network working groups.
>=20
>    The authours would like to thank participants to the Birds-of-
>    a-Feather "Intelligent Transportation Systems" meetings held at =
IETF
>    in 2016.
>=20
> 11 =
.  References
>=20
> 11.1 =
.  Normative References
>=20
>    [I-D.ietf-6man-default-iids <>]
>               Gont, F., Cooper, A., Thaler, D., and S. LIU,
>               "Recommendation on Stable IPv6 Interface Identifiers",
>               draft-ietf-6man-default-iids-16 =
 (work in =
progress),
>               September 2016.
>=20
>    [I-D.ietf-6man-ug <>]
>               Carpenter, B. and S. Jiang, "Significance of IPv6
>               Interface Identifiers", draft-ietf-6man-ug-06 =
 (work in
>               progress), December 2013.
>=20
>    [I-D.ietf-tsvwg-ieee-802-11 <>]
>               Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE
>               802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-06 =
 (work in
>               progress), August 2017.
>=20
>    [RFC1042 <>]  Postel, J. and J. Reynolds, "Standard for the =
transmission
>               of IP datagrams over IEEE 802 networks", STD 43, RFC =
1042 ,
>               DOI 10.17487/RFC1042, February 1988, 
>               editor.org/info/rfc1042 =
>.
>=20
>    [RFC2119 <>]  Bradner, S., "Key words for use in RFCs to Indicate
>               Requirement Levels", BCP 14 =
, RFC 2119 =
,
>               DOI 10.17487/RFC2119, March 1997, 
>               editor.org/info/rfc2119 =
>.
>=20
>    [RFC2460 <>]  Deering, S. and R. Hinden, "Internet Protocol, =
Version 6
>               (IPv6) Specification", RFC 2460 =
, DOI 10.17487/RFC2460,
>               December 1998, >.
>=20
>    [RFC2464 <>]  Crawford, M., "Transmission of IPv6 Packets over =
Ethernet
>               Networks", RFC 2464 =
, DOI 10.17487/RFC2464, December =
1998,
>               >.
>=20
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
23]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    [RFC3963 <>]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
>               Thubert, "Network Mobility (NEMO) Basic Support =
Protocol",
>               RFC 3963 , DOI =
10.17487/RFC3963, January 2005,
>               >.
>=20
>    [RFC4086 <>]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
>               "Randomness Requirements for Security", BCP 106 =
, RFC 4086 =
,
>               DOI 10.17487/RFC4086, June 2005, 
>               editor.org/info/rfc4086 =
>.
>=20
>    [RFC4301 <>]  Kent, S. and K. Seo, "Security Architecture for the
>               Internet Protocol", RFC 4301 =
, DOI 10.17487/RFC4301,
>               December 2005, >.
>=20
>    [RFC4429 <>]  Moore, N., "Optimistic Duplicate Address Detection =
(DAD)
>               for IPv6", RFC 4429 =
, DOI 10.17487/RFC4429, April 2006,
>               >.
>=20
>    [RFC4861 <>]  Narten, T., Nordmark, E., Simpson, W., and H. =
Soliman,
>               "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861 =
,
>               DOI 10.17487/RFC4861, September 2007, 
>               editor.org/info/rfc4861 =
>.
>=20
>    [RFC5889 <>]  Baccelli, E., Ed. and M. Townsley, Ed., "IP =
Addressing
>               Model in Ad Hoc Networks", RFC 5889 =
, DOI 10.17487/RFC5889,
>               September 2010, >.
>=20
>    [RFC6275 <>]  Perkins, C., Ed., Johnson, D., and J. Arkko, =
"Mobility
>               Support in IPv6", RFC 6275 =
, DOI 10.17487/RFC6275, July
>               2011, >.
>=20
>    [RFC6775 <>]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and =
C.
>               Bormann, "Neighbor Discovery Optimization for IPv6 over
>               Low-Power Wireless Personal Area Networks (6LoWPANs)",
>               RFC 6775 , DOI =
10.17487/RFC6775, November 2012,
>               >.
>=20
>    [RFC7721 <>]  Cooper, A., Gont, F., and D. Thaler, "Security and =
Privacy
>               Considerations for IPv6 Address Generation Mechanisms",
>               RFC 7721 , DOI =
10.17487/RFC7721, March 2016,
>               >.
>=20
> 11.2 =
.  Informative References
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
24]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    [fcc-cc <>]   "'Report and Order, Before the Federal Communications
>               Commission Washington, D.C. 20554', FCC 03-324, Released
>               on February 10, 2004, document FCC-03-324A1.pdf, =
document
>               freely available at URL
>               http://www.its.dot.gov/exit/fcc_edocs.htm =
 downloaded on
>               October 17th, 2013.".
>=20
>    [fcc-cc-172-184 <>]
>               "'Memorandum Opinion and Order, Before the Federal
>               Communications Commission Washington, D.C. 20554', FCC
>               06-10, Released on July 26, 2006, document FCC-
>               06-110A1.pdf, document freely available at URL
>               http://hraunfoss.fcc.gov/edocs_public/attachmatch/ =

>               FCC-06-110A1.pdf =
 =
downloaded on June 5th, 2014.".
>=20
>    [I-D.jeong-ipwave-vehicular-networking-survey <>]
>               Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M.
>               Wetterwald, "Survey on IP-based Vehicular Networking for
>               Intelligent Transportation Systems", draft-jeong-ipwave- =

>               vehicular-networking-survey-03 =
 (work in progress), June
>               2017.
>=20
>    [I-D.perkins-intarea-multicast-ieee802 <>]
>               Perkins, C., Stanley, D., Kumari, W., and J. Zuniga,
>               "Multicast Considerations over IEEE 802 Wireless Media",
>               draft-perkins-intarea-multicast-ieee802-03 =
 =
(work in
>               progress), July 2017.
>=20
>    [I-D.petrescu-its-scenarios-reqs <>]
>               Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel,
>               "Scenarios and Requirements for IP in Intelligent
>               Transportation Systems", draft-petrescu-its-scenarios- =

>               reqs-03 =
 (work =
in progress), October 2013.
>=20
>    [ieee1609.2 <>]
>               "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless =
Access
>               in Vehicular Environments (WAVE) -- Security Services =
for
>               Applications and Management Messages.  Example URL
>               http://ieeexplore.ieee.org/document/7426684/ =
 accessed on
>               August 17th, 2017.".
>=20
>    [ieee1609.3 <>]
>               "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless =
Access
>               in Vehicular Environments (WAVE) -- Networking Services.
>               Example URL http://ieeexplore.ieee.org/document/7458115/ =

>               accessed =
 on August 17th, =
2017.".
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
25]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    [ieee1609.4 <>]
>               "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless =
Access
>               in Vehicular Environments (WAVE) -- Multi-Channel
>               Operation.  Example URL
>               http://ieeexplore.ieee.org/document/7435228/ =
 accessed on
>               August 17th, 2017.".
>=20
>    [ieee802.11-2012 <>]
>               "802.11-2012 - IEEE Standard for Information =
technology--
>               Telecommunications and information exchange between
>               systems Local and metropolitan area networks--Specific
>               requirements Part 11: Wireless LAN Medium Access Control
>               (MAC) and Physical Layer (PHY) Specifications.  =
Downloaded
>               on October 17th, 2013, from IEEE Standards, document
>               freely available at URL
>               http://standards.ieee.org/findstds/ =

>               standard/802.11-2012.html =
 retrieved =
on October 17th,
>               2013.".
>=20
>    [ieee802.11p-2010 <>]
>               "IEEE Std 802.11p (TM)-2010, IEEE Standard for =
Information
>               Technology - Telecommunications and information exchange
>               between systems - Local and metropolitan area networks -
>               Specific requirements, Part 11: Wireless LAN Medium =
Access
>               Control (MAC) and Physical Layer (PHY) Specifications,
>               Amendment 6: Wireless Access in Vehicular Environments;
>               document freely available at URL
>               http://standards.ieee.org/getieee802/ =

>               download/802.11p-2010.pdf =
 =
retrieved on September 20th,
>               2013.".
>=20
> Appendix A =
.  ChangeLog
>=20
>    The changes are listed in reverse chronological order, most recent
>    changes appearing at the top of the list.
>=20
>    =46rom draft-ietf-ipwave-ipv6-over-80211ocb-03 =
 to =
draft-ietf-ipwave- =

>    ipv6-over-80211ocb-04 =

>=20
>    o  Removed a few informative references pointing to Dx draft IEEE
>       1609 documents.
>=20
>    o  Removed outdated informative references to ETSI documents.
>=20
>    o  Added citations to IEEE 1609.2, .3 and .4-2016.
>=20
>    o  Minor textual issues.
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
26]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    =46rom draft-ietf-ipwave-ipv6-over-80211ocb-02 =
 to =
draft-ietf-ipwave- =

>    ipv6-over-80211ocb-03 =

>=20
>    o  Keep the previous text on multiple addresses, so remove talk =
about
>       MIP6, NEMOv6 and MCoA.
>=20
>    o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.
>=20
>    o  Clarified the figure showing Infrastructure mode and OCB mode =
side
>       by side.
>=20
>    o  Added a reference to the IP Security Architecture RFC.
>=20
>    o  Detailed the IPv6-per-channel prohibition paragraph which =
reflects
>       the discussion at the last IETF IPWAVE WG meeting.
>=20
>    o  Added section "Address Mapping -- Unicast".
>=20
>    o  Added the ".11 Trailer" to pictures of 802.11 frames.
>=20
>    o  Added text about SNAP carrying the Ethertype.
>=20
>    o  New RSU definition allowing for it be both a Router and not
>       necessarily a Router some times.
>=20
>    o  Minor textual issues.
>=20
>    =46rom draft-ietf-ipwave-ipv6-over-80211ocb-01 =
 to =
draft-ietf-ipwave- =

>    ipv6-over-80211ocb-02 =

>=20
>    o  Replaced almost all occurences of 802.11p with 802.11-OCB, =
leaving
>       only when explanation of evolution was necessary.
>=20
>    o  Shortened by removing parameter details from a paragraph in the
>       Introduction.
>=20
>    o  Moved a reference from Normative to Informative.
>=20
>    o  Added text in intro clarifying there is no handover spec at =
IEEE,
>       and that 1609.2 does provide security services.
>=20
>    o  Named the contents the fields of the EthernetII header =
(including
>       the Ethertype bitstring).
>=20
>    o  Improved relationship between two paragraphs describing the
>       increase of the Sequence Number in 802.11 header upon IP
>       fragmentation.
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
27]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    o  Added brief clarification of "tracking".
>=20
>    =46rom draft-ietf-ipwave-ipv6-over-80211ocb-00 =
 to =
draft-ietf-ipwave- =

>    ipv6-over-80211ocb-01 =

>=20
>    o  Introduced message exchange diagram illustrating differences
>       between 802.11 and 802.11 in OCB mode.
>=20
>    o  Introduced an appendix listing for information the set of 802.11
>       messages that may be transmitted in OCB mode.
>=20
>    o  Removed appendix sections "Privacy Requirements", =
"Authentication
>       Requirements" and "Security Certificate Generation".
>=20
>    o  Removed appendix section "Non IP Communications".
>=20
>    o  Introductory phrase in the Security Considerations section.
>=20
>    o  Improved the definition of "OCB".
>=20
>    o  Introduced theoretical stacked layers about IPv6 and IEEE layers
>       including EPD.
>=20
>    o  Removed the appendix describing the details of prohibiting IPv6 =
on
>       certain channels relevant to 802.11-OCB.
>=20
>    o  Added a brief reference in the privacy text about a precise =
clause
>       in IEEE 1609.3 and .4.
>=20
>    o  Clarified the definition of a Road Side Unit.
>=20
>    o  Removed the discussion about security of WSA (because is =
non-IP).
>=20
>    o  Removed mentioning of the GeoNetworking discussion.
>=20
>    o  Moved references to scientific articles to a separate 'overview'
>       draft, and referred to it.
>=20
> Appendix B =
.  Changes Needed on a software driver 802.11a to become a
>              802.11-OCB driver
>=20
>    The 802.11p amendment modifies both the 802.11 stack's physical and
>    MAC layers but all the induced modifications can be quite easily
>    obtained by modifying an existing 802.11a ad-hoc stack.
>=20
>    Conditions for a 802.11a hardware to be 802.11-OCB compliant:
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
28]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    o  The chip must support the frequency bands on which the regulator
>       recommends the use of ITS communications, for example using IEEE
>       802.11-OCB layer, in France: 5875MHz to 5925MHz.
>=20
>    o  The chip must support the half-rate mode (the internal clock
>       should be able to be divided by two).
>=20
>    o  The chip transmit spectrum mask must be compliant to the =
"Transmit
>       spectrum mask" from the IEEE 802.11p amendment (but experimental
>       environments tolerate otherwise).
>=20
>    o  The chip should be able to transmit up to 44.8 dBm when used by
>       the US government in the United States, and up to 33 dBm in
>       Europe; other regional conditions apply.
>=20
>    Changes needed on the network stack in OCB mode:
>=20
>    o  Physical layer:
>=20
>       *  The chip must use the Orthogonal Frequency Multiple Access
>          (OFDM) encoding mode.
>=20
>       *  The chip must be set in half-mode rate mode (the internal =
clock
>          frequency is divided by two).
>=20
>       *  The chip must use dedicated channels and should allow the use
>          of higher emission powers.  This may require modifications to
>          the regulatory domains rules, if used by the kernel to =
enforce
>          local specific restrictions.  Such modifications must respect
>          the location-specific laws.
>=20
>       MAC layer:
>=20
>       *  All management frames (beacons, join, leave, and others)
>          emission and reception must be disabled except for frames of
>          subtype Action and Timing Advertisement (defined below).
>=20
>       *  No encryption key or method must be used.
>=20
>       *  Packet emission and reception must be performed as in ad-hoc
>          mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).
>=20
>       *  The functions related to joining a BSS (Association Request/
>          Response) and for authentication (Authentication =
Request/Reply,
>          Challenge) are not called.
>=20
>       *  The beacon interval is always set to 0 (zero).
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
29]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>       *  Timing Advertisement frames, defined in the amendment, should
>          be supported.  The upper layer should be able to trigger such
>          frames emission and to retrieve information contained in
>          received Timing Advertisements.
>=20
> Appendix C =
.  Design Considerations
>=20
>    The networks defined by 802.11-OCB are in many ways similar to =
other
>    networks of the 802.11 family.  In theory, the encapsulation of =
IPv6
>    over 802.11-OCB could be very similar to the operation of IPv6 over
>    other networks of the 802.11 family.  However, the high mobility,
>    strong link asymetry and very short connection makes the 802.11-OCB
>    link significantly different from other 802.11 networks.  Also, the
>    automotive applications have specific requirements for reliability,
>    security and privacy, which further add to the particularity of the
>    802.11-OCB link.
>=20
> C.1 =
.  Vehicle ID
>=20
>    Automotive networks require the unique representation of each of
>    their node.  Accordingly, a vehicle must be identified by at least
>    one unique identifier.  The current specification at ETSI and at =
IEEE
>    1609 identifies a vehicle by its MAC address uniquely obtained from
>    the 802.11-OCB NIC.
>=20
>    A MAC address uniquely obtained from a IEEE 802.11-OCB NIC
>    implicitely generates multiple vehicle IDs in case of multiple
>    802.11-OCB NICs.  A mechanims to uniquely identify a vehicle
>    irrespectively to the different NICs and/or technologies is =
required.
>=20
> C.2 =
.  Reliability Requirements
>=20
>    The dynamically changing topology, short connectivity, mobile
>    transmitter and receivers, different antenna heights, and many-to-
>    many communication types, make IEEE 802.11-OCB links significantly
>    different from other IEEE 802.11 links.  Any IPv6 mechanism =
operating
>    on IEEE 802.11-OCB link MUST support strong link asymetry, spatio-
>    temporal link quality, fast address resolution and transmission.
>=20
>    IEEE 802.11-OCB strongly differs from other 802.11 systems to =
operate
>    outside of the context of a Basic Service Set.  This means in
>    practice that IEEE 802.11-OCB does not rely on a Base Station for =
all
>    Basic Service Set management.  In particular, IEEE 802.11-OCB SHALL
>    NOT use beacons.  Any IPv6 mechanism requiring L2 services from =
IEEE
>    802.11 beacons MUST support an alternative service.
>=20
>=20
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
30]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
>    implement a mechanism for transmitter and receiver to converge to a
>    common channel.
>=20
>    Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST
>    implement an distributed mechanism to authenticate transmitters and
>    receivers without the support of a DHCP server.
>=20
>    Time synchronization not being available, IPv6 over IEEE 802.11-OCB
>    MUST implement a higher layer mechanism for time synchronization
>    between transmitters and receivers without the support of a NTP
>    server.
>=20
>    The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB
>    MUST disable management mechanisms requesting acknowledgements or
>    replies.
>=20
>    The IEEE 802.11-OCB link having a short duration time, IPv6 over =
IEEE
>    802.11-OCB MUST implement fast IPv6 mobility management mechanisms.
>=20
> C.3 =
.  Multiple interfaces
>=20
>    There are considerations for 2 or more IEEE 802.11-OCB interface
>    cards per vehicle.  For each vehicle taking part in road traffic, =
one
>    IEEE 802.11-OCB interface card could be fully allocated for Non IP
>    safety-critical communication.  Any other IEEE 802.11-OCB may be =
used
>    for other type of traffic.
>=20
>    The mode of operation of these other wireless interfaces is not
>    clearly defined yet.  One possibility is to consider each card as =
an
>    independent network interface, with a specific MAC Address and a =
set
>    of IPv6 addresses.  Another possibility is to consider the set of
>    these wireless interfaces as a single network interface (not
>    including the IEEE 802.11-OCB interface used by Non IP safety
>    critical communications).  This will require specific logic to
>    ensure, for example, that packets meant for a vehicle in front are
>    actually sent by the radio in the front, or that multiple copies of
>    the same packet received by multiple interfaces are treated as a
>    single packet.  Treating each wireless interface as a separate
>    network interface pushes such issues to the application layer.
>=20
>    The privacy requirements of [] imply that if these multiple
>    interfaces are represented by many network interface, a single
>    renumbering event SHALL cause renumbering of all these interfaces.
>    If one MAC changed and another stayed constant, external observers
>    would be able to correlate old and new values, and the privacy
>    benefits of randomization would be lost.
>=20
>=20
>=20
>=20
> Petrescu, et al.        Expires February 18, 2018              [Page =
31]
>   =

> Internet-Draft             IPv6-over-80211ocb                August =
2017
>=20
>=20
>    The privacy requirements of Non IP safety-critical communications
>    imply that if a change of pseudonyme occurs, renumbering of all =
other
>    interfaces SHALL also occur.
>=20
> C.4 =
.  MAC Address Generation
>=20
>    When designing the IPv6 over 802.11-OCB address mapping, we will
>    assume that the MAC Addresses will change during well defined
>    "renumbering events".  The 48 bits randomized MAC addresses will =
have
>    the following characteristics:
>=20
>    o  Bit "Local/Global" set to "locally admninistered".
>=20
>    o  Bit "Unicast/Multicast" set to "Unicast".
>=20
>    o  46 remaining bits set to a random value, using a random number
>       generator that meets the requirements of [RFC4086 =
].
>=20
>    The way to meet the randomization requirements is to retain 46 bits
>    from the output of a strong hash function, such as SHA256, taking =
as
>    input a 256 bit local secret, the "nominal" MAC Address of the
>    interface, and a representation of the date and time of the
>    renumbering event.
>=20
> Appendix D =
.  IEEE 802.11 Messages Transmitted in OCB mode
>=20
>    For information, at the time of writing, this is the list of IEEE
>    802.11 messages that may be transmitted in OCB mode, i.e. when
>    dot11OCBActivated is true in a STA:
>=20
>    o  The STA may send management frames of subtype Action and, if the
>       STA maintains a TSF Timer, subtype Timing Advertisement;
>=20
>    o  The STA may send control frames, except those of subtype =
PS-Poll,
>       CF-End, and CF-End plus CFAck;
>=20
>    o  The STA may send data frames of subtype Data, Null, QoS Data, =
and
>       QoS Null.
>=20
> Authors' Addresses
>=20
> _______________________________________________
> its mailing list
> its@ietf.org
> https://www.ietf.org/mailman/listinfo/its


--Apple-Mail=_2A698E3D-0402-48E1-A6FF-6D8918E7C164
Content-Transfer-Encoding: quoted-printable
Content-Type: text/html;
	charset=utf-8

Thanks very much.  These questions make me wonder =
whether there are different answers depending on motion.  If the =
vehicle is parked, a different set of solutions might be desirable.

Russ


On =
Aug 27, 2017, at 11:00 PM, Sri Gundavelli (sgundave) <sgundave@cisco.com> =
wrote:













Attached is my review feedback. 







In general there is lot of good information in the =
document. But, there are also few areas where additional clarifications =
will greatly help.







1.) Its not clear, if the document makes any assumption =
on the operating environment/communication profile. There is not much =
discussion on that aspect; For example, Is it always a one-hop =
communication between RSU and OBU where the 802.11-OCB link?  So,
 is the use of IPv6 only in that context of 1-hop =
communication? 







2.) There is also no discussion on how these links get =
formed in vehicular environment and when they are =
attached/detached. 







3.) How do nodes discover each other?  How does ND =
resolution work? Are these messages received by a multiple RSU=E2=80=99s, =
or a single RSU? Whats the implication of that. Note that you don=E2=80=99=
t have that issue in 802.11, given the association to an access point,
 which in turn maps the links to a VLAN/subnet.







4.) What happens as a vehicle moves between RSU=E2=80=99s,=
 how does it impact address configuration?   Is DHCPv6 based =
address configuration relevant here?












 Please see inline for additional comments.










---------------------------------------------------------------=
---

 
Transmission of IPv6 =
Packets over IEEE 802.11 Networks in mode Outside

        
the Context of a Basic =
Service Set (IPv6-over-80211ocb)

              
draft-ietf-ipwave-ipv6-over-80211ocb-04.txt






[Sri] May be change to, =E2=80=9C..in mode .." =E2=80=94> =E2=80=9C..operating in mode ..=E2=80=9D  ?






Abstract

   In order to transmit IPv6 packets on IEEE 802.11 networks run outside
   the context of a basic service set (OCB, earlier "802.11p") there is
   a need to define a few parameters such as the recommended Maximum
   Transmission Unit size, the header format preceding the IPv6 header,
   the Type value within it, and others.  This document describes these
   parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
   layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
   Ethernet layers - by using an Ethernet Adaptation Layer.



[Sri] Is it =E2=80=9Crecommended MTU size", or =
"supported MTU size on the 802.11 OCB link?  






  =
 In addition, the document attempts to list what is different in
   802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
   layers, layers over which IPv6 protocols operates without issues.
   Most notably, the operation outside the context of a BSS (OCB) has
   impact on IPv6 handover behaviour and on IPv6 security.



[Sri] Minor =
comment. May be instead of using the =E2=80=9Clayer=E2=80=9D =
terminology, you may want to present this as IPv6 support on "802.11 =
OCB" links. 




  =
 An example of an IPv6 packet captured while transmitted over an IEEE
   802.11 OCB link (802.11p) is given.



[Sri] Last paragraph can be =
ommitted in my view. That=E2=80=99s too much of detail for =
Abstract.




Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute



Petrescu, et =
al.        Expires February 18, 2018               [Page 1]




 
Internet-Draft =
            IPv6-over-80211ocb                August 2017


   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 18, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the =
IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the =
date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . =
. . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . =
. . . . . . . . . . .   5
   3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    6
   4.  Aspects introduced by the OCB mode to =
802.11  . . . . . . . .   6
   5.  Layering of IPv6 over 802.11-OCB as over =
Ethernet . . . . . .  10
     5.1.  Maximum Transmission Unit (MTU) . . =
. . . . . . . . . . .  10
     5.2.  Frame Format  . . . . . . . . . . . =
. . . . . . . . . . .  11
       5.2.1.  Ethernet Adaptation Layer . . . =
. . . . . . . . . . .  12
     5.3.  Link-Local Addresses  . . . . . . . =
. . . . . . . . . . .  13
     5.4.  Address Mapping . . . . . . . . . . =
. . . . . . . . . . .  14
       5.4.1.  Address Mapping -- Unicast  . . =
. . . . . . . . . . .  14
       5.4.2.  Address Mapping -- Multicast  . =
. . . . . . . . . . .  14
     5.5.  Stateless Autoconfiguration . . . . =
. . . . . . . . . . .  15
     5.6.  Subnet Structure  . . . . . . . . . =
. . . . . . . . . . .  16
   6.  Example IPv6 Packet captured over a IEEE =
802.11-OCB link  . .  16
     6.1.  Capture in Monitor Mode . . . . . . =
. . . . . . . . . . .  17
     6.2.  Capture in Normal Mode  . . . . . . =
. . . . . . . . . . .  19
   7.  Security Considerations . . . . . . . . =
. . . . . . . . . . .  21
   8.  IANA Considerations . . . . . . . . . . =
. . . . . . . . . . .  22
   9.  Contributors  . . . . . . . . . . . . . =
. . . . . . . . . . .  22
   10. Acknowledgements  . . . . . . . . . . . =
. . . . . . . . . . .  22



Petrescu, et =
al.        Expires February 18, 2018               [Page 2]




 
Internet-Draft =
            IPv6-over-80211ocb                August 2017


   11. References  . . . . . . . . . . . . . . =
. . . . . . . . . . .  23
     11.1.  Normative References . . . . . . . =
. . . . . . . . . . .  23
     11.2.  Informative References . . . . . . =
. . . . . . . . . . .  24
   Appendix A.  ChangeLog  . . . . . . . . . . =
. . . . . . . . . . .  26
   Appendix B.  Changes Needed on a software =
driver 802.11a to
                become a                     802.11-OCB driver . . .  28
   Appendix C.  Design Considerations  . . . . =
. . . . . . . . . . .  30
     C.1.  Vehicle ID  . . . . . . . . . . . . =
. . . . . . . . . . .  30
     C.2.  Reliability Requirements  . . . . . =
. . . . . . . . . . .  30
     C.3.  Multiple interfaces . . . . . . . . =
. . . . . . . . . . .  31
     C.4.  MAC Address Generation  . . . . . . =
. . . . . . . . . . .  32
   Appendix D.  IEEE 802.11 Messages =
Transmitted in OCB mode . . . .  32
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  32


1.  =
Introduction


   This document describes the transmission of IPv6 packets on IEEE Std
   802.11 OCB networks (earlier known as 802.11p).  





[Sri] Please add a reference to =
the IEEE specification that defines the OCB mode. =









This involves the
   layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with
   an LLC layer).  Compared to running IPv6 over the Ethernet MAC layer,
   there is no modification required to the standards: IPv6 works fine
   directly over 802.11 OCB too (with an LLC layer).

   The term "802.11p" is an earlier definition.  As of year 2012, the
   behaviour of "802.11p" networks has been rolled in the document IEEE
   Std 802.11-2012.  In this document the term 802.11p disappears.
   Instead, each 802.11p feature is conditioned by a flag in the
   Management Information Base.  That flag is named "OCBActivated".
   Whenever OCBActivated is set to true the feature it relates to
   represents an earlier 802.11p feature.  For example, an 802.11
   STAtion operating outside the context of a basic service set has the
   OCBActivated flag set.  Such a station, when it has the flag set, it
   uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.

   In the following text we use the term "802.11p" to mean 802.11-2012
   OCB.

   The IPv6 network layer operates on 802.11 OCB in the same manner as
   it operates on 802.11 WiFi, with a few particular exceptions.  The
   IPv6 network layer operates on WiFi by involving an Ethernet
   Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers
   to Ethernet II headers.  The operation of IP on Ethernet is described
   in [RFC1042] and [RFC2464].  =
The situation of IPv6 networking layer
   on Ethernet Adaptation Layer is illustrated below:







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                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |                 IPv6                  |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |       Ethernet Adaptation Layer       |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi MAC           |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi PHY           |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   (in the above figure, a WiFi profile is represented; this is used
   also for OCB profile.)

   A more theoretical and detailed view of layer stacking, and
   interfaces between the IP layer and 802.11 OCB layers, is illustrated
   below.  The IP layer operates on top of the EtherType Protocol
   Discrimination (EPD); this Discrimination layer is described in IEEE
   Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP
   (Link Layer Control Service Accesss Point).


           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           |                 IPv6                  |
           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+
                       {   LLC_SAP  }                 802.11 OCB
           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+  Boundary
           |            EPD          |       |     |
           |                         | MLME  |     |
           +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   |
           |      MAC Sublayer       |       |     |  802.11 OCB
           |     and ch. coord.      |       | SME |  Services
           +-+-+-{   PHY_SAP  }+-+-+-+-+-+-+-|     |
           |                         | PLME  |     |
           |            PHY Layer    |   PLME_SAP  |
           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   In addition to the description of interface between IP and MAC using
   "Ethernet Adaptation Layer" and "Ethernet Protocol Discrimination
   (EPD)" it is worth mentioning that SNAP [RFC1042] is used to carry
   the IPv6 Ethertype.

   However, there may be some deployment considerations helping optimize
   the performances of running IPv6 over 802.11-OCB (e.g. in the case of
   handovers between 802.11 OCB-enabled access routers, or the
   consideration of using the IP security layer [RFC4301]).




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   There are currently no specifications for handover between OCB links
   since these are currently specified as LLC-1 links (i.e.
   connectionless).  Any handovers must be performed above the Data Link
   Layer.  Also, while there is no encryption applied below the network
   layer using 802.11p, 1609.2 [ieee1609.2] does provide security
   services for applications to use so that there can easily be data
   security over the air without invoking IPsec.

   We briefly introduce the vehicular communication scenarios where IEEE
   802.11-OCB links are used. 





[Sri] I have not seen much =
discussion on the link / communication assumptions. =









 =
This is followed by a description of
   differences in specification terms, between 802.11 OCB and
   802.11a/b/g/n (and the same differences expressed in terms of
   requirements to software implementation are listed in Appendix B.)

   The document then concentrates on the parameters of layering IP over
   802.11 OCB as over Ethernet: value of MTU, the contents of Frame
   Format, the rules for forming Interface Identifiers, the mechanism
   for Address Mapping and for State-less Address Auto-configuration.
   These are precisely the same as IPv6 over Ethernet [RFC2464].

   As an example, these characteristics of layering IPv6 straight over
   LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet
   captured over a 802.11 OCB link; this is described in the section
   Section 6.

   A couple of points can be considered as different, although they are
   not required in order to have a working implementation of IPv6-over-
   802.11-OCB.  These points are consequences of the OCB operation which
   is particular to 802.11 OCB (Outside the Context of a BSS).  First,
   the handovers between OCB links need specific behaviour for IP Router
   Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of
   higher layer messages such as the 'Basic Safety Message' (in the US)
   or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE
   Routing Advertisement'; second, the IP security mechanisms are
   necessary, since OCB means that 802.11 is stripped of all 802.11
   link-layer security; a small additional security aspect which is
   shared between 802.11 OCB and other 802.11 links is the privacy
   concerns related to the address formation mechanisms.

   In the published literature, many documents describe aspects related
   to running IPv6 over 802.11 OCB:
   [I-D.jeong-ipwave-vehicular-networking-survey].


2.  =
Terminology


   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].



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   RSU: Road Side Unit.  A computer equipped with at least one IEEE
   802.11 interface operated in OCB mode.  This definition applies to
   this document.  An RSU may be connected to the Internet, and may be
   equipped with additional wired or wireless network interfaces running
   IP.  An RSU MAY be an IP Router.






[Sri] RSU can be compared to an =
802.11 access point; Or, WTP as defined in CAPWAP specification, =
RFC5415.

=


Perhaps. rephrase as below?:





"RSU: =
Road Side Unit. Its a wireless termination point (WTP), as defined in =
RFC5415 with one key difference, where the wireless physical and the mac layer is configured to operate =
in 802.11 OCB mode.  The RSU communicates with the On board Unit (OBU) in the vehicle over 802.11 wireless link =
operating in OCB mode.=E2=80=9D 








** Also, since you are defining =
the RSU term, should you also not define OBU (On board Unit) in the =
vehicle which is the entity on the other end of the link? =E2=80=9CRSU =
----802.11-OCB=E2=80=94=E2=80=94OBU=E2=80=9D ? May be introduce the OCB =
definition separately, just as you did with RSU, and show the =
communication link as 802.11-OCB.






  =
 OCB: outside the context of a basic service set (BSS): A mode of
   operation in which a STA is not a member of a BSS and does not
   utilize IEEE Std 802.11 authentication, association, or data
   confidentiality.

   802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is
   flagged by "dot11OCBActivated".  This means: IEEE 802.11e for quality
   of service; 802.11j-2004 for half-clocked operations; and (what was
   known earlier as) 802.11p for operation in the 5.9 GHz band and in
   mode OCB.






[Sri] The text starting with. =E2=80=9CThis means=E2=80=9D is =
not clear to me. Does it 802.11e is supported with 802.11OCB mode. =
Please clarify






3.  Communication =
Scenarios where IEEE 802.11 OCB Links are Used


   The IEEE 802.11 OCB Networks are used for vehicular communications,
   as 'Wireless Access in Vehicular Environments'.  The IP communication
   scenarios for these environments have been described in several
   documents, among which we refer the reader to one recently updated
   [I-D.petrescu-its-scenarios-reqs], about scenarios and =
requirements
   for IP in Intelligent Transportation Systems.






[Sri] You can do bit more justice to this =
section. 
Explain the link model.  =E2=80=9CSTA ----802.11-OCB=E2=80=94=E2=80=94STA=E2=80=9D. =
Then talk about the applicability in Vehicular networks, with STA's as =
RSU and OCB.


You may also want to talk about, how links get =
formed/terminated; how nodes peer/discover and how mobility works ..etc. =
 While 802.11-OCB is clearly specified and the use of IPv6 over such =
link is also not radically new, but the operating environment which is =
vehicular brings many new things. That description is not present any =
where.





4.  Aspects introduced =
by the OCB mode to 802.11


   In the IEEE 802.11 OCB mode, all nodes in the wireless range can
   directly communicate with each other without authentication/
   association procedures.  Briefly, the IEEE 802.11 OCB mode has the
   following properties:








[Sri] Can you add some text on how =
nodes (ST1 and STA2) discover each other on such links supporting 802.11 =
OCB mode.


  =
 o  The use by each node of a 'wildcard' BSSID (i.e., each bit of the
      BSSID is set to 1)

   o  No IEEE 802.11 Beacon frames transmitted

   o  No authentication required

   o  No association needed

   o  No encryption provided





[Sri] Can you =
clarify what you mean when you say =E2=80=9CNo xxx required=E2=80=9D / =E2=80=9CNo xxx needed=E2=80=9D  for the above =
capabilities.  What does =E2=80=9Cneeded=E2=80=9D or =E2=80=9Crequire=
d=E2=80=9D mean?  Does it mean, =E2=80=9CAuthentication", =E2=80=9CAssociation" =
and =E2=80=9CEncryption=E2=80=9D is optional on this link, or that its =
not supported on 802.11 OCB links.  





  =
 o  Flag dot11OCBActivated set to true

   The following message exchange diagram illustrates a comparison
   between traditional 802.11 and 802.11 in OCB mode.  The 'Data'



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   messages can be IP messages such as the messages used in Stateless or
   Stateful Address Auto-Configuration, or other IP messages. =
 








[Sri] Lets separate the discussion =
on IP Address configuration using SLAAC/DHCP on such links from the =
above description. The Data packets here can be application packets such =
as HTTP or other packets. May be additional discussion is needed on the =
IP address configuration on 802.11-OCB links. 








Other
   802.11 management and control frames (non IP) may be transmitted, as
   specified in the 802.11 standard.  For information, the names of
   these messages as currently specified by the 802.11 standard are
   listed in Appendix D.


















  =
   STA                    AP              STA1                   STA2
     |                      |               |                      |
     |<------ Beacon -------|               |<------ Data =
-------->|
     |                      |               |                      |
     |---- Probe Req. ----->|               |<------ Data =
-------->|
     |<--- Probe Res. ------|               |                      |
     |                      |               |<------ Data =
-------->|
     |---- Auth Req. ------>|               |                      |
     |<--- Auth Res. -------|               |<------ Data =
-------->|
     |                      |               |                      |
     |---- Asso Req. ------>|               |<------ Data =
-------->|
     |<--- Asso Res. -------|               |                      |
     |                      |               |<------ Data =
-------->|
     |<------ Data -------->|               |                      =
|
     |<------ Data -------->|               |<------ Data =
-------->|

    (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode


   The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010
   [ieee802.11p-2010] as an amendment =
to IEEE Std 802.11 (TM) -2007,
   titled "Amendment 6: Wireless Access in Vehicular Environments".
   Since then, this amendment has been included in IEEE 802.11(TM)-2012
   [ieee802.11-2012], titled "IEEE =
Standard for Information technology--
   Telecommunications and information exchange between systems Local and
   metropolitan area networks--Specific requirements Part 11: Wireless
   LAN Medium Access Control (MAC) and Physical Layer (PHY)
   Specifications"; the modifications are diffused throughout various
   sections (e.g. the Time Advertisement message described in the
   earlier 802.11 (TM) p amendment is now described in section 'Frame
   formats', and the operation outside the context of a BSS described in
   section 'MLME').

   In document 802.11-2012, specifically anything referring
   "OCBActivated", or "outside the context of a basic service set" is
   actually referring to the 802.11p aspects introduced to 802.11.  Note
   that in earlier 802.11p documents the term "OCBEnabled" was used
   instead of te current "OCBActivated".





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   In order to delineate the aspects introduced by 802.11 OCB to 802.11,
   we refer to the earlier [ieee802.11p-2010].  The amendment =
is
   concerned with vehicular communications, where the wireless link is
   similar to that of Wireless LAN (using a PHY layer specified by
   802.11a/b/g/n), but which needs to cope with the high mobility factor
   inherent in scenarios of communications between moving vehicles, and
   between vehicles and fixed infrastructure deployed along roads.
   While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is
   concerned more with MAC modifications, and a little with PHY
   modifications; the others are mainly about PHY modifications.  It is
   possible in practice to combine a 'p' MAC with an 'a' PHY by
   operating outside the context of a BSS with OFDM at 5.4GHz.

   The 802.11 OCB links are specified to be compatible as much as
   possible with the behaviour of 802.11a/b/g/n and future generation
   IEEE WLAN links.  =46rom the IP perspective, an 802.11 =
OCB MAC layer
   offers practically the same interface to IP as the WiFi and Ethernet
   layers do (802.11a/b/g/n and 802.3).






[Sri] A packet sent from a =
vehicle=E2=80=99s OBU is received by a single RSU, or multiple RSU=E2=80=99=
s? How does the link-layer resolution happen?





  =
 To support this similarity statement (IPv6 is layered on top of LLC
   on top of 802.11 OCB similarly as on top of LLC on top of
   802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to
   analyze the differences between 802.11 OCB and 802.11 specifications.
   Whereas the 802.11p amendment specifies relatively complex and
   numerous changes to the MAC layer (and very little to the PHY layer),
   we note there are only a few characteristics which may be important
   for an implementation transmitting IPv6 packets on 802.11 OCB links.

   In the list below, the only 802.11 OCB fundamental points which
   influence IPv6 are the OCB operation and the 12Mbit/s maximum which
   may be afforded by the IPv6 applications.






[Sri] I am really =
not sure how link throughput (12Mbps) relates to "IPv6 support on OCB =
links".  








  =
 o  Operation Outside the Context of a BSS (OCB): the (earlier
      802.11p) 802.11-OCB links are operated without a Basic Service Set
      (BSS).  This means that the frames IEEE 802.11 Beacon, Association
      Request/Response, Authentication Request/Response, and similar,
      are not used.  The used identifier of BSS (BSSID) has a
      hexadecimal value always 0xffffffffffff (48 '1' bits, represented
      as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'
      BSSID), as opposed to an arbitrary BSSID value set by
      administrator (e.g.  'My-Home-AccessPoint').  The OCB operation -
      namely the lack of beacon-based scanning and lack of
      authentication - has a potentially strong impact on the use of the
      Mobile IPv6 protocol [RFC6275] and on the =
protocols for IP layer
      security [RFC4301].






[Sri] The =
document till now has been arguing heavily on how IPv6 operates so =
naturally on these links and now I see discussion on =E2=80=9CImpact to =
a high-level protocol such as =
MIPv6=E2=80=9D. You may want to fix the earlier text. In any case,  the =
absence of link-layer security practically impacts every application, =
not just MIPv6.  Also, MIPv6 does not make any assumptions on the =
link-layer security.  Also, the the 0xFF-FF-FF-FF-FF-FF as the BSSID, =
makes the messages readable by all other RSU=E2=80=99s in proximity. I =
think the discussion on the nature of the link, who all see=E2=80=99s =
the messages.. how L2 addresses are resolved is not explained clearly. =












  =
 o  Timing Advertisement: is a new message defined in 802.11-OCB,
      which does not exist in 802.11a/b/g/n.  This message is used by



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      stations to inform other stations about the value of time.  It is
      similar to the time as delivered by a GNSS system (Galileo, GPS,
      ...) or by a cellular system.  This message is optional for
      implementation.  At the date of writing, an =
experienced reviewer
      considers that currently no field testing has used this message.
      Another implementor considers this feature implemented in an
      initial manner.  In the future, it is speculated that this message
      may be useful for very simple devices which may not have their own
      hardware source of time (Galileo, GPS, cellular network), or by
      vehicular devices situated in areas not covered by such network
      (in tunnels, underground, outdoors but shaded by foliage or
      buildings, in remote areas, etc.)






[Sri] The first part explaining Timing Advertisement messages =
is great, but the rest of the commentary is unnecessary and not needed. =
We don=E2=80=99t speculate the protocol adoption success in IETF =
specifications, or about the experience level of the =E2=80=9Creviewer" =
:)








  =
 o  Frequency range: this is a characteristic of the PHY layer, with
      almost no impact to the interface between MAC and IP.  However, it
      is worth considering that the frequency range is regulated by a
      regional authority (ARCEP, ETSI, FCC, etc.); as part of the
      regulation process, specific applications are associated with
      specific frequency ranges.  In the case of 802.11-OCB, the
      regulator associates a set of frequency ranges, or slots within a
      band, to the use of applications of vehicular communications, in a
      band known as "5.9GHz".  This band is "5.9GHz" which is different
      from the bands "2.4GHz" or "5GHz" used by Wireless LAN.  However,
      as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz"
      bands is exempt from owning a license in EU (in US the 5.9GHz is a
      licensed band of spectrum; for the the fixed infrastructure an
      explicit FCC autorization is required; for an onboard device a
      'licensed-by-rule' concept applies: rule certification conformity
      is required); however technical conditions are different than
      those of the bands "2.4GHz" or "5GHz".  On one hand, the allowed
      power levels, and implicitly the maximum allowed distance between
      vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20
      dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum
      distance of approximately 1km, compared to approximately 50m.  On
      the other hand, specific conditions related to congestion
      avoidance, jamming avoidance, and radar detection are imposed on
      the use of DSRC (in US) and on the use of frequencies for
      Intelligent Transportation Systems (in EU), compared to Wireless
      LAN (802.11a/b/g/n).

   o  Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB,
      as opposed to IPv6 not being prohibited on any channel on which
      802.11a/b/g/n runs:

      *  Some channels are reserved for safety communications; the IPv6
         packets should not be sent on these channels.





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      *  At the time of writing, the prohibition is explicit at higher
         layer protocols providing services to the application; these
         higher layer protocols are specified in IEEE 1609 documents.

      *  National or regional specifications and regulations specify the
         use of different channels; these regulations must be followed.

   o  'Half-rate' encoding: as the frequency range, this parameter is
      related to PHY, and thus has not much impact on the interface
      between the IP layer and the MAC layer.

   o  In vehicular communications using 802.11-OCB links, there are
      strong privacy requirements with respect to addressing.  While the
      802.11-OCB standard does not specify anything in particular with
      respect to MAC addresses, in these settings there exists a strong
      need for dynamic change of these addresses (as opposed to the non-
      vehicular settings - real wall protection - where fixed MAC
      addresses do not currently pose some privacy risks).  This is
      further described in section Section 7.  A relevant function is
      described in IEEE 1609.3-2016 [ieee1609.3], clause 5.5.1 and IEEE
      1609.4-2016 [ieee1609.4], clause 6.7.






  =
 Other aspects particular to 802.11-OCB which are also particular to
   802.11 (e.g. the 'hidden node' operation) may have an influence on
   the use of transmission of IPv6 packets on 802.11-OCB networks.  The
   subnet structure which may be assumed in 802.11-OCB networks is
   strongly influenced by the mobility of vehicles.






[Sri] Per my earlier comment, the link model, addressing =
..etc needs to be explained in more detail. It is not clear what exactly =
the =E2=80=9Csubnet structure=E2=80=9D that is assumed in =
802.11-OCB.





5.  Layering of IPv6 =
over 802.11-OCB as over Ethernet



5.1.  Maximum =
Transmission Unit (MTU)


   The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is
   the same value as IPv6 packets on Ethernet links, as specified in
   [RFC2464].  This value of the MTU respects =
the recommendation that
   every link in the Internet must have a minimum MTU of 1280 octets
   (stated in [RFC2460], and the recommendations therein, especially
   with respect to fragmentation).  If IPv6 packets of size larger than
   1500 bytes are sent on an 802.11-OCB interface card then the IP stack
   will fragment.  In case there are IP fragments, the field "Sequence
   number" of the 802.11 Data header containing the IP fragment field is
   increased.

   Non-IP packets such as WAVE Short Message Protocol (WSMP) can be
   delivered on 802.11-OCB links.  Specifications of these packets are
   out of scope of this document, and do not impose any limit on the MTU
   size, allowing an arbitrary number of 'containers'.  Non-IP packets
   such as ETSI 'geonet' packets have an MTU of 1492 bytes.



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   The Equivalent Transmit Time on Channel is a concept that may be used
   as an alternative to the MTU concept.  A rate of transmission may be
   specified as well.  The ETTC, rate and MTU may be in direct
   relationship.



[Sri] The last paragraph needs some additional context. Did =
802.11-OCB introduce ETTC concept?  











5.2.  Frame =
Format


   IP packets are transmitted over 802.11-OCB as standard Ethernet
   packets.  As with all 802.11 frames, an Ethernet adaptation layer is
   used with 802.11-OCB as well.  This Ethernet Adaptation Layer
   performing 802.11-to-Ethernet is described in Section 5.2.1.  The
   Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD,
   or otherwise #86DD).

   The Frame format for transmitting IPv6 on 802.11-OCB networks is the
   same as transmitting IPv6 on Ethernet networks, and is described in
   section 3 of [RFC2464].  The frame format for =
transmitting IPv6
   packets over Ethernet is illustrated below:


                    0                   1
                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |          Destination          |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |             Source            |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |             IPv6              |
                    +-                             -+
                    |            header             |
                    +-                             -+
                    |             and               |
                    +-                             -+
                    /            payload ...        /
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    (Each tic mark represents one bit.)





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   Ethernet II Fields:

   Destination Ethernet Address
      the MAC destination address.

   Source Ethernet Address
      the MAC source address.

   1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
      binary representation of the EtherType value 0x86DD.

   IPv6 header and payload
      the IPv6 packet containing IPv6 header and payload.


5.2.1.  Ethernet =
Adaptation Layer


   In general, an 'adaptation' layer is inserted between a MAC layer and
   the Networking layer.  This is used to transform some parameters
   between their form expected by the IP stack and the form provided by
   the MAC layer.  For example, an 802.15.4 adaptation layer may perform
   fragmentation and reassembly operations on a MAC whose maximum Packet
   Data Unit size is smaller than the minimum MTU recognized by the IPv6
   Networking layer.  Other examples involve link-layer address
   transformation, packet header insertion/removal, and so on.

   An Ethernet Adaptation Layer makes an 802.11 MAC look to IP
   Networking layer as a more traditional Ethernet layer.  At reception,
   this layer takes as input the IEEE 802.11 Data Header and the
   Logical-Link Layer Control Header and produces an Ethernet II Header.
   At sending, the reverse operation is performed.


 +--------------------+------------+-------------+---------+-----------+
 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer|
 +--------------------+------------+-------------+---------+-----------+
  \                               /                         \         /
    -----------------------------                             --------
                   ^---------------------------------------------/
                   |
           802.11-to-Ethernet Adaptation Layer
                   |
                   v
 +---------------------+-------------+---------+
 | Ethernet II Header  | IPv6 Header | Payload |
 +---------------------+-------------+---------+






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   The Receiver and Transmitter Address fields in the 802.11 Data Header
   contain the same values as the Destination and the Source Address
   fields in the Ethernet II Header, respectively.  The value of the
   Type field in the LLC Header is the same as the value of the Type
   field in the Ethernet II Header.

   The ".11 Trailer" contains solely a 4-byte Frame Check Sequence.

   The Ethernet Adaptation Layer performs operations in relation to IP
   fragmentation and MTU.  One of these operations is briefly described
   in section Section 5.1.

   In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11
   Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in
   the following figure:


+--------------------+-------------+-------------+---------+-----------+
| 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------+-----------+

or

+--------------------+-------------+-------------+---------+-----------+
| 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------+-----------+


   The distinction between the two formats is given by the value of the
   field "Type/Subtype".  The value of the field "Type/Subtype" in the
   802.11 Data header is 0x0020.  The value of the field "Type/Subtype"
   in the 802.11 QoS header is 0x0028.

   The mapping between qos-related fields in the IPv6 header (e.g.
   "Traffic Class", "Flow label") and fields in the "802.11 QoS Data
   Header" (e.g.  "QoS Control") are not specified in this document.
   Guidance for a potential mapping is provided in
   [I-D.ietf-tsvwg-ieee-802-11], although it is not specific =
to OCB
   mode.









[Sri] The applicability of the QoS mapping draft to =
802.11-OCB needs further investigation, IMO.











5.3.  Link-Local =
Addresses


   The link-local address of an 802.11-OCB interface is formed in the
   same manner as on an Ethernet interface.  This manner is described in
   section 5 of [RFC2464].





[Sri] Does this go against the =
8064 recommendation on Interface identifier =
generation?
May be RFC7217 =
for interface identifier generation in conjunction with the link-local =
address generation per RFC2464





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5.4.  Address =
Mapping


   For unicast as for multicast, there is no change from the unicast and
   multicast address mapping format of Ethernet interfaces, as defined
   by sections 6 and 7 of [RFC2464].









[Sri] RFC6085 =
specified mapping is also relevant; If the communication peers are aware =
that there is only one peer, it should apply 6085 specified mapping. =
That mode is relevant for 802.11-OCB types links as well.








5.4.1.  Address =
Mapping -- Unicast


   The procedure for mapping IPv6 unicast addresses into Ethernet link-
   layer addresses is described in [RFC4861].  The =
Source/Target Link-
   layer Address option has the following form when the link-layer is
   Ethernet.



[Sri] I thought, mapping of IPv6 unicast addresses to =
Ethernet link-layer addresses is specified in section 6, of RFC2464 and =
not in RFC4861.











  =
                    0                   1
                      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |     Type      |    Length     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |                               |
                     +-          Ethernet           -+
                     |                               |
                     +-           Address           -+
                     |                               |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Option fields:

   Type
      1 for Source Link-layer address.
      2 for Target Link-layer address.

   Length
      1 (in units of 8 octets).

   Ethernet Address
      The 48 bit Ethernet IEEE 802 address, in canonical bit order.


5.4.2.  Address =
Mapping -- Multicast


   IPv6 protocols often make use of IPv6 multicast addresses in the
   destination field of IPv6 headers.  For example, an ICMPv6 link-
   scoped Neighbor Advertisement is sent to the IPv6 address ff02::1
   denoted "all-nodes" address.  When transmitting these packets on
   802.11-OCB links it is necessary to map the IPv6 address to a MAC
   address.




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   The same mapping requirement applies to the link-scoped multicast
   addresses of other IPv6 protocols as well.  In DHCPv6, the
   "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF the
   "All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped
   on a multicast MAC address.

   An IPv6 packet with a multicast destination address DST, consisting
   of the sixteen octets DST[1] through DST[16], is transmitted to the
   IEEE 802.11-OCB MAC multicast address whose first two octets are the
   value 0x3333 and whose last four octets are the last four octets of
   DST.



[Sri] Please add a reference to =
Section 7, RFC4861 and also RFC6085. In general, for both unicast and =
multicast, you may want to clearly say that this is per the existing =
specs and duplicated here for convenience. 





  =
                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |   DST[13]     |   DST[14]     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |   DST[15]     |   DST[16]     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   A Group ID TBD of length 112bits may be requested from IANA; this
   Group ID signifies "All 80211OCB Interfaces Address".  Only the least
   32 significant bits of this "All 80211OCB Interfaces Address" will be
   mapped to and from a MAC multicast address.

   Transmitting IPv6 packets to multicast destinations over 802.11 links
   proved to have some performance issues
   [I-D.perkins-intarea-multicast-ieee802].  These issues may =
be
   exacerbated in OCB mode.  Solutions for these problems should
   consider the OCB mode of operation.


5.5.  Stateless =
Autoconfiguration


   The Interface Identifier for an 802.11-OCB interface is formed using
   the same rules as the Interface Identifier for an Ethernet interface;
   this is described in section 4 of [RFC2464].  No changes are needed,
   but some care must be taken when considering the use of the SLAAC
   procedure.








[Sri] Per my earlier comment, please refer to the current =
recommendation on interface-identifier generation and its use in =
link-local, global or other addresses.


   The bits in the the interface identifier have no generic meaning and
   the identifier should be treated as an opaque value.  The bits
   'Universal' and 'Group' in the identifier of an 802.11-OCB interface
   are significant, as this is an IEEE link-layer address.  The details
   of this significance are described in [I-D.ietf-6man-ug].





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   As with all Ethernet and 802.11 interface identifiers ([RFC7721]),
   the identifier of an 802.11-OCB interface may involve privacy risks.
   A vehicle embarking an On-Board Unit whose egress interface is
   802.11-OCB may expose itself to eavesdropping and subsequent
   correlation of data; this may reveal data considered private by the
   vehicle owner; there is a risk of being tracked; see the privacy
   considerations described in Appendix C.






[Sri] I think there are other =
security issues here; the absence of link-layer security opens up =
Mac-spoofing and IP address hijacking.  That should be =
mentioned.






  =
 If stable Interface Identifiers are needed in order to form IPv6
   addresses on 802.11-OCB links, it is recommended to follow the
   recommendation in [I-D.ietf-6man-default-iids].


5.6.  Subnet =
Structure


   The 802.11 networks in OCB mode may be considered as 'ad-hoc'
   networks.  The addressing model for such networks is described in
   [RFC5889].






[Sri] Per my earlier comment, there is no system level view =
of the network where 802.11-OCB links are used. So, in the absence of =
such discussion So, I am not sure =
what part of RFC5889 is applicable here. For example, =
link-local addresses may just work =
fine. 








6.  Example IPv6 =
Packet captured over a IEEE 802.11-OCB link


   We remind that a main goal of this document is to make the case that
   IPv6 works fine over 802.11-OCB networks.  Consequently, this section
   is an illustration of this concept and thus can help the implementer
   when it comes to running IPv6 over IEEE 802.11-OCB.  By way of
   example we show that there is no modification in the headers when
   transmitted over 802.11-OCB networks - they are transmitted like any
   other 802.11 and Ethernet packets.

   We describe an experiment of capturing an IPv6 packet on an
   802.11-OCB link.  In this experiment, the packet is an IPv6 Router
   Advertisement.  This packet is emitted by a Router on its 802.11-OCB
   interface.  The packet is captured on the Host, using a network
   protocol analyzer (e.g.  Wireshark); the capture is performed in two
   different modes: direct mode and 'monitor' mode.  The topology used
   during the capture is depicted below.


              +--------+                                +-------+
              |        |        802.11-OCB Link         |       |
           ---| Router |--------------------------------| Host  |
              |        |                                |       |
              +--------+                                +-------+


   During several capture operations running from a few moments to
   several hours, no message relevant to the BSSID contexts were
   captured (no Association Request/Response, Authentication Req/Resp,




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   Beacon).  This shows that the operation of 802.11-OCB is outside the
   context of a BSSID.

   Overall, the captured message is identical with a capture of an IPv6
   packet emitted on a 802.11b interface.  The contents are precisely
   similar.






[Sri] I suggest moving this discussion under the section =
=E2=80=9CImplementation Status=E2=80=9D, which will eventually be =
removed from the RFC. There is nothing new here. This are details on =
experimentation. But, if you think there is some useful information  =
such as discussion on Capture mode ..etc, you may want to move this =
entire section to Appendix. Implementors may use these tools for =
verification.











6.1.  Capture in =
Monitor Mode


   The IPv6 RA packet captured in monitor mode is illustrated below.
   The radio tap header provides more flexibility for reporting the
   characteristics of frames.  The Radiotap Header is prepended by this
   particular stack and operating system on the Host machine to the RA
   packet received from the network (the Radiotap Header is not present
   on the air).  The implementation-dependent Radiotap Header is useful
   for piggybacking PHY information from the chip's registers as data in
   a packet understandable by userland applications using Socket
   interfaces (the PHY interface can be, for example: power levels, data
   rate, ratio of signal to noise).

   The packet present on the air is formed by IEEE 802.11 Data Header,
   Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.



     Radiotap Header v0
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Header Revision|  Header Pad   |    Header length              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Present flags                         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Data Rate     |             Pad                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IEEE 802.11 Data Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Type/Subtype and Frame Ctrl  |          Duration             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Receiver Address...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Receiver Address           |      Transmitter Address...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Transmitter Address                                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                            BSS Id...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... BSS Id                     |  Frag Number and Seq Number   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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     Logical-Link Control Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |      DSAP   |I|     SSAP    |C| Control field | Org. code...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Organizational Code        |             Type              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                         Source Address                        +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                      Destination Address                      +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+-


   The value of the Data Rate field in the Radiotap header is set to 6
   Mb/s.  This indicates the rate at which this RA was received.





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   The value of the Transmitter address in the IEEE 802.11 Data Header
   is set to a 48bit value.  The value of the destination address is
   33:33:00:00:00:1 (all-nodes multicast address).  The value of the BSS
   Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network
   protocol analyzer as being "broadcast".  The Fragment number and
   sequence number fields are together set to 0x90C6.

   The value of the Organization Code field in the Logical-Link Control
   Header is set to 0x0, recognized as "Encapsulated Ethernet".  The
   value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise
   #86DD), recognized as "IPv6".

   A Router Advertisement is periodically sent by the router to
   multicast group address ff02::1.  It is an icmp packet type 134.  The
   IPv6 Neighbor Discovery's Router Advertisement message contains an
   8-bit field reserved for single-bit flags, as described in [RFC4861].

   The IPv6 header contains the link local address of the router
   (source) configured via EUI-64 algorithm, and destination address set
   to ff02::1.  Recent versions of network protocol analyzers (e.g.
   Wireshark) provide additional informations for an IP address, if a
   geolocalization database is present.  In this example, the
   geolocalization database is absent, and the "GeoIP" information is
   set to unknown for both source and destination addresses (although
   the IPv6 source and destination addresses are set to useful values).
   This "GeoIP" can be a useful information to look up the city,
   country, AS number, and other information for an IP address.





[Sri] Not sure, why all of this =
text should be in the specification. 





  =
 The Ethernet Type field in the logical-link control header is set to
   0x86dd which indicates that the frame transports an IPv6 packet.  In
   the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
   which is he corresponding multicast MAC address.  The BSS id is a
   broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link
   duration between vehicles and the roadside infrastructure, there is
   no need in IEEE 802.11-OCB to wait for the completion of association
   and authentication procedures before exchanging data.  IEEE
   802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)
   and may start communicating as soon as they arrive on the
   communication channel.


6.2.  Capture in =
Normal Mode


   The same IPv6 Router Advertisement packet described above (monitor
   mode) is captured on the Host, in the Normal mode, and depicted
   below.






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     Ethernet II Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Destination...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ...Destination                 |           Source...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ...Source                                                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |          Type                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                         Source Address                        +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                      Destination Address                      +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+-





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   One notices that the Radiotap Header is not prepended, and that the
   IEEE 802.11 Data Header and the Logical-Link Control Headers are not
   present.  On another hand, a new header named Ethernet II Header is
   present.

   The Destination and Source addresses in the Ethernet II header
   contain the same values as the fields Receiver Address and
   Transmitter Address present in the IEEE 802.11 Data Header in the
   "monitor" mode capture.

   The value of the Type field in the Ethernet II header is 0x86DD
   (recognized as "IPv6"); this value is the same value as the value of
   the field Type in the Logical-Link Control Header in the "monitor"
   mode capture.

   The knowledgeable experimenter will no doubt notice the similarity of
   this Ethernet II Header with a capture in normal mode on a pure
   Ethernet cable interface.

   It may be interpreted that an Adaptation layer is inserted in a pure
   IEEE 802.11 MAC packets in the air, before delivering to the
   applications.  In detail, this adaptation layer may consist in
   elimination of the Radiotap, 802.11 and LLC headers and insertion of
   the Ethernet II header.  In this way, it can be stated that IPv6 runs
   naturally straight over LLC over the 802.11-OCB MAC layer, as shown
   by the use of the Type 0x86DD, and assuming an adaptation layer
   (adapting 802.11 LLC/MAC to Ethernet II header).


7.  Security =
Considerations


   Any security mechanism at the IP layer or above that may be carried
   out for the general case of IPv6 may also be carried out for IPv6
   operating over 802.11-OCB.






  =
 802.11-OCB does not provide any cryptographic protection, because it
   operates outside the context of a BSS (no Association Request/
   Response, no Challenge messages).  Any attacker can therefore just
   sit in the near range of vehicles, sniff the network (just set the
   interface card's frequency to the proper range) and perform attacks
   without needing to physically break any wall.  Such a link is way
   less protected than commonly used links (wired link or protected
   802.11).



[Sri] Per my earlier comment, =
there is more than one attack vector possible
1.) Absence of link-layer security and the potential for mac =
address spoofing 
2.) IP address / Session hijacking 
3.) Data privacy per your =
text






  =
 At the IP layer, IPsec can be used to protect unicast communications,
   and SeND can be used for multicast communications. 





[Sri] IPSec can be used for =
protecting both multicast or unicast communication; RFC-5374 with =
GDOI.











 =
If no protection
   is used by the IP layer, upper layers should be protected.
   Otherwise, the end-user or system should be warned about the risks
   they run.



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   As with all Ethernet and 802.11 interface identifiers, there may
   exist privacy risks in the use of 802.11-OCB interface identifiers.
   Moreover, in outdoors vehicular settings, the privacy risks are more
   important than in indoors settings.  New risks are induced by the
   possibility of attacker sniffers deployed along routes which listen
   for IP packets of vehicles passing by.  For this reason, in the
   802.11-OCB deployments, there is a strong necessity to use protection
   tools such as dynamically changing MAC addresses.  This may help
   mitigate privacy risks to a certain level.  On another hand, it may
   have an impact in the way typical IPv6 address auto-configuration is
   performed for vehicles (SLAAC would rely on MAC addresses amd would
   hence dynamically change the affected IP address), in the way the
   IPv6 Privacy addresses were used, and other effects.


8.  IANA =
Considerations



9.  =
Contributors


   Romain Kuntz contributed extensively about IPv6 handovers between
   links running outside the context of a BSS (802.11-OCB links).

   Tim Leinmueller contributed the idea of the use of IPv6 over
   802.11-OCB for distribution of certificates.

   Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey
   Voronov provided significant feedback on the experience of using IP
   messages over 802.11-OCB in initial trials.

   Michelle Wetterwald contributed extensively the MTU discussion,
   offered the ETSI ITS perspective, and reviewed other parts of the
   document.


10.  =
Acknowledgements


   The authors would like to thank Witold Klaudel, Ryuji Wakikawa,
   Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan
   Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray
   Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,
   Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,
   Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,
   Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and
   William Whyte.  Their valuable comments clarified certain issues and
   generally helped to improve the document.

   Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB
   drivers for linux and described how.





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   For the multicast discussion, the authors would like to thank Owen
   DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and
   participants to discussions in network working groups.

   The authours would like to thank participants to the Birds-of-
   a-Feather "Intelligent Transportation Systems" meetings held at IETF
   in 2016.


11.  =
References



11.1.  Normative =
References


   [I-D.ietf-6man-default-iids]
              Gont, F., Cooper, A., Thaler, D., and S. LIU,
              "Recommendation on Stable IPv6 Interface Identifiers",
              draft-ietf-6man-default-iids-16 (work in progress),
              September 2016.

   [I-D.ietf-6man-ug]
              Carpenter, B. and S. Jiang, "Significance of IPv6
              Interface Identifiers", draft-ietf-6man-ug-06 (work in
              progress), December 2013.

   [I-D.ietf-tsvwg-ieee-802-11]
              Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE
              802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-06 (work in
              progress), August 2017.

   [RFC1042]  =
Postel, J. and J. Reynolds, "Standard for the transmission
              of IP datagrams over IEEE 802 networks", STD 43, RFC 1042,
              DOI 10.17487/RFC1042, February 1988, <https://www.rfc-
              editor.org/info/rfc1042>.

   [RFC2119]  =
Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997, <https://www.rfc-
              editor.org/info/rfc2119>.

   [RFC2460]  =
Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, =
DOI 10.17487/RFC2460,
              December 1998, <https://www.rfc-editor.org/info/rfc2460>.

   [RFC2464]  =
Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998,
              <https://www.rfc-editor.org/info/rfc2464>.






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   [RFC3963]  =
Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol",
              RFC 3963, DOI 10.17487/RFC3963, January 2005,
              <https://www.rfc-editor.org/info/rfc3963>.

   [RFC4086]  =
Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security", BCP 106, RFC 4086,
              DOI 10.17487/RFC4086, June 2005, <https://www.rfc-
              editor.org/info/rfc4086>.

   [RFC4301]  =
Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, =
DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.

   [RFC4429]  =
Moore, N., "Optimistic Duplicate Address Detection (DAD)
              for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006,
              <https://www.rfc-editor.org/info/rfc4429>.

   [RFC4861]  =
Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007, <https://www.rfc-
              editor.org/info/rfc4861>.

   [RFC5889]  =
Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing
              Model in Ad Hoc Networks", RFC 5889, =
DOI 10.17487/RFC5889,
              September 2010, <https://www.rfc-editor.org/info/rfc5889>.

   [RFC6275]  =
Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", RFC 6275, =
DOI 10.17487/RFC6275, July
              2011, <https://www.rfc-editor.org/info/rfc6275>.

   [RFC6775]  =
Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
              Bormann, "Neighbor Discovery Optimization for IPv6 over
              Low-Power Wireless Personal Area Networks (6LoWPANs)",
              RFC 6775, DOI 10.17487/RFC6775, November 2012,
              <https://www.rfc-editor.org/info/rfc6775>.

   [RFC7721]  =
Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
              Considerations for IPv6 Address Generation Mechanisms",
              RFC 7721, DOI 10.17487/RFC7721, March 2016,
              <https://www.rfc-editor.org/info/rfc7721>.


11.2.  Informative =
References









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   [fcc-cc]   =
"'Report and Order, Before the Federal Communications
              Commission Washington, D.C. 20554', FCC 03-324, Released
              on February 10, 2004, document FCC-03-324A1.pdf, document
              freely available at URL
              http://www.its.dot.gov/exit/fcc_edocs.htm downloaded on
              October 17th, 2013.".

   [fcc-cc-172-184]
              "'Memorandum Opinion and Order, Before the Federal
              Communications Commission Washington, D.C. 20554', FCC
              06-10, Released on July 26, 2006, document FCC-
              06-110A1.pdf, document freely available at URL
              http://hraunfoss.fcc.gov/edocs_public/attachmatch/
              FCC-06-110A1.pdf downloaded on June 5th, 2014.".

   [I-D.jeong-ipwave-vehicular-networking-survey]
              Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M.
              Wetterwald, "Survey on IP-based Vehicular Networking for
              Intelligent Transportation Systems", draft-jeong-ipwave-
              vehicular-networking-survey-03 (work in =
progress), June
              2017.

   [I-D.perkins-intarea-multicast-ieee802]
              Perkins, C., Stanley, D., Kumari, W., and J. Zuniga,
              "Multicast Considerations over IEEE 802 Wireless Media",
              draft-perkins-intarea-multicast-ieee802-03 (work in
              progress), July 2017.

   [I-D.petrescu-its-scenarios-reqs]
              Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel,
              "Scenarios and Requirements for IP in Intelligent
              Transportation Systems", draft-petrescu-its-scenarios-
              reqs-03 (work in progress), October 2013.

   [ieee1609.2]
              "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Security Services for
              Applications and Management Messages.  Example URL
              http://ieeexplore.ieee.org/document/7426684/ accessed on
              August 17th, 2017.".

   [ieee1609.3]
              "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Networking Services.
              Example URL http://ieeexplore.ieee.org/document/7458115/
              accessed on August 17th, 2017.".





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   [ieee1609.4]
              "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Multi-Channel
              Operation.  Example URL
              http://ieeexplore.ieee.org/document/7435228/ accessed on
              August 17th, 2017.".

   [ieee802.11-2012]
              "802.11-2012 - IEEE Standard for Information technology--
              Telecommunications and information exchange between
              systems Local and metropolitan area networks--Specific
              requirements Part 11: Wireless LAN Medium Access Control
              (MAC) and Physical Layer (PHY) Specifications.  Downloaded
              on October 17th, 2013, from IEEE Standards, document
              freely available at URL
              http://standards.ieee.org/findstds/
              standard/802.11-2012.html retrieved on October 17th,
              2013.".

   [ieee802.11p-2010]
              "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information
              Technology - Telecommunications and information exchange
              between systems - Local and metropolitan area networks -
              Specific requirements, Part 11: Wireless LAN Medium Access
              Control (MAC) and Physical Layer (PHY) Specifications,
              Amendment 6: Wireless Access in Vehicular Environments;
              document freely available at URL
              http://standards.ieee.org/getieee802/
              download/802.11p-2010.pdf retrieved on September 20th,
              2013.".


Appendix A.  =
ChangeLog


   The changes are listed in reverse chronological order, most recent
   changes appearing at the top of the list.

   =46rom draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave-
   ipv6-over-80211ocb-04

   o  Removed a few informative references pointing to Dx draft IEEE
      1609 documents.

   o  Removed outdated informative references to ETSI documents.

   o  Added citations to IEEE 1609.2, .3 and .4-2016.

   o  Minor textual issues.




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   =46rom draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave-
   ipv6-over-80211ocb-03

   o  Keep the previous text on multiple addresses, so remove talk about
      MIP6, NEMOv6 and MCoA.

   o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.

   o  Clarified the figure showing Infrastructure mode and OCB mode side
      by side.

   o  Added a reference to the IP Security Architecture RFC.

   o  Detailed the IPv6-per-channel prohibition paragraph which reflects
      the discussion at the last IETF IPWAVE WG meeting.

   o  Added section "Address Mapping -- Unicast".

   o  Added the ".11 Trailer" to pictures of 802.11 frames.

   o  Added text about SNAP carrying the Ethertype.

   o  New RSU definition allowing for it be both a Router and not
      necessarily a Router some times.

   o  Minor textual issues.

   =46rom draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave-
   ipv6-over-80211ocb-02

   o  Replaced almost all occurences of 802.11p with 802.11-OCB, leaving
      only when explanation of evolution was necessary.

   o  Shortened by removing parameter details from a paragraph in the
      Introduction.

   o  Moved a reference from Normative to Informative.

   o  Added text in intro clarifying there is no handover spec at IEEE,
      and that 1609.2 does provide security services.

   o  Named the contents the fields of the EthernetII header (including
      the Ethertype bitstring).

   o  Improved relationship between two paragraphs describing the
      increase of the Sequence Number in 802.11 header upon IP
      fragmentation.




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   o  Added brief clarification of "tracking".

   =46rom draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave-
   ipv6-over-80211ocb-01

   o  Introduced message exchange diagram illustrating differences
      between 802.11 and 802.11 in OCB mode.

   o  Introduced an appendix listing for information the set of 802.11
      messages that may be transmitted in OCB mode.

   o  Removed appendix sections "Privacy Requirements", "Authentication
      Requirements" and "Security Certificate Generation".

   o  Removed appendix section "Non IP Communications".

   o  Introductory phrase in the Security Considerations section.

   o  Improved the definition of "OCB".

   o  Introduced theoretical stacked layers about IPv6 and IEEE layers
      including EPD.

   o  Removed the appendix describing the details of prohibiting IPv6 on
      certain channels relevant to 802.11-OCB.

   o  Added a brief reference in the privacy text about a precise clause
      in IEEE 1609.3 and .4.

   o  Clarified the definition of a Road Side Unit.

   o  Removed the discussion about security of WSA (because is non-IP).

   o  Removed mentioning of the GeoNetworking discussion.

   o  Moved references to scientific articles to a separate 'overview'
      draft, and referred to it.


Appendix B.  Changes =
Needed on a software driver 802.11a to become a

             802.11-OCB driver

   The 802.11p amendment modifies both the 802.11 stack's physical and
   MAC layers but all the induced modifications can be quite easily
   obtained by modifying an existing 802.11a ad-hoc stack.

   Conditions for a 802.11a hardware to be 802.11-OCB compliant:





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   o  The chip must support the frequency bands on which the regulator
      recommends the use of ITS communications, for example using IEEE
      802.11-OCB layer, in France: 5875MHz to 5925MHz.

   o  The chip must support the half-rate mode (the internal clock
      should be able to be divided by two).

   o  The chip transmit spectrum mask must be compliant to the "Transmit
      spectrum mask" from the IEEE 802.11p amendment (but experimental
      environments tolerate otherwise).

   o  The chip should be able to transmit up to 44.8 dBm when used by
      the US government in the United States, and up to 33 dBm in
      Europe; other regional conditions apply.

   Changes needed on the network stack in OCB mode:

   o  Physical layer:

      *  The chip must use the Orthogonal Frequency Multiple Access
         (OFDM) encoding mode.

      *  The chip must be set in half-mode rate mode (the internal clock
         frequency is divided by two).

      *  The chip must use dedicated channels and should allow the use
         of higher emission powers.  This may require modifications to
         the regulatory domains rules, if used by the kernel to enforce
         local specific restrictions.  Such modifications must respect
         the location-specific laws.

      MAC layer:

      *  All management frames (beacons, join, leave, and others)
         emission and reception must be disabled except for frames of
         subtype Action and Timing Advertisement (defined below).

      *  No encryption key or method must be used.

      *  Packet emission and reception must be performed as in ad-hoc
         mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).

      *  The functions related to joining a BSS (Association Request/
         Response) and for authentication (Authentication Request/Reply,
         Challenge) are not called.

      *  The beacon interval is always set to 0 (zero).




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      *  Timing Advertisement frames, defined in the amendment, should
         be supported.  The upper layer should be able to trigger such
         frames emission and to retrieve information contained in
         received Timing Advertisements.


Appendix C.  Design =
Considerations


   The networks defined by 802.11-OCB are in many ways similar to other
   networks of the 802.11 family.  In theory, the encapsulation of IPv6
   over 802.11-OCB could be very similar to the operation of IPv6 over
   other networks of the 802.11 family.  However, the high mobility,
   strong link asymetry and very short connection makes the 802.11-OCB
   link significantly different from other 802.11 networks.  Also, the
   automotive applications have specific requirements for reliability,
   security and privacy, which further add to the particularity of the
   802.11-OCB link.


C.1.  Vehicle =
ID


   Automotive networks require the unique representation of each of
   their node.  Accordingly, a vehicle must be identified by at least
   one unique identifier.  The current specification at ETSI and at IEEE
   1609 identifies a vehicle by its MAC address uniquely obtained from
   the 802.11-OCB NIC.

   A MAC address uniquely obtained from a IEEE 802.11-OCB NIC
   implicitely generates multiple vehicle IDs in case of multiple
   802.11-OCB NICs.  A mechanims to uniquely identify a vehicle
   irrespectively to the different NICs and/or technologies is required.


C.2.  Reliability =
Requirements


   The dynamically changing topology, short connectivity, mobile
   transmitter and receivers, different antenna heights, and many-to-
   many communication types, make IEEE 802.11-OCB links significantly
   different from other IEEE 802.11 links.  Any IPv6 mechanism operating
   on IEEE 802.11-OCB link MUST support strong link asymetry, spatio-
   temporal link quality, fast address resolution and transmission.

   IEEE 802.11-OCB strongly differs from other 802.11 systems to operate
   outside of the context of a Basic Service Set.  This means in
   practice that IEEE 802.11-OCB does not rely on a Base Station for all
   Basic Service Set management.  In particular, IEEE 802.11-OCB SHALL
   NOT use beacons.  Any IPv6 mechanism requiring L2 services from IEEE
   802.11 beacons MUST support an alternative service.






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   Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
   implement a mechanism for transmitter and receiver to converge to a
   common channel.

   Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST
   implement an distributed mechanism to authenticate transmitters and
   receivers without the support of a DHCP server.

   Time synchronization not being available, IPv6 over IEEE 802.11-OCB
   MUST implement a higher layer mechanism for time synchronization
   between transmitters and receivers without the support of a NTP
   server.

   The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB
   MUST disable management mechanisms requesting acknowledgements or
   replies.

   The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE
   802.11-OCB MUST implement fast IPv6 mobility management mechanisms.


C.3.  Multiple =
interfaces


   There are considerations for 2 or more IEEE 802.11-OCB interface
   cards per vehicle.  For each vehicle taking part in road traffic, one
   IEEE 802.11-OCB interface card could be fully allocated for Non IP
   safety-critical communication.  Any other IEEE 802.11-OCB may be used
   for other type of traffic.

   The mode of operation of these other wireless interfaces is not
   clearly defined yet.  One possibility is to consider each card as an
   independent network interface, with a specific MAC Address and a set
   of IPv6 addresses.  Another possibility is to consider the set of
   these wireless interfaces as a single network interface (not
   including the IEEE 802.11-OCB interface used by Non IP safety
   critical communications).  This will require specific logic to
   ensure, for example, that packets meant for a vehicle in front are
   actually sent by the radio in the front, or that multiple copies of
   the same packet received by multiple interfaces are treated as a
   single packet.  Treating each wireless interface as a separate
   network interface pushes such issues to the application layer.

   The privacy requirements of [] imply that if these multiple
   interfaces are represented by many network interface, a single
   renumbering event SHALL cause renumbering of all these interfaces.
   If one MAC changed and another stayed constant, external observers
   would be able to correlate old and new values, and the privacy
   benefits of randomization would be lost.




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   The privacy requirements of Non IP safety-critical communications
   imply that if a change of pseudonyme occurs, renumbering of all other
   interfaces SHALL also occur.


C.4.  MAC Address =
Generation


   When designing the IPv6 over 802.11-OCB address mapping, we will
   assume that the MAC Addresses will change during well defined
   "renumbering events".  The 48 bits randomized MAC addresses will have
   the following characteristics:

   o  Bit "Local/Global" set to "locally admninistered".

   o  Bit "Unicast/Multicast" set to "Unicast".

   o  46 remaining bits set to a random value, using a random number
      generator that meets the requirements of [RFC4086].

   The way to meet the randomization requirements is to retain 46 bits
   from the output of a strong hash function, such as SHA256, taking as
   input a 256 bit local secret, the "nominal" MAC Address of the
   interface, and a representation of the date and time of the
   renumbering event.


Appendix D.  IEEE =
802.11 Messages Transmitted in OCB mode


   For information, at the time of writing, this is the list of IEEE
   802.11 messages that may be transmitted in OCB mode, i.e. when
   dot11OCBActivated is true in a STA:

   o  The STA may send management frames of subtype Action and, if the
      STA maintains a TSF Timer, subtype Timing Advertisement;

   o  The STA may send control frames, except those of subtype PS-Poll,
      CF-End, and CF-End plus CFAck;

   o  The STA may send data frames of subtype Data, Null, QoS Data, and
      QoS Null.

Authors' Addresses








_______________________________________________
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mailing list
its@ietf.org
https://www.ietf.org/mailman/listinfo/its

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From: "Sri Gundavelli (sgundave)" 
To: Russ Housley 
CC: "its@ietf.org" 
Thread-Topic: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
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Agree!

If we look at this work as strictly about transmitting an IPv6 on particula=
r type of link, then its just about defining the mapping of IPv6 address to=
 link-layer addresses, and about details on L2 header construction ..etc; m=
ore along the lines of RFC2464 / 6085 ..etc.  We don=92t talk about the ope=
rating environment, ND, security, routing ..we only present the relation be=
tween L2 and L3 header fields and stay silent on all other aspects.

But, the issue is when we bring the system level aspects, then we may have =
to state the assumptions as the considerations change based on those assump=
tions. For example, if the operating environment is about dynamically movin=
g IPv6 nodes (connected over 802.11-OCB links), which come into proximity f=
or a transient period of time, then we don=92t know which prefix is routabl=
e from which 802.11-OCB peer. How does routing/ND work? This is more a MANE=
T problem.  Similarly, for other operating environments, there may be diffe=
rent set of security, ND, routing and other considerations.

The document has to state those assumptions and then present the solution.


Sri







From: Russ Housley >
Date: Monday, August 28, 2017 at 7:06 AM
To: Sri Gundavelli >
Cc: "its@ietf.org" >
Subject: Re: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211o=
cb-04.txt

Thanks very much.  These questions make me wonder whether there are differe=
nt answers depending on motion.  If the vehicle is parked, a different set =
of solutions might be desirable.

Russ


On Aug 27, 2017, at 11:00 PM, Sri Gundavelli (sgundave) > wrote:


Attached is my review feedback.

In general there is lot of good information in the document. But, there are=
 also few areas where additional clarifications will greatly help.

1.) Its not clear, if the document makes any assumption on the operating en=
vironment/communication profile. There is not much discussion on that aspec=
t; For example, Is it always a one-hop communication between RSU and OBU wh=
ere the 802.11-OCB link?  So, is the use of IPv6 only in that context of 1-=
hop communication?

2.) There is also no discussion on how these links get formed in vehicular =
environment and when they are attached/detached.

3.) How do nodes discover each other?  How does ND resolution work? Are the=
se messages received by a multiple RSU=92s, or a single RSU? Whats the impl=
ication of that. Note that you don=92t have that issue in 802.11, given the=
 association to an access point, which in turn maps the links to a VLAN/sub=
net.

4.) What happens as a vehicle moves between RSU=92s, how does it impact add=
ress configuration?   Is DHCPv6 based address configuration relevant here?


 Please see inline for additional comments.




------------------------------------------------------------------


Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside


the Context of a Basic Service Set (IPv6-over-80211ocb)


draft-ietf-ipwave-ipv6-over-80211ocb-04.txt



[Sri] May be change to, =93..in mode .." =97> =93..operating in mode ..=94 =
 ?



Abstract

   In order to transmit IPv6 packets on IEEE 802.11 networks run outside
   the context of a basic service set (OCB, earlier "802.11p") there is
   a need to define a few parameters such as the recommended Maximum
   Transmission Unit size, the header format preceding the IPv6 header,
   the Type value within it, and others.  This document describes these
   parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
   layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
   Ethernet layers - by using an Ethernet Adaptation Layer.


[Sri] Is it =93recommended MTU size", or "supported MTU size on the 802.11 =
OCB link?



   In addition, the document attempts to list what is different in
   802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
   layers, layers over which IPv6 protocols operates without issues.
   Most notably, the operation outside the context of a BSS (OCB) has
   impact on IPv6 handover behaviour and on IPv6 security.


[Sri] Minor comment. May be instead of using the =93layer=94 terminology, y=
ou may want to present this as IPv6 support on "802.11 OCB" links.


   An example of an IPv6 packet captured while transmitted over an IEEE
   802.11 OCB link (802.11p) is given.


[Sri] Last paragraph can be ommitted in my view. That=92s too much of detai=
l for Abstract.


Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute



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   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 18, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 an=
d the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   =
3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   =
5
   3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    6
   4.  Aspects introduced by the OCB mode to 802.11  . . . . . . . .   =
6
   5.  Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . .  1=
0
     5.1.  Maximum Transmission Unit (MTU) . . . . . . . . . . . . . =
 10
     5.2.  Frame Format  . . . . . . . . . . . . . . . . . . . . . . =
 11
       5.2.1.  Ethernet Adaptation Layer . . . . . . . . . . . . . =
.  12
     5.3.  Link-Local Addresses  . . . . . . . . . . . . . . . . . . =
 13
     5.4.  Address Mapping . . . . . . . . . . . . . . . . . . . . . =
 14
       5.4.1.  Address Mapping -- Unicast  . . . . . . . . . . . . =
.  14
       5.4.2.  Address Mapping -- Multicast  . . . . . . . . . . . =
.  14
     5.5.  Stateless Autoconfiguration . . . . . . . . . . . . . . . =
 15
     5.6.  Subnet Structure  . . . . . . . . . . . . . . . . . . . . =
 16
   6.  Example IPv6 Packet captured over a IEEE 802.11-OCB link  . .  1=
6
     6.1.  Capture in Monitor Mode . . . . . . . . . . . . . . . . . =
 17
     6.2.  Capture in Normal Mode  . . . . . . . . . . . . . . . . . =
 19
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  2=
1
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  2=
2
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  2=
2
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  =
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   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  =
23
     11.1.  Normative References . . . . . . . . . . . . . . . . . .=
  23
     11.2.  Informative References . . . . . . . . . . . . . . . . .=
  24
   Appendix A.  ChangeLog  . . . . . . . . . . . . . . . . . . . . .  =
26
   Appendix B.  Changes Needed on a software driver 802.11a to
                become a                     802.11-OCB driver . . .  28
   Appendix C.  Design Considerations  . . . . . . . . . . . . . . .  =
30
     C.1.  Vehicle ID  . . . . . . . . . . . . . . . . . . . . . . .=
  30
     C.2.  Reliability Requirements  . . . . . . . . . . . . . . . .=
  30
     C.3.  Multiple interfaces . . . . . . . . . . . . . . . . . . .=
  31
     C.4.  MAC Address Generation  . . . . . . . . . . . . . . . . .=
  32
   Appendix D.  IEEE 802.11 Messages Transmitted in OCB mode . . . .  =
32
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  32
1.  Introduction


   This document describes the transmission of IPv6 packets on IEEE Std
   802.11 OCB networks (earlier known as 802.11p).


[Sri] Please add a reference to the IEEE specification that defines the OCB=
 mode.



This involves the
   layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with
   an LLC layer).  Compared to running IPv6 over the Ethernet MAC layer,
   there is no modification required to the standards: IPv6 works fine
   directly over 802.11 OCB too (with an LLC layer).

   The term "802.11p" is an earlier definition.  As of year 2012, the
   behaviour of "802.11p" networks has been rolled in the document IEEE
   Std 802.11-2012.  In this document the term 802.11p disappears.
   Instead, each 802.11p feature is conditioned by a flag in the
   Management Information Base.  That flag is named "OCBActivated".
   Whenever OCBActivated is set to true the feature it relates to
   represents an earlier 802.11p feature.  For example, an 802.11
   STAtion operating outside the context of a basic service set has the
   OCBActivated flag set.  Such a station, when it has the flag set, it
   uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.

   In the following text we use the term "802.11p" to mean 802.11-2012
   OCB.

   The IPv6 network layer operates on 802.11 OCB in the same manner as
   it operates on 802.11 WiFi, with a few particular exceptions.  The
   IPv6 network layer operates on WiFi by involving an Ethernet
   Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers
   to Ethernet II headers.  The operation of IP on Ethernet is described
   in [RFC1042] and [RFC2464].  The situation of IPv6 networking layer
   on Ethernet Adaptation Layer is illustrated below:







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                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |                 IPv6                  |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |       Ethernet Adaptation Layer       |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi MAC           |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi PHY           |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   (in the above figure, a WiFi profile is represented; this is used
   also for OCB profile.)

   A more theoretical and detailed view of layer stacking, and
   interfaces between the IP layer and 802.11 OCB layers, is illustrated
   below.  The IP layer operates on top of the EtherType Protocol
   Discrimination (EPD); this Discrimination layer is described in IEEE
   Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP
   (Link Layer Control Service Accesss Point).


           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           |                 IPv6                  |
           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+
                       {   LLC_SAP  }                 802.11 OCB
           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+  Boundary
           |            EPD          |       |     |
           |                         | MLME  |     |
           +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   |
           |      MAC Sublayer       |       |     |  802.11 OCB
           |     and ch. coord.      |       | SME |  Services
           +-+-+-{   PHY_SAP  }+-+-+-+-+-+-+-|     |
           |                         | PLME  |     |
           |            PHY Layer    |   PLME_SAP  |
           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   In addition to the description of interface between IP and MAC using
   "Ethernet Adaptation Layer" and "Ethernet Protocol Discrimination
   (EPD)" it is worth mentioning that SNAP [RFC1042] is used to carry
   the IPv6 Ethertype.

   However, there may be some deployment considerations helping optimize
   the performances of running IPv6 over 802.11-OCB (e.g. in the case of
   handovers between 802.11 OCB-enabled access routers, or the
   consideration of using the IP security layer [RFC4301]).




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   There are currently no specifications for handover between OCB links
   since these are currently specified as LLC-1 links (i.e.
   connectionless).  Any handovers must be performed above the Data Link
   Layer.  Also, while there is no encryption applied below the network
   layer using 802.11p, 1609.2 [ieee1609.2] does provide security
   services for applications to use so that there can easily be data
   security over the air without invoking IPsec.

   We briefly introduce the vehicular communication scenarios where IEEE
   802.11-OCB links are used.


[Sri] I have not seen much discussion on the link / communication assumptio=
ns.



 This is followed by a description of
   differences in specification terms, between 802.11 OCB and
   802.11a/b/g/n (and the same differences expressed in terms of
   requirements to software implementation are listed in Appendix B.)

   The document then concentrates on the parameters of layering IP over
   802.11 OCB as over Ethernet: value of MTU, the contents of Frame
   Format, the rules for forming Interface Identifiers, the mechanism
   for Address Mapping and for State-less Address Auto-configuration.
   These are precisely the same as IPv6 over Ethernet [RFC2464].

   As an example, these characteristics of layering IPv6 straight over
   LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet
   captured over a 802.11 OCB link; this is described in the section
   Section 6.

   A couple of points can be considered as different, although they are
   not required in order to have a working implementation of IPv6-over-
   802.11-OCB.  These points are consequences of the OCB operation which
   is particular to 802.11 OCB (Outside the Context of a BSS).  First,
   the handovers between OCB links need specific behaviour for IP Router
   Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of
   higher layer messages such as the 'Basic Safety Message' (in the US)
   or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE
   Routing Advertisement'; second, the IP security mechanisms are
   necessary, since OCB means that 802.11 is stripped of all 802.11
   link-layer security; a small additional security aspect which is
   shared between 802.11 OCB and other 802.11 links is the privacy
   concerns related to the address formation mechanisms.

   In the published literature, many documents describe aspects related
   to running IPv6 over 802.11 OCB:
   [I-D.jeong-ipwave-vehicular-networking-survey].


2.  Terminology


   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].



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   RSU: Road Side Unit.  A computer equipped with at least one IEEE
   802.11 interface operated in OCB mode.  This definition applies to
   this document.  An RSU may be connected to the Internet, and may be
   equipped with additional wired or wireless network interfaces running
   IP.  An RSU MAY be an IP Router.



[Sri] RSU can be compared to an 802.11 access point; Or, WTP as defined in =
CAPWAP specification, RFC5415.


Perhaps. rephrase as below?:


"RSU: Road Side Unit. Its a wireless termination point (WTP), as defined in=
 RFC5415 with one key difference, where the wireless physical and the mac l=
ayer is configured to operate in 802.11 OCB mode.  The RSU communicates wit=
h the On board Unit (OBU) in the vehicle over 802.11 wireless link operatin=
g in OCB mode.=94



** Also, since you are defining the RSU term, should you also not define OB=
U (On board Unit) in the vehicle which is the entity on the other end of th=
e link? =93RSU ----802.11-OCB=97=97OBU=94 ? May be introduce the OCB defini=
tion separately, just as you did with RSU, and show the communication link =
as 802.11-OCB.



   OCB: outside the context of a basic service set (BSS): A mode of
   operation in which a STA is not a member of a BSS and does not
   utilize IEEE Std 802.11 authentication, association, or data
   confidentiality.

   802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is
   flagged by "dot11OCBActivated".  This means: IEEE 802.11e for quality
   of service; 802.11j-2004 for half-clocked operations; and (what was
   known earlier as) 802.11p for operation in the 5.9 GHz band and in
   mode OCB.



[Sri] The text starting with. =93This means=94 is not clear to me. Does it =
802.11e is supported with 802.11OCB mode. Please clarify



3.  Communication Scenarios where IEEE 802.11 OCB Links are Used


   The IEEE 802.11 OCB Networks are used for vehicular communications,
   as 'Wireless Access in Vehicular Environments'.  The IP communication
   scenarios for these environments have been described in several
   documents, among which we refer the reader to one recently updated
   [I-D.petrescu-its-scenarios-reqs], about s=
cenarios and requirements
   for IP in Intelligent Transportation Systems.



[Sri] You can do bit more justice to this section.

Explain the link model.  =93STA ----802.11-OCB=97=97STA=94. Then talk about=
 the applicability in Vehicular networks, with STA's as RSU and OCB.

You may also want to talk about, how links get formed/terminated; how nodes=
 peer/discover and how mobility works ..etc.  While 802.11-OCB is clearly s=
pecified and the use of IPv6 over such link is also not radically new, but =
the operating environment which is vehicular brings many new things. That d=
escription is not present any where.


4.  Aspects introduced by the OCB mode to 802.11


   In the IEEE 802.11 OCB mode, all nodes in the wireless range can
   directly communicate with each other without authentication/
   association procedures.  Briefly, the IEEE 802.11 OCB mode has the
   following properties:



[Sri] Can you add some text on how nodes (ST1 and STA2) discover each other=
 on such links supporting 802.11 OCB mode.

   o  The use by each node of a 'wildcard' BSSID (i.e., each bit of the
      BSSID is set to 1)

   o  No IEEE 802.11 Beacon frames transmitted

   o  No authentication required

   o  No association needed

   o  No encryption provided


[Sri] Can you clarify what you mean when you say =93No xxx required=94 / =
=93No xxx needed=94  for the above capabilities.  What does =93needed=94 or=
 =93required=94 mean?  Does it mean, =93Authentication", =93Association" an=
d =93Encryption=94 is optional on this link, or that its not supported on 8=
02.11 OCB links.


   o  Flag dot11OCBActivated set to true

   The following message exchange diagram illustrates a comparison
   between traditional 802.11 and 802.11 in OCB mode.  The 'Data'



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   messages can be IP messages such as the messages used in Stateless or
   Stateful Address Auto-Configuration, or other IP messages.



[Sri] Lets separate the discussion on IP Address configuration using SLAAC/=
DHCP on such links from the above description. The Data packets here can be=
 application packets such as HTTP or other packets. May be additional discu=
ssion is needed on the IP address configuration on 802.11-OCB links.



Other
   802.11 management and control frames (non IP) may be transmitted, as
   specified in the 802.11 standard.  For information, the names of
   these messages as currently specified by the 802.11 standard are
   listed in Appendix D.







     STA                    AP              STA1                   STA2
     |                      |               |                      |
     |<------ Beacon -------|               |<------ Data -------->|
     |                      |               |                      |
     |---- Probe Req. ----->|               |<------ Data -------->|
     |<--- Probe Res. ------|               |                      |
     |                      |               |<------ Data -------->|
     |---- Auth Req. ------>|               |                      |
     |<--- Auth Res. -------|               |<------ Data -------->|
     |                      |               |                      |
     |---- Asso Req. ------>|               |<------ Data -------->|
     |<--- Asso Res. -------|               |                      |
     |                      |               |<------ Data -------->|
     |<------ Data -------->|               |                      |
     |<------ Data -------->|               |<------ Data -------->|

    (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode


   The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010
   [ieee802.11p-2010] as an amendment to IEEE Std 802.11 (TM=
) -2007,
   titled "Amendment 6: Wireless Access in Vehicular Environments".
   Since then, this amendment has been included in IEEE 802.11(TM)-2012
   [ieee802.11-2012], titled "IEEE Standard for Information t=
echnology--
   Telecommunications and information exchange between systems Local and
   metropolitan area networks--Specific requirements Part 11: Wireless
   LAN Medium Access Control (MAC) and Physical Layer (PHY)
   Specifications"; the modifications are diffused throughout various
   sections (e.g. the Time Advertisement message described in the
   earlier 802.11 (TM) p amendment is now described in section 'Frame
   formats', and the operation outside the context of a BSS described in
   section 'MLME').

   In document 802.11-2012, specifically anything referring
   "OCBActivated", or "outside the context of a basic service set" is
   actually referring to the 802.11p aspects introduced to 802.11.  Note
   that in earlier 802.11p documents the term "OCBEnabled" was used
   instead of te current "OCBActivated".





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   In order to delineate the aspects introduced by 802.11 OCB to 802.11,
   we refer to the earlier [ieee802.11p-2010].  The amendmen=
t is
   concerned with vehicular communications, where the wireless link is
   similar to that of Wireless LAN (using a PHY layer specified by
   802.11a/b/g/n), but which needs to cope with the high mobility factor
   inherent in scenarios of communications between moving vehicles, and
   between vehicles and fixed infrastructure deployed along roads.
   While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is
   concerned more with MAC modifications, and a little with PHY
   modifications; the others are mainly about PHY modifications.  It is
   possible in practice to combine a 'p' MAC with an 'a' PHY by
   operating outside the context of a BSS with OFDM at 5.4GHz.

   The 802.11 OCB links are specified to be compatible as much as
   possible with the behaviour of 802.11a/b/g/n and future generation
   IEEE WLAN links.  From the IP perspective, an 802.11 OCB MAC layer
   offers practically the same interface to IP as the WiFi and Ethernet
   layers do (802.11a/b/g/n and 802.3).


[Sri] A packet sent from a vehicle=92s OBU is received by a single RSU, or =
multiple RSU=92s? How does the link-layer resolution happen?


   To support this similarity statement (IPv6 is layered on top of LLC
   on top of 802.11 OCB similarly as on top of LLC on top of
   802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to
   analyze the differences between 802.11 OCB and 802.11 specifications.
   Whereas the 802.11p amendment specifies relatively complex and
   numerous changes to the MAC layer (and very little to the PHY layer),
   we note there are only a few characteristics which may be important
   for an implementation transmitting IPv6 packets on 802.11 OCB links.

   In the list below, the only 802.11 OCB fundamental points which
   influence IPv6 are the OCB operation and the 12Mbit/s maximum which
   may be afforded by the IPv6 applications.



[Sri] I am really not sure how link throughput (12Mbps) relates to "IPv6 su=
pport on OCB links".



   o  Operation Outside the Context of a BSS (OCB): the (earlier
      802.11p) 802.11-OCB links are operated without a Basic Service Set
      (BSS).  This means that the frames IEEE 802.11 Beacon, Association
      Request/Response, Authentication Request/Response, and similar,
      are not used.  The used identifier of BSS (BSSID) has a
      hexadecimal value always 0xffffffffffff (48 '1' bits, represented
      as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'
      BSSID), as opposed to an arbitrary BSSID value set by
      administrator (e.g.  'My-Home-AccessPoint').  The OCB operation -
      namely the lack of beacon-based scanning and lack of
      authentication - has a potentially strong impact on the use of the
      Mobile IPv6 protocol [RFC6275] a=
nd on the protocols for IP layer
      security [RFC4301].



[Sri] The document till now has been arguing heavily on how IPv6 operates s=
o naturally on these links and now I see discussion on =93Impact to a high-=
level protocol such as MIPv6=94. You may want to fix the earlier text. In a=
ny case,  the absence of link-layer security practically impacts every appl=
ication, not just MIPv6.  Also, MIPv6 does not make any assumptions on the =
link-layer security.  Also, the the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes=
 the messages readable by all other RSU=92s in proximity. I think the discu=
ssion on the nature of the link, who all see=92s the messages.. how L2 addr=
esses are resolved is not explained clearly.




   o  Timing Advertisement: is a new message defined in 802.11-OCB,
      which does not exist in 802.11a/b/g/n.  This message is used by



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      stations to inform other stations about the value of time.  It is
      similar to the time as delivered by a GNSS system (Galileo, GPS,
      ...) or by a cellular system.  This message is optional for
      implementation.  At the date of writing, an experienced reviewer
      considers that currently no field testing has used this message.
      Another implementor considers this feature implemented in an
      initial manner.  In the future, it is speculated that this message
      may be useful for very simple devices which may not have their own
      hardware source of time (Galileo, GPS, cellular network), or by
      vehicular devices situated in areas not covered by such network
      (in tunnels, underground, outdoors but shaded by foliage or
      buildings, in remote areas, etc.)



[Sri] The first part explaining Timing Advertisement messages is great, but=
 the rest of the commentary is unnecessary and not needed. We don=92t specu=
late the protocol adoption success in IETF specifications, or about the exp=
erience level of the =93reviewer" :)



   o  Frequency range: this is a characteristic of the PHY layer, with
      almost no impact to the interface between MAC and IP.  However, it
      is worth considering that the frequency range is regulated by a
      regional authority (ARCEP, ETSI, FCC, etc.); as part of the
      regulation process, specific applications are associated with
      specific frequency ranges.  In the case of 802.11-OCB, the
      regulator associates a set of frequency ranges, or slots within a
      band, to the use of applications of vehicular communications, in a
      band known as "5.9GHz".  This band is "5.9GHz" which is different
      from the bands "2.4GHz" or "5GHz" used by Wireless LAN.  However,
      as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz"
      bands is exempt from owning a license in EU (in US the 5.9GHz is a
      licensed band of spectrum; for the the fixed infrastructure an
      explicit FCC autorization is required; for an onboard device a
      'licensed-by-rule' concept applies: rule certification conformity
      is required); however technical conditions are different than
      those of the bands "2.4GHz" or "5GHz".  On one hand, the allowed
      power levels, and implicitly the maximum allowed distance between
      vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20
      dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum
      distance of approximately 1km, compared to approximately 50m.  On
      the other hand, specific conditions related to congestion
      avoidance, jamming avoidance, and radar detection are imposed on
      the use of DSRC (in US) and on the use of frequencies for
      Intelligent Transportation Systems (in EU), compared to Wireless
      LAN (802.11a/b/g/n).

   o  Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB,
      as opposed to IPv6 not being prohibited on any channel on which
      802.11a/b/g/n runs:

      *  Some channels are reserved for safety communications; the IPv6
         packets should not be sent on these channels.





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7


      *  At the time of writing, the prohibition is explicit at higher
         layer protocols providing services to the application; these
         higher layer protocols are specified in IEEE 1609 documents.

      *  National or regional specifications and regulations specify the
         use of different channels; these regulations must be followed.

   o  'Half-rate' encoding: as the frequency range, this parameter is
      related to PHY, and thus has not much impact on the interface
      between the IP layer and the MAC layer.

   o  In vehicular communications using 802.11-OCB links, there are
      strong privacy requirements with respect to addressing.  While the
      802.11-OCB standard does not specify anything in particular with
      respect to MAC addresses, in these settings there exists a strong
      need for dynamic change of these addresses (as opposed to the non-
      vehicular settings - real wall protection - where fixed MAC
      addresses do not currently pose some privacy risks).  This is
      further described in section Section 7.  A relevant function is
      described in IEEE 1609.3-2016 [ieee1609.3], clause 5.5.1 and=
 IEEE
      1609.4-2016 [ieee1609.4], clause 6.7.



   Other aspects particular to 802.11-OCB which are also particular to
   802.11 (e.g. the 'hidden node' operation) may have an influence on
   the use of transmission of IPv6 packets on 802.11-OCB networks.  The
   subnet structure which may be assumed in 802.11-OCB networks is
   strongly influenced by the mobility of vehicles.


[Sri] Per my earlier comment, the link model, addressing ..etc needs to be =
explained in more detail. It is not clear what exactly the =93subnet struct=
ure=94 that is assumed in 802.11-OCB.


5.  Layering of IPv6 over 802.11-OCB as over Ethernet
5.1.  Maximum Transmission Unit (MTU)


   The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is
   the same value as IPv6 packets on Ethernet links, as specified in
   [RFC2464].  This value of the MTU r=
espects the recommendation that
   every link in the Internet must have a minimum MTU of 1280 octets
   (stated in [RFC2460], and the recom=
mendations therein, especially
   with respect to fragmentation).  If IPv6 packets of size larger than
   1500 bytes are sent on an 802.11-OCB interface card then the IP stack
   will fragment.  In case there are IP fragments, the field "Sequence
   number" of the 802.11 Data header containing the IP fragment field is
   increased.

   Non-IP packets such as WAVE Short Message Protocol (WSMP) can be
   delivered on 802.11-OCB links.  Specifications of these packets are
   out of scope of this document, and do not impose any limit on the MTU
   size, allowing an arbitrary number of 'containers'.  Non-IP packets
   such as ETSI 'geonet' packets have an MTU of 1492 bytes.



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   The Equivalent Transmit Time on Channel is a concept that may be used
   as an alternative to the MTU concept.  A rate of transmission may be
   specified as well.  The ETTC, rate and MTU may be in direct
   relationship.


[Sri] The last paragraph needs some additional context. Did 802.11-OCB intr=
oduce ETTC concept?




5.2.  Frame Format


   IP packets are transmitted over 802.11-OCB as standard Ethernet
   packets.  As with all 802.11 frames, an Ethernet adaptation layer is
   used with 802.11-OCB as well.  This Ethernet Adaptation Layer
   performing 802.11-to-Ethernet is described in Section 5.2.1.  Th=
e
   Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD,
   or otherwise #86DD).

   The Frame format for transmitting IPv6 on 802.11-OCB networks is the
   same as transmitting IPv6 on Ethernet networks, and is described in
   section 3 of [RFC2464].  =
The frame format for transmitting IPv6
   packets over Ethernet is illustrated below:


                    0                   1
                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |          Destination          |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |             Source            |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |             IPv6              |
                    +-                             -+
                    |            header             |
                    +-                             -+
                    |             and               |
                    +-                             -+
                    /            payload ...        /
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    (Each tic mark represents one bit.)





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   Ethernet II Fields:

   Destination Ethernet Address
      the MAC destination address.

   Source Ethernet Address
      the MAC source address.

   1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
      binary representation of the EtherType value 0x86DD.

   IPv6 header and payload
      the IPv6 packet containing IPv6 header and payload.


5.2.1.  Ethernet Adaptation Layer


   In general, an 'adaptation' layer is inserted between a MAC layer and
   the Networking layer.  This is used to transform some parameters
   between their form expected by the IP stack and the form provided by
   the MAC layer.  For example, an 802.15.4 adaptation layer may perform
   fragmentation and reassembly operations on a MAC whose maximum Packet
   Data Unit size is smaller than the minimum MTU recognized by the IPv6
   Networking layer.  Other examples involve link-layer address
   transformation, packet header insertion/removal, and so on.

   An Ethernet Adaptation Layer makes an 802.11 MAC look to IP
   Networking layer as a more traditional Ethernet layer.  At reception,
   this layer takes as input the IEEE 802.11 Data Header and the
   Logical-Link Layer Control Header and produces an Ethernet II Header.
   At sending, the reverse operation is performed.


 +--------------------+------------+-------------+---------+-----------+
 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer|
 +--------------------+------------+-------------+---------+-----------+
  \                               /                         \         /
    -----------------------------                             --------
                   ^---------------------------------------------/
                   |
           802.11-to-Ethernet Adaptation Layer
                   |
                   v
 +---------------------+-------------+---------+
 | Ethernet II Header  | IPv6 Header | Payload |
 +---------------------+-------------+---------+






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   The Receiver and Transmitter Address fields in the 802.11 Data Header
   contain the same values as the Destination and the Source Address
   fields in the Ethernet II Header, respectively.  The value of the
   Type field in the LLC Header is the same as the value of the Type
   field in the Ethernet II Header.

   The ".11 Trailer" contains solely a 4-byte Frame Check Sequence.

   The Ethernet Adaptation Layer performs operations in relation to IP
   fragmentation and MTU.  One of these operations is briefly described
   in section Section 5.1.

   In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11
   Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in
   the following figure:


+--------------------+-------------+-------------+---------+-----------+
| 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------+-----------+

or

+--------------------+-------------+-------------+---------+-----------+
| 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------+-----------+


   The distinction between the two formats is given by the value of the
   field "Type/Subtype".  The value of the field "Type/Subtype" in the
   802.11 Data header is 0x0020.  The value of the field "Type/Subtype"
   in the 802.11 QoS header is 0x0028.

   The mapping between qos-related fields in the IPv6 header (e.g.
   "Traffic Class", "Flow label") and fields in the "802.11 QoS Data
   Header" (e.g.  "QoS Control") are not specified in this document.
   Guidance for a potential mapping is provided in
   [I-D.ietf-tsvwg-ieee-802-11], although it is no=
t specific to OCB
   mode.




[Sri] The applicability of the QoS mapping draft to 802.11-OCB needs furthe=
r investigation, IMO.




5.3.  Link-Local Addresses


   The link-local address of an 802.11-OCB interface is formed in the
   same manner as on an Ethernet interface.  This manner is described in
   section 5 of [RFC2464].




[Sri] Does this go against the 8064 recommendation on Interface identifier =
generation?

May be RFC7217 for interface identifier generation in conjunction with the =
link-local address generation per RFC2464

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5.4.  Address Mapping


   For unicast as for multicast, there is no change from the unicast and
   multicast address mapping format of Ethernet interfaces, as defined
   by sections 6 and 7 of [RFC2464].




[Sri] RFC6085 specified mapping is also relevant; If the communication peer=
s are aware that there is only one peer, it should apply 6085 specified map=
ping. That mode is relevant for 802.11-OCB types links as well.



5.4.1.  Address Mapping -- Unicast


   The procedure for mapping IPv6 unicast addresses into Ethernet link-
   layer addresses is described in [RFC4861].  The Source/Target Link-
   layer Address option has the following form when the link-layer is
   Ethernet.


[Sri] I thought, mapping of IPv6 unicast addresses to Ethernet link-layer a=
ddresses is specified in section 6, of RFC2464 and not in RFC4861.




                      0                   1
                      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |     Type      |    Length     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |                               |
                     +-          Ethernet           -+
                     |                               |
                     +-           Address           -+
                     |                               |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Option fields:

   Type
      1 for Source Link-layer address.
      2 for Target Link-layer address.

   Length
      1 (in units of 8 octets).

   Ethernet Address
      The 48 bit Ethernet IEEE 802 address, in canonical bit order.


5.4.2.  Address Mapping -- Multicast


   IPv6 protocols often make use of IPv6 multicast addresses in the
   destination field of IPv6 headers.  For example, an ICMPv6 link-
   scoped Neighbor Advertisement is sent to the IPv6 address ff02::1
   denoted "all-nodes" address.  When transmitting these packets on
   802.11-OCB links it is necessary to map the IPv6 address to a MAC
   address.




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   The same mapping requirement applies to the link-scoped multicast
   addresses of other IPv6 protocols as well.  In DHCPv6, the
   "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF the
   "All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped
   on a multicast MAC address.

   An IPv6 packet with a multicast destination address DST, consisting
   of the sixteen octets DST[1] through DST[16], is transmitted to the
   IEEE 802.11-OCB MAC multicast address whose first two octets are the
   value 0x3333 and whose last four octets are the last four octets of
   DST.


[Sri] Please add a reference to Section 7, RFC4861 and also RFC6085. In gen=
eral, for both unicast and multicast, you may want to clearly say that this=
 is per the existing specs and duplicated here for convenience.


                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |   DST[13]     |   DST[14]     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |   DST[15]     |   DST[16]     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   A Group ID TBD of length 112bits may be requested from IANA; this
   Group ID signifies "All 80211OCB Interfaces Address".  Only the least
   32 significant bits of this "All 80211OCB Interfaces Address" will be
   mapped to and from a MAC multicast address.

   Transmitting IPv6 packets to multicast destinations over 802.11 links
   proved to have some performance issues
   [I-D.perkins-intarea-multicast-ieee802].  These issues may be
   exacerbated in OCB mode.  Solutions for these problems should
   consider the OCB mode of operation.


5.5.  Stateless Autoconfiguration


   The Interface Identifier for an 802.11-OCB interface is formed using
   the same rules as the Interface Identifier for an Ethernet interface;
   this is described in section 4 of [RFC2464].  No changes are needed,
   but some care must be taken when considering the use of the SLAAC
   procedure.



[Sri] Per my earlier comment, please refer to the current recommendation on=
 interface-identifier generation and its use in link-local, global or other=
 addresses.

The bits in the the interface identifier have no generic meaning and the id=
entifier should be treated as an opaque value. The bits 'Universal' and 'Gr=
oup' in the identifier of an 802.11-OCB interface are significant, as this =
is an IEEE link-layer address. The details of this significance are describ=
ed in [I-D.ietf-6man-ug]. Petrescu, et al. Expires February =
18, 2018 [Page 15]

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   As with all Ethernet and 802.11 interface identifiers ([RFC7721]),
   the identifier of an 802.11-OCB interface may involve privacy risks.
   A vehicle embarking an On-Board Unit whose egress interface is
   802.11-OCB may expose itself to eavesdropping and subsequent
   correlation of data; this may reveal data considered private by the
   vehicle owner; there is a risk of being tracked; see the privacy
   considerations described in Appendix C.



[Sri] I think there are other security issues here; the absence of link-lay=
er security opens up Mac-spoofing and IP address hijacking.  That should be=
 mentioned.



   If stable Interface Identifiers are needed in order to form IPv6
   addresses on 802.11-OCB links, it is recommended to follow the
   recommendation in [I-D.ietf-6man-default-iids].


5.6.  Subnet Structure


   The 802.11 networks in OCB mode may be considered as 'ad-hoc'
   networks.  The addressing model for such networks is described in
   [RFC5889].



[Sri] Per my earlier comment, there is no system level view of the network =
where 802.11-OCB links are used. So, in the absence of such discussion So, =
I am not sure what part of RFC5889 is applicable here. For example, link-lo=
cal addresses may just work fine.



6.  Example IPv6 Packet captured over a IEEE 802.11-OCB link


   We remind that a main goal of this document is to make the case that
   IPv6 works fine over 802.11-OCB networks.  Consequently, this section
   is an illustration of this concept and thus can help the implementer
   when it comes to running IPv6 over IEEE 802.11-OCB.  By way of
   example we show that there is no modification in the headers when
   transmitted over 802.11-OCB networks - they are transmitted like any
   other 802.11 and Ethernet packets.

   We describe an experiment of capturing an IPv6 packet on an
   802.11-OCB link.  In this experiment, the packet is an IPv6 Router
   Advertisement.  This packet is emitted by a Router on its 802.11-OCB
   interface.  The packet is captured on the Host, using a network
   protocol analyzer (e.g.  Wireshark); the capture is performed in two
   different modes: direct mode and 'monitor' mode.  The topology used
   during the capture is depicted below.


              +--------+                                +-------+
              |        |        802.11-OCB Link         |       |
           ---| Router |--------------------------------| Host  |
              |        |                                |       |
              +--------+                                +-------+


   During several capture operations running from a few moments to
   several hours, no message relevant to the BSSID contexts were
   captured (no Association Request/Response, Authentication Req/Resp,




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   Beacon).  This shows that the operation of 802.11-OCB is outside the
   context of a BSSID.

   Overall, the captured message is identical with a capture of an IPv6
   packet emitted on a 802.11b interface.  The contents are precisely
   similar.



[Sri] I suggest moving this discussion under the section =93Implementation =
Status=94, which will eventually be removed from the RFC. There is nothing =
new here. This are details on experimentation. But, if you think there is s=
ome useful information  such as discussion on Capture mode ..etc, you may w=
ant to move this entire section to Appendix. Implementors may use these too=
ls for verification.




6.1.  Capture in Monitor Mode


   The IPv6 RA packet captured in monitor mode is illustrated below.
   The radio tap header provides more flexibility for reporting the
   characteristics of frames.  The Radiotap Header is prepended by this
   particular stack and operating system on the Host machine to the RA
   packet received from the network (the Radiotap Header is not present
   on the air).  The implementation-dependent Radiotap Header is useful
   for piggybacking PHY information from the chip's registers as data in
   a packet understandable by userland applications using Socket
   interfaces (the PHY interface can be, for example: power levels, data
   rate, ratio of signal to noise).

   The packet present on the air is formed by IEEE 802.11 Data Header,
   Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.



     Radiotap Header v0
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Header Revision|  Header Pad   |    Header length              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Present flags                         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Data Rate     |             Pad                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IEEE 802.11 Data Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Type/Subtype and Frame Ctrl  |          Duration             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Receiver Address...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Receiver Address           |      Transmitter Address...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Transmitter Address                                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                            BSS Id...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... BSS Id                     |  Frag Number and Seq Number   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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     Logical-Link Control Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |      DSAP   |I|     SSAP    |C| Control field | Org. code...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Organizational Code        |             Type              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                         Source Address                        +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                      Destination Address                      +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+-


   The value of the Data Rate field in the Radiotap header is set to 6
   Mb/s.  This indicates the rate at which this RA was received.





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   The value of the Transmitter address in the IEEE 802.11 Data Header
   is set to a 48bit value.  The value of the destination address is
   33:33:00:00:00:1 (all-nodes multicast address).  The value of the BSS
   Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network
   protocol analyzer as being "broadcast".  The Fragment number and
   sequence number fields are together set to 0x90C6.

   The value of the Organization Code field in the Logical-Link Control
   Header is set to 0x0, recognized as "Encapsulated Ethernet".  The
   value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise
   #86DD), recognized as "IPv6".

   A Router Advertisement is periodically sent by the router to
   multicast group address ff02::1.  It is an icmp packet type 134.  The
   IPv6 Neighbor Discovery's Router Advertisement message contains an
   8-bit field reserved for single-bit flags, as described in [RFC4861].

   The IPv6 header contains the link local address of the router
   (source) configured via EUI-64 algorithm, and destination address set
   to ff02::1.  Recent versions of network protocol analyzers (e.g.
   Wireshark) provide additional informations for an IP address, if a
   geolocalization database is present.  In this example, the
   geolocalization database is absent, and the "GeoIP" information is
   set to unknown for both source and destination addresses (although
   the IPv6 source and destination addresses are set to useful values).
   This "GeoIP" can be a useful information to look up the city,
   country, AS number, and other information for an IP address.


[Sri] Not sure, why all of this text should be in the specification.


   The Ethernet Type field in the logical-link control header is set to
   0x86dd which indicates that the frame transports an IPv6 packet.  In
   the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
   which is he corresponding multicast MAC address.  The BSS id is a
   broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link
   duration between vehicles and the roadside infrastructure, there is
   no need in IEEE 802.11-OCB to wait for the completion of association
   and authentication procedures before exchanging data.  IEEE
   802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)
   and may start communicating as soon as they arrive on the
   communication channel.


6.2.  Capture in Normal Mode


   The same IPv6 Router Advertisement packet described above (monitor
   mode) is captured on the Host, in the Normal mode, and depicted
   below.






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     Ethernet II Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Destination...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ...Destination                 |           Source...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ...Source                                                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |          Type                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                         Source Address                        +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                      Destination Address                      +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+-





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   One notices that the Radiotap Header is not prepended, and that the
   IEEE 802.11 Data Header and the Logical-Link Control Headers are not
   present.  On another hand, a new header named Ethernet II Header is
   present.

   The Destination and Source addresses in the Ethernet II header
   contain the same values as the fields Receiver Address and
   Transmitter Address present in the IEEE 802.11 Data Header in the
   "monitor" mode capture.

   The value of the Type field in the Ethernet II header is 0x86DD
   (recognized as "IPv6"); this value is the same value as the value of
   the field Type in the Logical-Link Control Header in the "monitor"
   mode capture.

   The knowledgeable experimenter will no doubt notice the similarity of
   this Ethernet II Header with a capture in normal mode on a pure
   Ethernet cable interface.

   It may be interpreted that an Adaptation layer is inserted in a pure
   IEEE 802.11 MAC packets in the air, before delivering to the
   applications.  In detail, this adaptation layer may consist in
   elimination of the Radiotap, 802.11 and LLC headers and insertion of
   the Ethernet II header.  In this way, it can be stated that IPv6 runs
   naturally straight over LLC over the 802.11-OCB MAC layer, as shown
   by the use of the Type 0x86DD, and assuming an adaptation layer
   (adapting 802.11 LLC/MAC to Ethernet II header).


7.  Security Considerations


   Any security mechanism at the IP layer or above that may be carried
   out for the general case of IPv6 may also be carried out for IPv6
   operating over 802.11-OCB.



   802.11-OCB does not provide any cryptographic protection, because it
   operates outside the context of a BSS (no Association Request/
   Response, no Challenge messages).  Any attacker can therefore just
   sit in the near range of vehicles, sniff the network (just set the
   interface card's frequency to the proper range) and perform attacks
   without needing to physically break any wall.  Such a link is way
   less protected than commonly used links (wired link or protected
   802.11).


[Sri] Per my earlier comment, there is more than one attack vector possible

1.) Absence of link-layer security and the potential for mac address spoofi=
ng

2.) IP address / Session hijacking

3.) Data privacy per your text



   At the IP layer, IPsec can be used to protect unicast communications,
   and SeND can be used for multicast communications.


[Sri] IPSec can be used for protecting both multicast or unicast communicat=
ion; RFC-5374 with GDOI.




 If no protection
   is used by the IP layer, upper layers should be protected.
   Otherwise, the end-user or system should be warned about the risks
   they run.



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   As with all Ethernet and 802.11 interface identifiers, there may
   exist privacy risks in the use of 802.11-OCB interface identifiers.
   Moreover, in outdoors vehicular settings, the privacy risks are more
   important than in indoors settings.  New risks are induced by the
   possibility of attacker sniffers deployed along routes which listen
   for IP packets of vehicles passing by.  For this reason, in the
   802.11-OCB deployments, there is a strong necessity to use protection
   tools such as dynamically changing MAC addresses.  This may help
   mitigate privacy risks to a certain level.  On another hand, it may
   have an impact in the way typical IPv6 address auto-configuration is
   performed for vehicles (SLAAC would rely on MAC addresses amd would
   hence dynamically change the affected IP address), in the way the
   IPv6 Privacy addresses were used, and other effects.


8.  IANA Considerations
9.  Contributors


   Romain Kuntz contributed extensively about IPv6 handovers between
   links running outside the context of a BSS (802.11-OCB links).

   Tim Leinmueller contributed the idea of the use of IPv6 over
   802.11-OCB for distribution of certificates.

   Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey
   Voronov provided significant feedback on the experience of using IP
   messages over 802.11-OCB in initial trials.

   Michelle Wetterwald contributed extensively the MTU discussion,
   offered the ETSI ITS perspective, and reviewed other parts of the
   document.


10.  Acknowledgements


   The authors would like to thank Witold Klaudel, Ryuji Wakikawa,
   Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan
   Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray
   Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,
   Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,
   Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,
   Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and
   William Whyte.  Their valuable comments clarified certain issues and
   generally helped to improve the document.

   Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB
   drivers for linux and described how.





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   For the multicast discussion, the authors would like to thank Owen
   DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and
   participants to discussions in network working groups.

   The authours would like to thank participants to the Birds-of-
   a-Feather "Intelligent Transportation Systems" meetings held at IETF
   in 2016.


11.  References
11.1.  Normative References


   [I-D.ietf-6man-default-iids]
              Gont, F., Cooper, A., Thaler, D., and S. LIU,
              "Recommendation on Stable IPv6 Interface Identifiers",
              draft-ietf-6man-default-iids-16 (work in progress),
              September 2016.

   [I-D.ietf-6man-ug]
              Carpenter, B. and S. Jiang, "Significance of IPv6
              Interface Identifiers", draft-ietf-6man-ug-06 (work in
              progress), December 2013.

   [I-D.ietf-tsvwg-ieee-802-11]
              Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE
              802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-06 (work in
              progress), August 2017.

   [RFC1042]  Postel, J. and J. Reynolds, "Standard for the transmission
              of IP datagrams over IEEE 802 networks", STD 43, RFC 1042,
              DOI 10.17487/RFC1042, February 1988, 
              editor.org/info/rfc1042>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997, 
              editor.org/info/rfc2119>.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
              December 1998, .

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, DOI=
 10.17487/RFC2464, December 1998,
              .






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   [RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol",
              RFC 3963, DOI 10.17487/R=
FC3963, January 2005,
              .

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security", BCP 106, RFC 4086,
              DOI 10.17487/RFC4086, June 2005, 
              editor.org/info/rfc4086>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, .

   [RFC4429]  Moore, N., "Optimistic Duplicate Address Detection (DAD)
              for IPv6", RFC 4429, DOI=
 10.17487/RFC4429, April 2006,
              .

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007, 
              editor.org/info/rfc4861>.

   [RFC5889]  Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing
              Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889,
              September 2010, .

   [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
              2011, .

   [RFC6775]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
              Bormann, "Neighbor Discovery Optimization for IPv6 over
              Low-Power Wireless Personal Area Networks (6LoWPANs)",
              RFC 6775, DOI 10.17487/R=
FC6775, November 2012,
              .

   [RFC7721]  Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
              Considerations for IPv6 Address Generation Mechanisms",
              RFC 7721, DOI 10.17487/R=
FC7721, March 2016,
              .


11.2.  Informative References
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   [fcc-cc]   "'Report and Order, Before the Federal Communications
              Commission Washington, D.C. 20554', FCC 03-324, Released
              on February 10, 2004, document FCC-03-324A1.pdf, document
              freely available at URL
              http://www.its.dot.gov/exit/fcc_edocs.htm downloaded on
              October 17th, 2013.".

   [fcc-cc-172-184]
              "'Memorandum Opinion and Order, Before the Federal
              Communications Commission Washington, D.C. 20554', FCC
              06-10, Released on July 26, 2006, document FCC-
              06-110A1.pdf, document freely available at URL
              http://hraunfoss.fcc.gov/edocs_public/attachmatch/
              FCC-06-110A1.pdf downloaded on June 5th, 2014.".

   [I-D.jeong-ipwave-vehicular-networking-survey]
              Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M.
              Wetterwald, "Survey on IP-based Vehicular Networking for
              Intelligent Transportation Systems", draft-jeong-ipwave-
              vehicular-networking-survey-03 (work in progress), June
              2017.

   [I-D.perkins-intarea-multicast-ieee802]
              Perkins, C., Stanley, D., Kumari, W., and J. Zuniga,
              "Multicast Considerations over IEEE 802 Wireless Media",
              draft-perkins-intarea-multicast-ieee802-03 (work in
              progress), July 2017.

   [I-D.petrescu-its-scenarios-reqs]
              Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel,
              "Scenarios and Requirements for IP in Intelligent
              Transportation Systems", draft-petrescu-its-scenarios-
              reqs-03 (work in progress), October 2013.

   [ieee1609.2]
              "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Security Services for
              Applications and Management Messages.  Example URL
              http://ieeexplore.ieee.org/document/7426684/ accessed on
              August 17th, 2017.".

   [ieee1609.3]
              "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Networking Services.
              Example URL http://ieeexplore.ieee.org/document/7458115/
              accessed on August 17th, 2017.".





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   [ieee1609.4]
              "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Multi-Channel
              Operation.  Example URL
              http://ieeexplore.ieee.org/document/7435228/ accessed on
              August 17th, 2017.".

   [ieee802.11-2012]
              "802.11-2012 - IEEE Standard for Information technology--
              Telecommunications and information exchange between
              systems Local and metropolitan area networks--Specific
              requirements Part 11: Wireless LAN Medium Access Control
              (MAC) and Physical Layer (PHY) Specifications.  Downloaded
              on October 17th, 2013, from IEEE Standards, document
              freely available at URL
              http://standards.ieee.org/findstds/
              standard/802.11-2012.html retrieved on October 17th,
              2013.".

   [ieee802.11p-2010]
              "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information
              Technology - Telecommunications and information exchange
              between systems - Local and metropolitan area networks -
              Specific requirements, Part 11: Wireless LAN Medium Access
              Control (MAC) and Physical Layer (PHY) Specifications,
              Amendment 6: Wireless Access in Vehicular Environments;
              document freely available at URL
              http://standards.ieee.org/getieee802/
              download/802.11p-2010.pdf retrieved on September 20th,
              2013.".


Appendix A.  ChangeLog


   The changes are listed in reverse chronological order, most recent
   changes appearing at the top of the list.

   From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave-
   ipv6-over-80211ocb-04

   o  Removed a few informative references pointing to Dx draft IEEE
      1609 documents.

   o  Removed outdated informative references to ETSI documents.

   o  Added citations to IEEE 1609.2, .3 and .4-2016.

   o  Minor textual issues.




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   From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave-
   ipv6-over-80211ocb-03

   o  Keep the previous text on multiple addresses, so remove talk about
      MIP6, NEMOv6 and MCoA.

   o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.

   o  Clarified the figure showing Infrastructure mode and OCB mode side
      by side.

   o  Added a reference to the IP Security Architecture RFC.

   o  Detailed the IPv6-per-channel prohibition paragraph which reflects
      the discussion at the last IETF IPWAVE WG meeting.

   o  Added section "Address Mapping -- Unicast".

   o  Added the ".11 Trailer" to pictures of 802.11 frames.

   o  Added text about SNAP carrying the Ethertype.

   o  New RSU definition allowing for it be both a Router and not
      necessarily a Router some times.

   o  Minor textual issues.

   From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave-
   ipv6-over-80211ocb-02

   o  Replaced almost all occurences of 802.11p with 802.11-OCB, leaving
      only when explanation of evolution was necessary.

   o  Shortened by removing parameter details from a paragraph in the
      Introduction.

   o  Moved a reference from Normative to Informative.

   o  Added text in intro clarifying there is no handover spec at IEEE,
      and that 1609.2 does provide security services.

   o  Named the contents the fields of the EthernetII header (including
      the Ethertype bitstring).

   o  Improved relationship between two paragraphs describing the
      increase of the Sequence Number in 802.11 header upon IP
      fragmentation.




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   o  Added brief clarification of "tracking".

   From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave-
   ipv6-over-80211ocb-01

   o  Introduced message exchange diagram illustrating differences
      between 802.11 and 802.11 in OCB mode.

   o  Introduced an appendix listing for information the set of 802.11
      messages that may be transmitted in OCB mode.

   o  Removed appendix sections "Privacy Requirements", "Authentication
      Requirements" and "Security Certificate Generation".

   o  Removed appendix section "Non IP Communications".

   o  Introductory phrase in the Security Considerations section.

   o  Improved the definition of "OCB".

   o  Introduced theoretical stacked layers about IPv6 and IEEE layers
      including EPD.

   o  Removed the appendix describing the details of prohibiting IPv6 on
      certain channels relevant to 802.11-OCB.

   o  Added a brief reference in the privacy text about a precise clause
      in IEEE 1609.3 and .4.

   o  Clarified the definition of a Road Side Unit.

   o  Removed the discussion about security of WSA (because is non-IP).

   o  Removed mentioning of the GeoNetworking discussion.

   o  Moved references to scientific articles to a separate 'overview'
      draft, and referred to it.


Appendix B.  Changes Needed on a software driver 802.11a to become a

             802.11-OCB driver

   The 802.11p amendment modifies both the 802.11 stack's physical and
   MAC layers but all the induced modifications can be quite easily
   obtained by modifying an existing 802.11a ad-hoc stack.

   Conditions for a 802.11a hardware to be 802.11-OCB compliant:





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   o  The chip must support the frequency bands on which the regulator
      recommends the use of ITS communications, for example using IEEE
      802.11-OCB layer, in France: 5875MHz to 5925MHz.

   o  The chip must support the half-rate mode (the internal clock
      should be able to be divided by two).

   o  The chip transmit spectrum mask must be compliant to the "Transmit
      spectrum mask" from the IEEE 802.11p amendment (but experimental
      environments tolerate otherwise).

   o  The chip should be able to transmit up to 44.8 dBm when used by
      the US government in the United States, and up to 33 dBm in
      Europe; other regional conditions apply.

   Changes needed on the network stack in OCB mode:

   o  Physical layer:

      *  The chip must use the Orthogonal Frequency Multiple Access
         (OFDM) encoding mode.

      *  The chip must be set in half-mode rate mode (the internal clock
         frequency is divided by two).

      *  The chip must use dedicated channels and should allow the use
         of higher emission powers.  This may require modifications to
         the regulatory domains rules, if used by the kernel to enforce
         local specific restrictions.  Such modifications must respect
         the location-specific laws.

      MAC layer:

      *  All management frames (beacons, join, leave, and others)
         emission and reception must be disabled except for frames of
         subtype Action and Timing Advertisement (defined below).

      *  No encryption key or method must be used.

      *  Packet emission and reception must be performed as in ad-hoc
         mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).

      *  The functions related to joining a BSS (Association Request/
         Response) and for authentication (Authentication Request/Reply,
         Challenge) are not called.

      *  The beacon interval is always set to 0 (zero).




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      *  Timing Advertisement frames, defined in the amendment, should
         be supported.  The upper layer should be able to trigger such
         frames emission and to retrieve information contained in
         received Timing Advertisements.


Appendix C.  Design Considerations


   The networks defined by 802.11-OCB are in many ways similar to other
   networks of the 802.11 family.  In theory, the encapsulation of IPv6
   over 802.11-OCB could be very similar to the operation of IPv6 over
   other networks of the 802.11 family.  However, the high mobility,
   strong link asymetry and very short connection makes the 802.11-OCB
   link significantly different from other 802.11 networks.  Also, the
   automotive applications have specific requirements for reliability,
   security and privacy, which further add to the particularity of the
   802.11-OCB link.


C.1.  Vehicle ID


   Automotive networks require the unique representation of each of
   their node.  Accordingly, a vehicle must be identified by at least
   one unique identifier.  The current specification at ETSI and at IEEE
   1609 identifies a vehicle by its MAC address uniquely obtained from
   the 802.11-OCB NIC.

   A MAC address uniquely obtained from a IEEE 802.11-OCB NIC
   implicitely generates multiple vehicle IDs in case of multiple
   802.11-OCB NICs.  A mechanims to uniquely identify a vehicle
   irrespectively to the different NICs and/or technologies is required.


C.2.  Reliability Requirements


   The dynamically changing topology, short connectivity, mobile
   transmitter and receivers, different antenna heights, and many-to-
   many communication types, make IEEE 802.11-OCB links significantly
   different from other IEEE 802.11 links.  Any IPv6 mechanism operating
   on IEEE 802.11-OCB link MUST support strong link asymetry, spatio-
   temporal link quality, fast address resolution and transmission.

   IEEE 802.11-OCB strongly differs from other 802.11 systems to operate
   outside of the context of a Basic Service Set.  This means in
   practice that IEEE 802.11-OCB does not rely on a Base Station for all
   Basic Service Set management.  In particular, IEEE 802.11-OCB SHALL
   NOT use beacons.  Any IPv6 mechanism requiring L2 services from IEEE
   802.11 beacons MUST support an alternative service.






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   Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
   implement a mechanism for transmitter and receiver to converge to a
   common channel.

   Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST
   implement an distributed mechanism to authenticate transmitters and
   receivers without the support of a DHCP server.

   Time synchronization not being available, IPv6 over IEEE 802.11-OCB
   MUST implement a higher layer mechanism for time synchronization
   between transmitters and receivers without the support of a NTP
   server.

   The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB
   MUST disable management mechanisms requesting acknowledgements or
   replies.

   The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE
   802.11-OCB MUST implement fast IPv6 mobility management mechanisms.


C.3.  Multiple interfaces


   There are considerations for 2 or more IEEE 802.11-OCB interface
   cards per vehicle.  For each vehicle taking part in road traffic, one
   IEEE 802.11-OCB interface card could be fully allocated for Non IP
   safety-critical communication.  Any other IEEE 802.11-OCB may be used
   for other type of traffic.

   The mode of operation of these other wireless interfaces is not
   clearly defined yet.  One possibility is to consider each card as an
   independent network interface, with a specific MAC Address and a set
   of IPv6 addresses.  Another possibility is to consider the set of
   these wireless interfaces as a single network interface (not
   including the IEEE 802.11-OCB interface used by Non IP safety
   critical communications).  This will require specific logic to
   ensure, for example, that packets meant for a vehicle in front are
   actually sent by the radio in the front, or that multiple copies of
   the same packet received by multiple interfaces are treated as a
   single packet.  Treating each wireless interface as a separate
   network interface pushes such issues to the application layer.

   The privacy requirements of [] imply that if these multiple
   interfaces are represented by many network interface, a single
   renumbering event SHALL cause renumbering of all these interfaces.
   If one MAC changed and another stayed constant, external observers
   would be able to correlate old and new values, and the privacy
   benefits of randomization would be lost.




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   The privacy requirements of Non IP safety-critical communications
   imply that if a change of pseudonyme occurs, renumbering of all other
   interfaces SHALL also occur.


C.4.  MAC Address Generation


   When designing the IPv6 over 802.11-OCB address mapping, we will
   assume that the MAC Addresses will change during well defined
   "renumbering events".  The 48 bits randomized MAC addresses will have
   the following characteristics:

   o  Bit "Local/Global" set to "locally admninistered".

   o  Bit "Unicast/Multicast" set to "Unicast".

   o  46 remaining bits set to a random value, using a random number
      generator that meets the requirements of [RFC4086].

   The way to meet the randomization requirements is to retain 46 bits
   from the output of a strong hash function, such as SHA256, taking as
   input a 256 bit local secret, the "nominal" MAC Address of the
   interface, and a representation of the date and time of the
   renumbering event.


Appendix D.  IEEE 802.11 Messages Transmitted in OCB mode


   For information, at the time of writing, this is the list of IEEE
   802.11 messages that may be transmitted in OCB mode, i.e. when
   dot11OCBActivated is true in a STA:

   o  The STA may send management frames of subtype Action and, if the
      STA maintains a TSF Timer, subtype Timing Advertisement;

   o  The STA may send control frames, except those of subtype PS-Poll,
      CF-End, and CF-End plus CFAck;

   o  The STA may send data frames of subtype Data, Null, QoS Data, and
      QoS Null.

Authors' Addresses



_______________________________________________
its mailing list
its@ietf.org
https://www.ietf.org/mailman/listinfo/its


--_000_D5C97B5122C12Fsgundaveciscocom_
Content-Type: text/html; charset="Windows-1252"
Content-ID: <611201F2DD945649A7EABEAB69DD541D@emea.cisco.com>
Content-Transfer-Encoding: quoted-printable







Agree!







If we look at this work as strictly about transmitting an IPv6 on part=
icular type of link, then its just about defining the mapping of IPv6 addre=
ss to link-layer addresses, and about details on L2 header construction ..e=
tc; more along the lines of RFC2464
 / 6085 ..etc.  We don=92t talk about the operating environment, ND, s=
ecurity, routing ..we only present the relation between L2 and L3 header fi=
elds and stay silent on all other aspects.







But, the issue is when we bring the system level aspects, then we may =
have to state the assumptions as the considerations change based on those a=
ssumptions. For example, if the operating environment is about dynamically =
moving IPv6 nodes (connected over
 802.11-OCB links), which come into proximity for a transient period of tim=
e, then we don=92t know which prefix is routable from which 802.11-OCB peer=
. How does routing/ND work? This is more a MANET problem.  Similarly, =
for other operating environments, there
 may be different set of security, ND, routing and other considerations.&nb=
sp;







The document has to state those assumptions and then present the solut=
ion.












Sri







































From: Russ Housley <housley@vigilsec.com>

Date: Monday, August 28, 2017 at 7:=
06 AM

To: Sri Gundavelli <sgundave@cisco.com>

Cc: "its@ietf.org" <its@ietf.=
org>

Subject: Re: [ipwave] Review commen=
ts on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt












Thanks very much.  These questions make me wonder whether there are di=
fferent answers depending on motion.  If the vehicle is parked, a diff=
erent set of solutions might be desirable.






Russ














On Aug 27, 2017, at 11:00 PM, Sri Gundavelli (sgundave) <=
;sgundave@cisco.com>=
; wrote:













Attached is my review feedback. 







In general there is lot of good information in the document=
. But, there are also few areas where additional clarifications will greatl=
y help.







1.) Its not clear, if the document makes any assumption on =
the operating environment/communication profile. There is not much discussi=
on on that aspect; For example, Is it always a one-hop communication betwee=
n RSU and OBU where the 802.11-OCB
 link?  So, is the use of IPv6 only in that context of 1-hop communica=
tion? 







2.) There is also no discussion on how these links get form=
ed in vehicular environment and when they are attached/detached. 






3.) How do nodes discover each other?  How does ND res=
olution work? Are these messages received by a multiple RSU=92s, or a singl=
e RSU? Whats the implication of that. Note that you don=92t have that issue=
 in 802.11, given the association to an access
 point, which in turn maps the links to a VLAN/subnet.







4.) What happens as a vehicle moves between RSU=92s, how do=
es it impact address configuration?   Is DHCPv6 based address configur=
ation relevant here?












 Please see inline for additional comments.













--------------------=
----------------------------------------------

 
Transmission of IPv6 Packets over IEEE 802.11 Net=
works in mode Outside

        
the Context of a Basic Service Set (IPv6-o=
ver-80211ocb)

              
draft-ietf-ipwave-ipv6-over-80211ocb=
-04.txt






[Sri] May be change to, =93..in mode ..&qu=
ot; =97> =93..oper=
ating in mode ..=94  ?








Abstract

   In order to transmit IPv6 packets on IEEE 802.11 networks run outside
   the context of a basic service set (OCB, earlier "802.11p") th=
ere is
   a need to define a few parameters such as the recommended Maximum
   Transmission Unit size, the header format preceding the IPv6 header,
   the Type value within it, and others.  This document describes these
   parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
   layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
   Ethernet layers - by using an Ethernet Adaptation Layer.



[Sri] Is it =93recommended MTU size",=
 or "supported MTU size on the 802.11 OCB link?  








   In addition, the =
document attempts to list what is different in
   802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
   layers, layers over which IPv6 protocols operates without issues.
   Most notably, the operation outside the context of a BSS (OCB) has
   impact on IPv6 handover behaviour and on IPv6 security.



[Sri] Minor comment. May be instead of usi=
ng the =93layer=94 terminology, you may want to present this as IPv6 suppor=
t on "802.11 OCB" links. 





   An example of an =
IPv6 packet captured while transmitted over an IEEE
   802.11 OCB link (802.11p) is given.



[Sri] Last paragraph can =
be ommitted in my view. That=92s too much of detail for Abstract.





Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of B=
CP 78 and BCP =
79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute



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   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 18, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trus=
tee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . =
. . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . =
. . . . . . . . . . . .   5
   3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    6
   4.  Aspects introduced by the OCB mode to =
802.11  . . . . . . . .   6
   5.  Layering of IPv6 over 802.11-OCB as ov=
er Ethernet . . . . . .  10
     5.1.  Maximum Transmission Unit (MTU) =
. . . . . . . . . . . . .  10
     5.2.  Frame Format  . . . . . . . . . =
. . . . . . . . . . . . .  11
       5.2.1.  Ethernet Adaptation Layer =
. . . . . . . . . . . . . .  12
     5.3.  Link-Local Addresses  . . . . . =
. . . . . . . . . . . . .  13
     5.4.  Address Mapping . . . . . . . . =
. . . . . . . . . . . . .  14
       5.4.1.  Address Mapping -- Unicast=
  . . . . . . . . . . . . .  14
       5.4.2.  Address Mapping -- Multica=
st  . . . . . . . . . . . .  14
     5.5.  Stateless Autoconfiguration . . =
. . . . . . . . . . . . .  15
     5.6.  Subnet Structure  . . . . . . . =
. . . . . . . . . . . . .  16
   6.  Example IPv6 Packet captured over a IE=
EE 802.11-OCB link  . .  16
     6.1.  Capture in Monitor Mode . . . . =
. . . . . . . . . . . . .  17
     6.2.  Capture in Normal Mode  . . . . =
. . . . . . . . . . . . .  19
   7.  Security Considerations . . . . . . . =
. . . . . . . . . . . .  21
   8.  IANA Considerations . . . . . . . . . =
. . . . . . . . . . . .  22
   9.  Contributors  . . . . . . . . . . . . =
. . . . . . . . . . . .  22
   10. Acknowledgements  . . . . . . . . . .=
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   11. References  . . . . . . . . . . . . .=
 . . . . . . . . . . . .  23
     11.1.  Normative References . . . . .=
 . . . . . . . . . . . . .  23
     11.2.  Informative References . . . .=
 . . . . . . . . . . . . .  24
   Appendix A.  ChangeLog  . . . . . . . . .=
 . . . . . . . . . . . .  26
   Appendix B.  Changes Needed on a software=
 driver 802.11a to
                become a                     802.11-OCB driver . . .  28
   Appendix C.  Design Considerations  . . .=
 . . . . . . . . . . . .  30
     C.1.  Vehicle ID  . . . . . . . . . .=
 . . . . . . . . . . . . .  30
     C.2.  Reliability Requirements  . . .=
 . . . . . . . . . . . . .  30
     C.3.  Multiple interfaces . . . . . .=
 . . . . . . . . . . . . .  31
     C.4.  MAC Address Generation  . . . .=
 . . . . . . . . . . . . .  32
   Appendix D.  IEEE 802.11 Messages Transmi=
tted in OCB mode . . . .  32
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  32
1.  Introd=
uction


   This document describes the transmission of IPv6 packets on IEEE Std
   802.11 OCB networks (earlier known as 802.11p).  





[Sri] Please add a reference to the IEEE specification that de=
fines the OCB mode. 








This involves=
 the
   layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with
   an LLC layer).  Compared to running IPv6 over the Ethernet MAC layer,
   there is no modification required to the standards: IPv6 works fine
   directly over 802.11 OCB too (with an LLC layer).

   The term "802.11p" is an earlier definition.  As of year 2012,=
 the
   behaviour of "802.11p" networks has been rolled in the documen=
t IEEE
   Std 802.11-2012.  In this document the term 802.11p disappears.
   Instead, each 802.11p feature is conditioned by a flag in the
   Management Information Base.  That flag is named "OCBActivated"=
;.
   Whenever OCBActivated is set to true the feature it relates to
   represents an earlier 802.11p feature.  For example, an 802.11
   STAtion operating outside the context of a basic service set has the
   OCBActivated flag set.  Such a station, when it has the flag set, it
   uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.

   In the following text we use the term "802.11p" to mean 802.11=
-2012
   OCB.

   The IPv6 network layer operates on 802.11 OCB in the same manner as
   it operates on 802.11 WiFi, with a few particular exceptions.  The
   IPv6 network layer operates on WiFi by involving an Ethernet
   Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers
   to Ethernet II headers.  The operation of IP on Ethernet is described
   in [RFC1042] and [RFC2464].  The situation of IPv6 networking layer
   on Ethernet Adaptation Layer is illustrated below:







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                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+
                 |                 IPv6                  |
                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+
                 |       Ethernet Adaptation Layer       |
                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi MAC           |
                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi PHY           |
                 +-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+


   (in the above figure, a WiFi profile is represented; this is used
   also for OCB profile.)

   A more theoretical and detailed view of layer stacking, and
   interfaces between the IP layer and 802.11 OCB layers, is illustrated
   below.  The IP layer operates on top of the EtherType Protocol
   Discrimination (EPD); this Discrimination layer is described in IEEE
   Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP
   (Link Layer Control Service Accesss Point).


           +-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+
           |                 IPv6                  |
           +-+-+-+-+-+-{            }+-+-&#=
43;-+-+-+-+-+
                       {   LLC_SAP  }                 802.11 OCB
           +-+-+-+-+-+-{            }+-+-&#=
43;-+-+-+-+-+  Boundary
           |            EPD          |       |     |
           |                         | MLME  |     |
           +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   =
|
           |      MAC Sublayer       |       |     |  802.11 OCB
           |     and ch. coord.      |       | SME |  Services
           +-+-+-{   PHY_SAP  }+-+-+-+-+-&#=
43;-+-|     |
           |                         | PLME  |     |
           |            PHY Layer    |   PLME_SAP  |
           +-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+


   In addition to the description of interface between IP and MAC using
   "Ethernet Adaptation Layer" and "Ethernet Protocol Discri=
mination
   (EPD)" it is worth mentioning that SNAP [RFC1042] is used to ca=
rry
   the IPv6 Ethertype.

   However, there may be some deployment considerations helping optimize
   the performances of running IPv6 over 802.11-OCB (e.g. in the case of
   handovers between 802.11 OCB-enabled access routers, or the
   consideration of using the IP security layer [RFC4301]).




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   There are currently no specifications for handover between OCB links
   since these are currently specified as LLC-1 links (i.e.
   connectionless).  Any handovers must be performed above the Data Link
   Layer.  Also, while there is no encryption applied below the network
   layer using 802.11p, 1609.2 [ieee1609.2] does provide security
   services for applications to use so that there can easily be data
   security over the air without invoking IPsec.

   We briefly introduce the vehicular communication scenarios where IEEE
   802.11-OCB links are used. 





[Sri] I have not seen much discussion on the link=
 / communication assumptions. 








 This is foll=
owed by a description of
   differences in specification terms, between 802.11 OCB and
   802.11a/b/g/n (and the same differences expressed in terms of
   requirements to software implementation are listed in Appendix B.)

   The document then concentrates on the parameters of layering IP over
   802.11 OCB as over Ethernet: value of MTU, the contents of Frame
   Format, the rules for forming Interface Identifiers, the mechanism
   for Address Mapping and for State-less Address Auto-configuration.
   These are precisely the same as IPv6 over Ethernet [RFC2464].

   As an example, these characteristics of layering IPv6 straight over
   LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet
   captured over a 802.11 OCB link; this is described in the section
   Section 6.

   A couple of points can be considered as different, although they are
   not required in order to have a working implementation of IPv6-over-
   802.11-OCB.  These points are consequences of the OCB operation which
   is particular to 802.11 OCB (Outside the Context of a BSS).  First,
   the handovers between OCB links need specific behaviour for IP Router
   Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of
   higher layer messages such as the 'Basic Safety Message' (in the US)
   or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE
   Routing Advertisement'; second, the IP security mechanisms are
   necessary, since OCB means that 802.11 is stripped of all 802.11
   link-layer security; a small additional security aspect which is
   shared between 802.11 OCB and other 802.11 links is the privacy
   concerns related to the address formation mechanisms.

   In the published literature, many documents describe aspects related
   to running IPv6 over 802.11 OCB:
   [I-D.je=
ong-ipwave-vehicular-networking-survey].


2.  Terminology


   The key words "MUST", "MUST NOT", "REQUIRED&quo=
t;, "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", &qu=
ot;MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].



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   RSU: Road Side Unit.  A computer equipped with at least one IEEE
   802.11 interface operated in OCB mode.  This definition applies to
   this document.  An RSU may be connected to the Internet, and may be
   equipped with additional wired or wireless network interfaces running
   IP.  An RSU MAY be an IP Router.






[Sri] RSU can be compared to an 802.11 access point; Or, WTP a=
s defined in CAPWAP specification, RFC5415.



Pe=
rhaps. rephrase as below?:





"RSU: Road Side U=
nit. Its a wireless termination point (WTP), as defined in RFC5415 with one=
 key difference, where the wireless physical and the mac l=
ayer is configured to operate in 802.11 OCB mode.  The RSU communicate=
s with the On board Unit (OBU) in the vehicle over 80=
2.11 wireless link operating in OCB mode.=94 








** A=
lso, since you are defining the RSU term, should you also not define OBU (O=
n board Unit) in the vehicle which is the entity on the other end of the li=
nk? =93RSU ----802.11-OCB=97=97OBU=94 ? May be introduce the OCB definition=
 separately, just as you did with RSU, and show the communication link as 8=
02.11-OCB.

=






   OCB: outsi=
de the context of a basic service set (BSS): A mode of
   operation in which a STA is not a member of a BSS and does not
   utilize IEEE Std 802.11 authentication, association, or data
   confidentiality.

   802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is
   flagged by "dot11OCBActivated".  This means: IEEE 802.11e for =
quality
   of service; 802.11j-2004 for half-clocked operations; and (what was
   known earlier as) 802.11p for operation in the 5.9 GHz band and in
   mode OCB.






[Sri] The text starting with. =93This=
 means=94 is not clear to me. Does it 802.11e is supported with 802.11OCB m=
ode. Please clarify






3.  Communication Scenarios where IEEE 802.11 =
OCB Links are Used


   The IEEE 802.11 OCB Networks are used for vehicular communications,
   as 'Wireless Access in Vehicular Environments'.  The IP communication
   scenarios for these environments have been described in several
   documents, among which we refer the reader to one recently updated
   [I-D.petrescu-its-sc=
enarios-reqs], about scenarios and requirements
   for IP in Intelligent Transportation Systems.






[Sri] You can do bit more justice to =
this section. 
Explain the link model. <=
/span> =93STA ----802.11-OCB=97=97STA=94. Then talk ab=
out the applicability in Vehicular networks, with STA's as RSU and OCB.


You may also wa=
nt to talk about, how links get formed/terminated; how nodes peer/discover =
and how mobility works ..etc.  While 802.11-OCB is clearly specified and th=
e use of IPv6 over such link is also not radically new, but the operating e=
nvironment which is vehicular brings many new things. That description is n=
ot present any where.





4.  Aspects introduced by the OCB mode to 802.=
11


   In the IEEE 802.11 OCB mode, all nodes in the wireless range can
   directly communicate with each other without authentication/
   association procedures.  Briefly, the IEEE 802.11 OCB mode has the
   following properties:








[Sri=
] Can you add some text on how nodes (ST1 and STA2) discover each other on =
such links supporting 802.11 OCB mode.


   o  The use=
 by each node of a 'wildcard' BSSID (i.e., each bit of the
      BSSID is set to 1)

   o  No IEEE 802.11 Beacon frames transmitted

   o  No authentication required

   o  No association needed

   o  No encryption provided





<=
span style=3D"font-size: 18px;" class=3D"">[Sri] Can you clarify what you m=
ean when you say =93No xxx required=94 / =93No xxx needed=94  for the a=
bove capabilities.  What does =93needed=94 or =93required=94 mean?  Does it mean, =93Au=
thentication", =93Association" and =93Encryption=94 is optional o=
n this link, or that its not supported on 802.11 OCB links.  





   o  Flag do=
t11OCBActivated set to true

   The following message exchange diagram illustrates a comparison
   between traditional 802.11 and 802.11 in OCB mode.  The 'Data'



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   messages can be IP messages such as the messages used in Stateless or
   Stateful Address Auto-Configuration, or other IP messages.  








[Sri] Lets separate the discussion on IP Add=
ress configuration using SLAAC/DHCP on such links from the above descriptio=
n. The Data packets here can be application packets such as HTTP or other p=
ackets. May be additional discussion is needed on the IP address configurat=
ion on 802.11-OCB links. <=
/pre>








Other
   802.11 management and control frames (non IP) may be transmitted, as
   specified in the 802.11 standard.  For information, the names of
   these messages as currently specified by the 802.11 standard are
   listed in Appendix D.


















     STA     =
               AP              STA1                   STA2
     |                      |               |                      |
     |<------ Beacon -------|               |<------ Data -------->=
;|
     |                      |               |                      |
     |---- Probe Req. ----->|               |<------ Data -------->=
;|
     |<--- Probe Res. ------|               |                      |
     |                      |               |<------ Data -------->|
     |---- Auth Req. ------>|               |                      |
     |<--- Auth Res. -------|               |<------ Data -------->=
;|
     |                      |               |                      |
     |---- Asso Req. ------>|               |<------ Data -------->=
;|
     |<--- Asso Res. -------|               |                      |
     |                      |               |<------ Data -------->|
     |<------ Data -------->|               |                      |
     |<------ Data -------->|               |<------ Data --------=
>|

    (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode


   The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010
   [ieee802.11p-2010] as an amendm=
ent to IEEE Std 802.11 (TM) -2007,
   titled "Amendment 6: Wireless Access in Vehicular Environments"=
;.
   Since then, this amendment has been included in IEEE 802.11(TM)-2012
   [ieee802.11-2012], titled "=
IEEE Standard for Information technology--
   Telecommunications and information exchange between systems Local and
   metropolitan area networks--Specific requirements Part 11: Wireless
   LAN Medium Access Control (MAC) and Physical Layer (PHY)
   Specifications"; the modifications are diffused throughout various
   sections (e.g. the Time Advertisement message described in the
   earlier 802.11 (TM) p amendment is now described in section 'Frame
   formats', and the operation outside the context of a BSS described in
   section 'MLME').

   In document 802.11-2012, specifically anything referring
   "OCBActivated", or "outside the context of a basic servic=
e set" is
   actually referring to the 802.11p aspects introduced to 802.11.  Note
   that in earlier 802.11p documents the term "OCBEnabled" was us=
ed
   instead of te current "OCBActivated".





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   In order to delineate the aspects introduced by 802.11 OCB to 802.11,
   we refer to the earlier [ieee802.11=
p-2010].  The amendment is
   concerned with vehicular communications, where the wireless link is
   similar to that of Wireless LAN (using a PHY layer specified by
   802.11a/b/g/n), but which needs to cope with the high mobility factor
   inherent in scenarios of communications between moving vehicles, and
   between vehicles and fixed infrastructure deployed along roads.
   While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is
   concerned more with MAC modifications, and a little with PHY
   modifications; the others are mainly about PHY modifications.  It is
   possible in practice to combine a 'p' MAC with an 'a' PHY by
   operating outside the context of a BSS with OFDM at 5.4GHz.

   The 802.11 OCB links are specified to be compatible as much as
   possible with the behaviour of 802.11a/b/g/n and future generation
   IEEE WLAN links.  From the IP perspective, an 802.11 OCB M=
AC layer
   offers practically the same interface to IP as the WiFi and Ethernet
   layers do (802.11a/b/g/n and 802.3).





[Sri] A packet sent from a vehicle=92s OBU is rec=
eived by a single RSU, or multiple RSU=92s? How does the link-layer resolut=
ion happen?





   To support=
 this similarity statement (IPv6 is layered on top of LLC
   on top of 802.11 OCB similarly as on top of LLC on top of
   802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to
   analyze the differences between 802.11 OCB and 802.11 specifications.
   Whereas the 802.11p amendment specifies relatively complex and
   numerous changes to the MAC layer (and very little to the PHY layer),
   we note there are only a few characteristics which may be important
   for an implementation transmitting IPv6 packets on 802.11 OCB links.

   In the list below, the only 802.11 OCB fundamental points which
   influence IPv6 are the OCB operation and the 12Mbit/s maximum which
   may be afforded by the IPv6 applications.






<=
span style=3D"font-size: 18px;" class=3D"">[Sri] I am really not sure how l=
ink throughput (12Mbps) relates to "IPv6 support on OCB links".  =









   o  Operati=
on Outside the Context of a BSS (OCB): the (earlier
      802.11p) 802.11-OCB links are operated without a Basic Service Set
      (BSS).  This means that the frames IEEE 802.11 Beacon, Association
      Request/Response, Authentication Request/Response, and similar,
      are not used.  The used identifier of BSS (BSSID) has a
      hexadecimal value always 0xffffffffffff (48 '1' bits, represented
      as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'
      BSSID), as opposed to an arbitrary BSSID value set by
      administrator (e.g.  'My-Home-AccessPoint').  The OCB operation -
      namely the lack of beacon-based scanning and lack of
      authentication - has a potentially strong impact on the use of the
      Mobile IPv6 protocol [RFC62=
75] and on the protocols for IP layer
      security [RFC4301].






<=
span style=3D"font-size: 18px;" class=3D"">[Sri] The document till now has =
been arguing heavily on how IPv6 operates so naturally on these links and n=
ow I see discussion on =93Impact to a high-level protocol such as MIPv6=94. You may want to fix the earlier text. In a=
ny case,  the absence of link-layer security practically impacts every appl=
ication, not just MIPv6.  Also, MIPv6 does not make any assumptions on the =
link-layer security.  Also, the the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes=
 the messages readable by all other RSU=92s in proximity. I think the discu=
ssion on the nature of the link, who all see=92s the messages.. how L2 addr=
esses are resolved is not explained clearly. 











   o  Timing =
Advertisement: is a new message defined in 802.11-OCB,
      which does not exist in 802.11a/b/g/n.  This message is used by



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      stations to inform other stations about the value of time.  It is
      similar to the time as delivered by a GNSS system (Galileo, GPS,
      ...) or by a cellular system.  This message is optional for
      implementation.  At the date of writing, an experienced=
 reviewer
      considers that currently no field testing has used this message.
      Another implementor considers this feature implemented in an
      initial manner.  In the future, it is speculated that this message
      may be useful for very simple devices which may not have their own
      hardware source of time (Galileo, GPS, cellular network), or by
      vehicular devices situated in areas not covered by such network
      (in tunnels, underground, outdoors but shaded by foliage or
      buildings, in remote areas, etc.)






[Sri] The first part explaining Timin=
g Advertisement messages is great, but the rest of the commentary is unnece=
ssary and not needed. We don=92t speculate the protocol adoption success in=
 IETF specifications, or about the experience level of the =93reviewer"=
; :)








   o  Frequen=
cy range: this is a characteristic of the PHY layer, with
      almost no impact to the interface between MAC and IP.  However, it
      is worth considering that the frequency range is regulated by a
      regional authority (ARCEP, ETSI, FCC, etc.); as part of the
      regulation process, specific applications are associated with
      specific frequency ranges.  In the case of 802.11-OCB, the
      regulator associates a set of frequency ranges, or slots within a
      band, to the use of applications of vehicular communications, in a
      band known as "5.9GHz".  This band is "5.9GHz" wh=
ich is different
      from the bands "2.4GHz" or "5GHz" used by Wireles=
s LAN.  However,
      as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz&quo=
t;
      bands is exempt from owning a license in EU (in US the 5.9GHz is a
      licensed band of spectrum; for the the fixed infrastructure an
      explicit FCC autorization is required; for an onboard device a
      'licensed-by-rule' concept applies: rule certification conformity
      is required); however technical conditions are different than
      those of the bands "2.4GHz" or "5GHz".  On one ha=
nd, the allowed
      power levels, and implicitly the maximum allowed distance between
      vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20
      dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum
      distance of approximately 1km, compared to approximately 50m.  On
      the other hand, specific conditions related to congestion
      avoidance, jamming avoidance, and radar detection are imposed on
      the use of DSRC (in US) and on the use of frequencies for
      Intelligent Transportation Systems (in EU), compared to Wireless
      LAN (802.11a/b/g/n).

   o  Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB,
      as opposed to IPv6 not being prohibited on any channel on which
      802.11a/b/g/n runs:

      *  Some channels are reserved for safety communications; the IPv6
         packets should not be sent on these channels.





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      *  At the time of writing, the prohibition is explicit at higher
         layer protocols providing services to the application; these
         higher layer protocols are specified in IEEE 1609 documents.

      *  National or regional specifications and regulations specify the
         use of different channels; these regulations must be followed.

   o  'Half-rate' encoding: as the frequency range, this parameter is
      related to PHY, and thus has not much impact on the interface
      between the IP layer and the MAC layer.

   o  In vehicular communications using 802.11-OCB links, there are
      strong privacy requirements with respect to addressing.  While the
      802.11-OCB standard does not specify anything in particular with
      respect to MAC addresses, in these settings there exists a strong
      need for dynamic change of these addresses (as opposed to the non-
      vehicular settings - real wall protection - where fixed MAC
      addresses do not currently pose some privacy risks).  This is
      further described in section Section 7.=
  A relevant function is
      described in IEEE 1609.3-2016 [ieee160=
9.3], clause 5.5.1 and IEEE
      1609.4-2016 [ieee1609.4], clause 6=
.7.






   Other aspe=
cts particular to 802.11-OCB which are also particular to
   802.11 (e.g. the 'hidden node' operation) may have an influence on
   the use of transmission of IPv6 packets on 802.11-OCB networks.  The
   subnet structure which may be assumed in 802.11-OCB networks is
   strongly influenced by the mobility of vehicles.





[Sri] Per my earlier comment, the lin=
k model, addressing ..etc needs to be explained in more detail. It is not c=
lear what exactly the =93subnet structure=94 that is assumed in 802.11-OCB.=






5.  Layering of IPv6 over 802.11-OCB as over E=
thernet
5.1.  Maximu=
m Transmission Unit (MTU)


   The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is
   the same value as IPv6 packets on Ethernet links, as specified in
   [RFC2464].=
  This value of the MTU respects the recommendation that
   every link in the Internet must have a minimum MTU of 1280 octets
   (stated in [RFC2=
460], and the recommendations therein, especially
   with respect to fragmentation).  If IPv6 packets of size larger than
   1500 bytes are sent on an 802.11-OCB interface card then the IP stack
   will fragment.  In case there are IP fragments, the field "Sequence
   number" of the 802.11 Data header containing the IP fragment field =
is
   increased.

   Non-IP packets such as WAVE Short Message Protocol (WSMP) can be
   delivered on 802.11-OCB links.  Specifications of these packets are
   out of scope of this document, and do not impose any limit on the MTU
   size, allowing an arbitrary number of 'containers'.  Non-IP packets
   such as ETSI 'geonet' packets have an MTU of 1492 bytes.



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   The Equivalent Transmit Time on Channel is a concept that may be used
   as an alternative to the MTU concept.  A rate of transmission may be
   specified as well.  The ETTC, rate and MTU may be in direct
   relationship.



[Sri] The last paragraph needs some a=
dditional context. Did 802.11-OCB introduce ETTC concept?  











5.2.  Frame Format


   IP packets are transmitted over 802.11-OCB as standard Ethernet
   packets.  As with all 802.11 frames, an Ethernet adaptation layer is
   used with 802.11-OCB as well.  This Ethernet Adaptation Layer
   performing 802.11-to-Ethernet is described in Section 5.2.1.  The
   Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD,
   or otherwise #86DD).

   The Frame format for transmitting IPv6 on 802.11-OCB networks is the
   same as transmitting IPv6 on Ethernet networks, and is described in
   sec=
tion 3 of [RFC2464].  The frame format for transmitting IPv6
   packets over Ethernet is illustrated below:


                    0                   1
                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    |          Destination          |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    |             Source            |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    |             IPv6              |
                    +-                             -+
                    |            header             |
                    +-                             -+
                    |             and               |
                    +-                             -+
                    /            payload ...        /
                    +-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+
                    (Each tic mark represents one bit.)





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   Ethernet II Fields:

   Destination Ethernet Address
      the MAC destination address.

   Source Ethernet Address
      the MAC source address.

   1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
      binary representation of the EtherType value 0x86DD.

   IPv6 header and payload
      the IPv6 packet containing IPv6 header and payload.


5.2.1.  Ethernet Adaptatio=
n Layer


   In general, an 'adaptation' layer is inserted between a MAC layer and
   the Networking layer.  This is used to transform some parameters
   between their form expected by the IP stack and the form provided by
   the MAC layer.  For example, an 802.15.4 adaptation layer may perform
   fragmentation and reassembly operations on a MAC whose maximum Packet
   Data Unit size is smaller than the minimum MTU recognized by the IPv6
   Networking layer.  Other examples involve link-layer address
   transformation, packet header insertion/removal, and so on.

   An Ethernet Adaptation Layer makes an 802.11 MAC look to IP
   Networking layer as a more traditional Ethernet layer.  At reception,
   this layer takes as input the IEEE 802.11 Data Header and the
   Logical-Link Layer Control Header and produces an Ethernet II Header.
   At sending, the reverse operation is performed.


 +--------------------+------------+-------------+---------=
+-----------+
 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer|
 +--------------------+------------+-------------+---------=
+-----------+
  \                               /                         \         /
    -----------------------------                             --------
                   ^---------------------------------------------/
                   |
           802.11-to-Ethernet Adaptation Layer
                   |
                   v
 +---------------------+-------------+---------+
 | Ethernet II Header  | IPv6 Header | Payload |
 +---------------------+-------------+---------+






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   The Receiver and Transmitter Address fields in the 802.11 Data Header
   contain the same values as the Destination and the Source Address
   fields in the Ethernet II Header, respectively.  The value of the
   Type field in the LLC Header is the same as the value of the Type
   field in the Ethernet II Header.

   The ".11 Trailer" contains solely a 4-byte Frame Check Sequenc=
e.

   The Ethernet Adaptation Layer performs operations in relation to IP
   fragmentation and MTU.  One of these operations is briefly described
   in section Section 5.1.

   In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11
   Data" or alternatively as "IEEE 802.11 QoS Data", as illu=
strated in
   the following figure:


+--------------------+-------------+-------------+---------=
+-----------+
| 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------=
+-----------+

or

+--------------------+-------------+-------------+---------=
+-----------+
| 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------=
+-----------+


   The distinction between the two formats is given by the value of the
   field "Type/Subtype".  The value of the field "Type/Subty=
pe" in the
   802.11 Data header is 0x0020.  The value of the field "Type/Subtype=
"
   in the 802.11 QoS header is 0x0028.

   The mapping between qos-related fields in the IPv6 header (e.g.
   "Traffic Class", "Flow label") and fields in the &qu=
ot;802.11 QoS Data
   Header" (e.g.  "QoS Control") are not specified in this d=
ocument.
   Guidance for a potential mapping is provided in
   [I-D.ietf-tsvwg-ieee-802-=
11], although it is not specific to OCB
   mode.









[Sri] The applicability of the QoS ma=
pping draft to 802.11-OCB needs further investigation, IMO.











5.3.  Link-Local Addresses


   The link-local address of an 802.11-OCB interface is formed in the
   same manner as on an Ethernet interface.  This manner is described in
   sec=
tion 5 of [RFC2464].





[Sri=
] Does this go against the 8064 recommendation on Interface identifier gene=
ration?
May be RFC7217 for interface identifier=
 generation in conjunction with the link-local address generation per RFC24=
64

<=
/font>
Petre=
scu, et al.        Expires February 18, 2018              [Page 13]<=
/pre>



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5.4.  Address M=
apping


   For unicast as for multicast, there is no change from the unicast and
   multicast address mapping format of Ethernet interfaces, as defined
   by sections 6 and 7 of [RFC24=
64].









[Sri] RFC6085 specified mapping is also re=
levant; If the communication peers are aware that there is only one peer, i=
t should apply 6085 specified mapping. That mode is relevant for 802.11-OCB=
 types links as well.








5.4.1.  Address Mapping -- Unicast

   The procedure for mapping IPv6 unicast addresses into Ethernet link-
   layer addresses is described in [RFC4861].  The Source/Target Link-
   layer Address option has the following form when the link-layer is
   Ethernet.



[Sri] I thought, mapping of IPv6 unic=
ast addresses to Ethernet link-layer addresses is specified in section 6, o=
f RFC2464 and not in RFC4861.











             =
         0                   1
                      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+
                     |     Type      |    Length     |
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+
                     |                               |
                     +-          Ethernet           -+
                     |                               |
                     +-           Address           -+
                     |                               |
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+


   Option fields:

   Type
      1 for Source Link-layer address.
      2 for Target Link-layer address.

   Length
      1 (in units of 8 octets).

   Ethernet Address
      The 48 bit Ethernet IEEE 802 address, in canonical bit order.


5.4.2.  Address Mapping --=
 Multicast


   IPv6 protocols often make use of IPv6 multicast addresses in the
   destination field of IPv6 headers.  For example, an ICMPv6 link-
   scoped Neighbor Advertisement is sent to the IPv6 address ff02::1
   denoted "all-nodes" address.  When transmitting these packets =
on
   802.11-OCB links it is necessary to map the IPv6 address to a MAC
   address.




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   The same mapping requirement applies to the link-scoped multicast
   addresses of other IPv6 protocols as well.  In DHCPv6, the
   "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OS=
PF the
   "All_SPF_Routers" IPv6 multicast address ff02::5, need to be m=
apped
   on a multicast MAC address.

   An IPv6 packet with a multicast destination address DST, consisting
   of the sixteen octets DST[1] through DST[16], is transmitted to the
   IEEE 802.11-OCB MAC multicast address whose first two octets are the
   value 0x3333 and whose last four octets are the last four octets of
   DST.



<=
font face=3D"Calibri,sans-serif" class=3D"">[Sri] Please add a reference to Section 7, RFC4861 and also RF=
C6085. In general, for both unicast and multicast, you may want to clearly =
say that this is per the existing specs and duplicated here for convenience=
. 





             =
        +-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+
                     |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+
                     |   DST[13]     |   DST[14]     |
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+
                     |   DST[15]     |   DST[16]     |
                     +-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+


   A Group ID TBD of length 112bits may be requested from IANA; this
   Group ID signifies "All 80211OCB Interfaces Address".  Only th=
e least
   32 significant bits of this "All 80211OCB Interfaces Address" =
will be
   mapped to and from a MAC multicast address.

   Transmitting IPv6 packets to multicast destinations over 802.11 links
   proved to have some performance issues
   [I-D.perkins-i=
ntarea-multicast-ieee802].  These issues may be
   exacerbated in OCB mode.  Solutions for these problems should
   consider the OCB mode of operation.


5.5.  Stateless Autoconfigurati=
on


   The Interface Identifier for an 802.11-OCB interface is formed using
   the same rules as the Interface Identifier for an Ethernet interface;
   this is described in section 4 of [RFC2464].  No changes are needed,
   but some care must be taken when considering the use of the SLAAC
   procedure.








[Sri] Per my earlier comment, please =
refer to the current recommendation on interface-identifier generation and =
its use in link-local, global or other addresses.


   The bits in the the interface identifier have no generic meaning and
   the identifier should be treated as an opaque value.  The bits
   'Universal' and 'Group' in the identifier of an 802.11-OCB interface
   are significant, as this is an IEEE link-layer address.  The details
   of this significance are described in [I-D.ietf-6man-ug<=
font face=3D"Calibri,sans-serif" size=3D"3" class=3D"">].





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   As with all Ethernet and 802.11 interface identifiers ([RFC7721]),
   the identifier of an 802.11-OCB interface may involve privacy risks.
   A vehicle embarking an On-Board Unit whose egress interface is
   802.11-OCB may expose itself to eavesdropping and subsequent
   correlation of data; this may reveal data considered private by the
   vehicle owner; there is a risk of being tracked; see the privacy
   considerations described in Appendix C.






<=
font face=3D"Calibri,sans-serif" class=3D"">[Sri] I think there are other security issues here; the absenc=
e of link-layer security opens up Mac-spoofing and IP address hijacking.  T=
hat should be mentioned.






   If stable =
Interface Identifiers are needed in order to form IPv6
   addresses on 802.11-OCB links, it is recommended to follow the
   recommendation in [I-D.ie=
tf-6man-default-iids].


5.6.  Subnet Structure


   The 802.11 networks in OCB mode may be considered as 'ad-hoc'
   networks.  The addressing model for such networks is described in
   [RFC5889].






[Sri] Per my earlier comment, there i=
s no system level view of the network where 802.11-OCB links are used. So, =
in the absence of such discussion So, I am not =
sure what part of RFC5889 is applicable here. For example, link-local addresses may just work fine. 








6.  Example IPv6 Packet captured over a IEEE 8=
02.11-OCB link


   We remind that a main goal of this document is to make the case that
   IPv6 works fine over 802.11-OCB networks.  Consequently, this section
   is an illustration of this concept and thus can help the implementer
   when it comes to running IPv6 over IEEE 802.11-OCB.  By way of
   example we show that there is no modification in the headers when
   transmitted over 802.11-OCB networks - they are transmitted like any
   other 802.11 and Ethernet packets.

   We describe an experiment of capturing an IPv6 packet on an
   802.11-OCB link.  In this experiment, the packet is an IPv6 Router
   Advertisement.  This packet is emitted by a Router on its 802.11-OCB
   interface.  The packet is captured on the Host, using a network
   protocol analyzer (e.g.  Wireshark); the capture is performed in two
   different modes: direct mode and 'monitor' mode.  The topology used
   during the capture is depicted below.


              +--------+                                +------=
-+
              |        |        802.11-OCB Link         |       |
           ---| Router |--------------------------------| Host  |
              |        |                                |       |
              +--------+                                +------=
-+


   During several capture operations running from a few moments to
   several hours, no message relevant to the BSSID contexts were
   captured (no Association Request/Response, Authentication Req/Resp,




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   Beacon).  This shows that the operation of 802.11-OCB is outside the
   context of a BSSID.

   Overall, the captured message is identical with a capture of an IPv6
   packet emitted on a 802.11b interface.  The contents are precisely
   similar.






[Sri] I suggest moving this discussio=
n under the section =93Implementation Status=94, which will eventually be r=
emoved from the RFC. There is nothing new here. This are details on experim=
entation. But, if you think there is some useful information  such as discu=
ssion on Capture mode ..etc, you may want to move this entire section to Ap=
pendix. Implementors may use these tools for verification.











6.1.  Capture in Monitor Mode


   The IPv6 RA packet captured in monitor mode is illustrated below.
   The radio tap header provides more flexibility for reporting the
   characteristics of frames.  The Radiotap Header is prepended by this
   particular stack and operating system on the Host machine to the RA
   packet received from the network (the Radiotap Header is not present
   on the air).  The implementation-dependent Radiotap Header is useful
   for piggybacking PHY information from the chip's registers as data in
   a packet understandable by userland applications using Socket
   interfaces (the PHY interface can be, for example: power levels, data
   rate, ratio of signal to noise).

   The packet present on the air is formed by IEEE 802.11 Data Header,
   Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.



     Radiotap Header v0
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |Header Revision|  Header Pad   |    Header length              |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                         Present flags                         |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     | Data Rate     |             Pad                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+

     IEEE 802.11 Data Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |  Type/Subtype and Frame Ctrl  |          Duration             |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                      Receiver Address...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ... Receiver Address           |      Transmitter Address...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ... Transmitter Address                                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                            BSS Id...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ... BSS Id                     |  Frag Number and Seq Number   |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+



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     Logical-Link Control Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |      DSAP   |I|     SSAP    |C| Control field | Org. code...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ... Organizational Code        |             Type              |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +                         Source Address                        &#=
43;
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +                      Destination Address                      &#=
43;
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-


   The value of the Data Rate field in the Radiotap header is set to 6
   Mb/s.  This indicates the rate at which this RA was received.





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   The value of the Transmitter address in the IEEE 802.11 Data Header
   is set to a 48bit value.  The value of the destination address is
   33:33:00:00:00:1 (all-nodes multicast address).  The value of the BSS
   Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network
   protocol analyzer as being "broadcast".  The Fragment number a=
nd
   sequence number fields are together set to 0x90C6.

   The value of the Organization Code field in the Logical-Link Control
   Header is set to 0x0, recognized as "Encapsulated Ethernet".  =
The
   value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise
   #86DD), recognized as "IPv6".

   A Router Advertisement is periodically sent by the router to
   multicast group address ff02::1.  It is an icmp packet type 134.  The
   IPv6 Neighbor Discovery's Router Advertisement message contains an
   8-bit field reserved for single-bit flags, as described in [RFC4861].

   The IPv6 header contains the link local address of the router
   (source) configured via EUI-64 algorithm, and destination address set
   to ff02::1.  Recent versions of network protocol analyzers (e.g.
   Wireshark) provide additional informations for an IP address, if a
   geolocalization database is present.  In this example, the
   geolocalization database is absent, and the "GeoIP" informatio=
n is
   set to unknown for both source and destination addresses (although
   the IPv6 source and destination addresses are set to useful values).
   This "GeoIP" can be a useful information to look up the city,
   country, AS number, and other information for an IP address.





[Sri] Not sure, why all of this text should be in the specificatio=
n. 





   The Ethern=
et Type field in the logical-link control header is set to
   0x86dd which indicates that the frame transports an IPv6 packet.  In
   the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
   which is he corresponding multicast MAC address.  The BSS id is a
   broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link
   duration between vehicles and the roadside infrastructure, there is
   no need in IEEE 802.11-OCB to wait for the completion of association
   and authentication procedures before exchanging data.  IEEE
   802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)
   and may start communicating as soon as they arrive on the
   communication channel.


6.2.  Capture in Normal Mode

   The same IPv6 Router Advertisement packet described above (monitor
   mode) is captured on the Host, in the Normal mode, and depicted
   below.






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     Ethernet II Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                       Destination...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ...Destination                 |           Source...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     ...Source                                                      |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |          Type                 |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +                         Source Address                        &#=
43;
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +                      Destination Address                      &#=
43;
     |                                                               |
     +                                                               &#=
43;
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+=
;-+-+-+-+-+-+-+-+-+-+-+-+-&=
#43;-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+=
;-





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   One notices that the Radiotap Header is not prepended, and that the
   IEEE 802.11 Data Header and the Logical-Link Control Headers are not
   present.  On another hand, a new header named Ethernet II Header is
   present.

   The Destination and Source addresses in the Ethernet II header
   contain the same values as the fields Receiver Address and
   Transmitter Address present in the IEEE 802.11 Data Header in the
   "monitor" mode capture.

   The value of the Type field in the Ethernet II header is 0x86DD
   (recognized as "IPv6"); this value is the same value as the va=
lue of
   the field Type in the Logical-Link Control Header in the "monitor&q=
uot;
   mode capture.

   The knowledgeable experimenter will no doubt notice the similarity of
   this Ethernet II Header with a capture in normal mode on a pure
   Ethernet cable interface.

   It may be interpreted that an Adaptation layer is inserted in a pure
   IEEE 802.11 MAC packets in the air, before delivering to the
   applications.  In detail, this adaptation layer may consist in
   elimination of the Radiotap, 802.11 and LLC headers and insertion of
   the Ethernet II header.  In this way, it can be stated that IPv6 runs
   naturally straight over LLC over the 802.11-OCB MAC layer, as shown
   by the use of the Type 0x86DD, and assuming an adaptation layer
   (adapting 802.11 LLC/MAC to Ethernet II header).


7.  Security Considerations


   Any security mechanism at the IP layer or above that may be carried
   out for the general case of IPv6 may also be carried out for IPv6
   operating over 802.11-OCB.






   802.11-OCB=
 does not provide any cryptographic protection, because it
   operates outside the context of a BSS (no Association Request/
   Response, no Challenge messages).  Any attacker can therefore just
   sit in the near range of vehicles, sniff the network (just set the
   interface card's frequency to the proper range) and perform attacks
   without needing to physically break any wall.  Such a link is way
   less protected than commonly used links (wired link or protected
   802.11).



[Sri=
] Per my earlier comment, there is more than one attack vector possible
1.) Absence of link-layer security and the potenti=
al for mac address spoofing 
2.) IP address / S=
ession hijacking 
3.) Dat=
a privacy per your text






   At the IP =
layer, IPsec can be used to protect unicast communications,
   and SeND can be used for multicast communications. 





[Sri] IPSec can be used for protecting both multicast or unicast c=
ommunication; RFC-5374 with GDOI.











 If no protec=
tion
   is used by the IP layer, upper layers should be protected.
   Otherwise, the end-user or system should be warned about the risks
   they run.



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   As with all Ethernet and 802.11 interface identifiers, there may
   exist privacy risks in the use of 802.11-OCB interface identifiers.
   Moreover, in outdoors vehicular settings, the privacy risks are more
   important than in indoors settings.  New risks are induced by the
   possibility of attacker sniffers deployed along routes which listen
   for IP packets of vehicles passing by.  For this reason, in the
   802.11-OCB deployments, there is a strong necessity to use protection
   tools such as dynamically changing MAC addresses.  This may help
   mitigate privacy risks to a certain level.  On another hand, it may
   have an impact in the way typical IPv6 address auto-configuration is
   performed for vehicles (SLAAC would rely on MAC addresses amd would
   hence dynamically change the affected IP address), in the way the
   IPv6 Privacy addresses were used, and other effects.


8.  IANA Considerations
=

9.  Contributors


   Romain Kuntz contributed extensively about IPv6 handovers between
   links running outside the context of a BSS (802.11-OCB links).

   Tim Leinmueller contributed the idea of the use of IPv6 over
   802.11-OCB for distribution of certificates.

   Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey
   Voronov provided significant feedback on the experience of using IP
   messages over 802.11-OCB in initial trials.

   Michelle Wetterwald contributed extensively the MTU discussion,
   offered the ETSI ITS perspective, and reviewed other parts of the
   document.


10.  Acknowledgements


   The authors would like to thank Witold Klaudel, Ryuji Wakikawa,
   Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan
   Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray
   Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,
   Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,
   Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,
   Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and
   William Whyte.  Their valuable comments clarified certain issues and
   generally helped to improve the document.

   Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB
   drivers for linux and described how.





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   For the multicast discussion, the authors would like to thank Owen
   DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and
   participants to discussions in network working groups.

   The authours would like to thank participants to the Birds-of-
   a-Feather "Intelligent Transportation Systems" meetings held a=
t IETF
   in 2016.


11.  References
11.1.  Normative References


   [I-D.ietf-6man-default-iids]
              Gont, F., Cooper, A., Thaler, D., and S. LIU,
              "Recommendation on Stable IPv6 Interface Identifiers&quo=
t;,
              draft-ietf-6man-default-iids-16 (work in progress=
),
              September 2016.

   [I-D.ietf-6man-ug]
              Carpenter, B. and S. Jiang, "Significance of IPv6
              Interface Identifiers", draft-ietf-6man-ug-06 (work in
              progress), December 2013.

   [I-D.ietf-tsvwg-ieee-802-11]
              Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE
              802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-06=
 (work in
              progress), August 2017.

   [RFC1042]  Pos=
tel, J. and J. Reynolds, "Standard for the transmission
              of IP datagrams over IEEE 802 networks", STD 43, RFC 1042,
              DOI 10.17487/RFC1042, February 1988, <https://www.rfc-
              editor.org/info/rfc1042>.

   [RFC2119]  Bra=
dner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997, <https://www.rfc-
              editor.org/info/rfc2119>.

   [RFC2460]  Dee=
ring, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
              December 1998, <https://www.rfc-editor.org/info/rfc2460>.

   [RFC2464]  Cra=
wford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998,
              <https://www.rfc-editor.org/info/rfc2464>.






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   [RFC3963]  Dev=
arapalli, V., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol=
",
              RF=
C 3963, DOI 10.17487/RFC3963, January 2005,
              <https://www.rfc-editor.org/info/rfc3963>.

   [RFC4086]  Eas=
tlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security", BCP 106, RFC 4086,
              DOI 10.17487/RFC4086, June 2005, <https://www.rfc-
              editor.org/info/rfc4086>.

   [RFC4301]  Ken=
t, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.

   [RFC4429]  Moo=
re, N., "Optimistic Duplicate Address Detection (DAD)
              for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006,
              <https://www.rfc-editor.org/info/rfc4429>.

   [RFC4861]  Nar=
ten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007, <https://www.rfc-
              editor.org/info/rfc4861>.

   [RFC5889]  Bac=
celli, E., Ed. and M. Townsley, Ed., "IP Addressing
              Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889,
              September 2010, <https://www.rfc-editor.org/info/rfc5889>.

   [RFC6275]  Per=
kins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
              2011, <https://www.rfc-editor.org/info/rfc6275>.

   [RFC6775]  She=
lby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
              Bormann, "Neighbor Discovery Optimization for IPv6 over
              Low-Power Wireless Personal Area Networks (6LoWPANs)",
              RF=
C 6775, DOI 10.17487/RFC6775, November 2012,
              <https://www.rfc-editor.org/info/rfc6775>.

   [RFC7721]  Coo=
per, A., Gont, F., and D. Thaler, "Security and Privacy
              Considerations for IPv6 Address Generation Mechanisms",
              RF=
C 7721, DOI 10.17487/RFC7721, March 2016,
              <https://www.rfc-editor.org/info/rfc7721>.


11.2.  Informative Referenc=
es
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   [fcc-cc]   "=
;'Report and Order, Before the Federal Communications
              Commission Washington, D.C. 20554', FCC 03-324, Released
              on February 10, 2004, document FCC-03-324A1.pdf, document
              freely available at URL
              http://www.its.dot.gov/exit/fcc_edocs.htm downloaded on
              October 17th, 2013.".

   [fcc=
-cc-172-184]
              "'Memorandum Opinion and Order, Before the Federal
              Communications Commission Washington, D.C. 20554', FCC
              06-10, Released on July 26, 2006, document FCC-
              06-110A1.pdf, document freely available at URL
              http://hraunfoss.fcc.gov/edocs_public/attachma=
tch/
              FCC-06-110A1.pdf downloaded on June 5th, 2=
014.".

   [I-D.jeong-ipwave-v=
ehicular-networking-survey]
              Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M.
              Wetterwald, "Survey on IP-based Vehicular Networking for
              Intelligent Transportation Systems", draft-jeong-ipwave-
              vehicular-networking-survey-03 =
(work in progress), June
              2017.

   [I-D.perkins-intarea-multicast-ie=
ee802]
              Perkins, C., Stanley, D., Kumari, W., and J. Zuniga,
              "Multicast Considerations over IEEE 802 Wireless Media&q=
uot;,
              draft-perkins-intarea-multicast-ieee802-03=
 (work in
              progress), July 2017.

   [I-D.petrescu-its-scenarios-reqs]
              Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel,
              "Scenarios and Requirements for IP in Intelligent
              Transportation Systems", draft-petrescu-its=
-scenarios-
              reqs-03 (work in progress), October 2013.

   [ieee1609.2<=
/a>]
              "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Acce=
ss
              in Vehicular Environments (WAVE) -- Security Services for
              Applications and Management Messages.  Example URL
              http://ieeexplore.ieee.org/document/7426684/ accessed on
              August 17th, 2017.".

   [ieee1609.3<=
/a>]
              "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Acce=
ss
              in Vehicular Environments (WAVE) -- Networking Services.
              Example URL http://ieeexplore.ieee.org/document/7458115/
              accessed on August 17th, 2017.".





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   [ieee1609.4<=
/a>]
              "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Acce=
ss
              in Vehicular Environments (WAVE) -- Multi-Channel
              Operation.  Example URL
              http://ieeexplore.ieee.org/document/7435228/ accessed on
              August 17th, 2017.".

   [i=
eee802.11-2012]
              "802.11-2012 - IEEE Standard for Information technology-=
-
              Telecommunications and information exchange between
              systems Local and metropolitan area networks--Specific
              requirements Part 11: Wireless LAN Medium Access Control
              (MAC) and Physical Layer (PHY) Specifications.  Downloaded
              on October 17th, 2013, from IEEE Standards, document
              freely available at URL
              http://standards.ieee.org/findstds/
              standard/802.11-2012.html retrieved on October 1=
7th,
              2013.".

   [ieee802.11p-2010]
              "IEEE Std 802.11p (TM)-2010, IEEE Standard for Informati=
on
              Technology - Telecommunications and information exchange
              between systems - Local and metropolitan area networks -
              Specific requirements, Part 11: Wireless LAN Medium Access
              Control (MAC) and Physical Layer (PHY) Specifications,
              Amendment 6: Wireless Access in Vehicular Environments;
              document freely available at URL
              http://standards.ieee.org/getieee802/
              download/802.11p-2010.pdf retrieved on Septemb=
er 20th,
              2013.".


Appendix A.  ChangeLog


   The changes are listed in reverse chronological order, most recent
   changes appearing at the top of the list.

   From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave-
   ipv6-over-80211ocb-04

   o  Removed a few informative references pointing to Dx draft IEEE
      1609 documents.

   o  Removed outdated informative references to ETSI documents.

   o  Added citations to IEEE 1609.2, .3 and .4-2016.

   o  Minor textual issues.




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   From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave-
   ipv6-over-80211ocb-03

   o  Keep the previous text on multiple addresses, so remove talk about
      MIP6, NEMOv6 and MCoA.

   o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.

   o  Clarified the figure showing Infrastructure mode and OCB mode side
      by side.

   o  Added a reference to the IP Security Architecture RFC.

   o  Detailed the IPv6-per-channel prohibition paragraph which reflects
      the discussion at the last IETF IPWAVE WG meeting.

   o  Added section "Address Mapping -- Unicast".

   o  Added the ".11 Trailer" to pictures of 802.11 frames.

   o  Added text about SNAP carrying the Ethertype.

   o  New RSU definition allowing for it be both a Router and not
      necessarily a Router some times.

   o  Minor textual issues.

   From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave-
   ipv6-over-80211ocb-02

   o  Replaced almost all occurences of 802.11p with 802.11-OCB, leaving
      only when explanation of evolution was necessary.

   o  Shortened by removing parameter details from a paragraph in the
      Introduction.

   o  Moved a reference from Normative to Informative.

   o  Added text in intro clarifying there is no handover spec at IEEE,
      and that 1609.2 does provide security services.

   o  Named the contents the fields of the EthernetII header (including
      the Ethertype bitstring).

   o  Improved relationship between two paragraphs describing the
      increase of the Sequence Number in 802.11 header upon IP
      fragmentation.




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   o  Added brief clarification of "tracking".

   From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave-
   ipv6-over-80211ocb-01

   o  Introduced message exchange diagram illustrating differences
      between 802.11 and 802.11 in OCB mode.

   o  Introduced an appendix listing for information the set of 802.11
      messages that may be transmitted in OCB mode.

   o  Removed appendix sections "Privacy Requirements", "Aut=
hentication
      Requirements" and "Security Certificate Generation".

   o  Removed appendix section "Non IP Communications".

   o  Introductory phrase in the Security Considerations section.

   o  Improved the definition of "OCB".

   o  Introduced theoretical stacked layers about IPv6 and IEEE layers
      including EPD.

   o  Removed the appendix describing the details of prohibiting IPv6 on
      certain channels relevant to 802.11-OCB.

   o  Added a brief reference in the privacy text about a precise clause
      in IEEE 1609.3 and .4.

   o  Clarified the definition of a Road Side Unit.

   o  Removed the discussion about security of WSA (because is non-IP).

   o  Removed mentioning of the GeoNetworking discussion.

   o  Moved references to scientific articles to a separate 'overview'
      draft, and referred to it.


Appendix B.  Changes Needed on a =
software driver 802.11a to become a

             802.11-OCB driver

   The 802.11p amendment modifies both the 802.11 stack's physical and
   MAC layers but all the induced modifications can be quite easily
   obtained by modifying an existing 802.11a ad-hoc stack.

   Conditions for a 802.11a hardware to be 802.11-OCB compliant:





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   o  The chip must support the frequency bands on which the regulator
      recommends the use of ITS communications, for example using IEEE
      802.11-OCB layer, in France: 5875MHz to 5925MHz.

   o  The chip must support the half-rate mode (the internal clock
      should be able to be divided by two).

   o  The chip transmit spectrum mask must be compliant to the "Transm=
it
      spectrum mask" from the IEEE 802.11p amendment (but experimental
      environments tolerate otherwise).

   o  The chip should be able to transmit up to 44.8 dBm when used by
      the US government in the United States, and up to 33 dBm in
      Europe; other regional conditions apply.

   Changes needed on the network stack in OCB mode:

   o  Physical layer:

      *  The chip must use the Orthogonal Frequency Multiple Access
         (OFDM) encoding mode.

      *  The chip must be set in half-mode rate mode (the internal clock
         frequency is divided by two).

      *  The chip must use dedicated channels and should allow the use
         of higher emission powers.  This may require modifications to
         the regulatory domains rules, if used by the kernel to enforce
         local specific restrictions.  Such modifications must respect
         the location-specific laws.

      MAC layer:

      *  All management frames (beacons, join, leave, and others)
         emission and reception must be disabled except for frames of
         subtype Action and Timing Advertisement (defined below).

      *  No encryption key or method must be used.

      *  Packet emission and reception must be performed as in ad-hoc
         mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).

      *  The functions related to joining a BSS (Association Request/
         Response) and for authentication (Authentication Request/Reply,
         Challenge) are not called.

      *  The beacon interval is always set to 0 (zero).




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      *  Timing Advertisement frames, defined in the amendment, should
         be supported.  The upper layer should be able to trigger such
         frames emission and to retrieve information contained in
         received Timing Advertisements.


Appendix C.  Design Consideration=
s


   The networks defined by 802.11-OCB are in many ways similar to other
   networks of the 802.11 family.  In theory, the encapsulation of IPv6
   over 802.11-OCB could be very similar to the operation of IPv6 over
   other networks of the 802.11 family.  However, the high mobility,
   strong link asymetry and very short connection makes the 802.11-OCB
   link significantly different from other 802.11 networks.  Also, the
   automotive applications have specific requirements for reliability,
   security and privacy, which further add to the particularity of the
   802.11-OCB link.


C.1.  Vehicle ID


   Automotive networks require the unique representation of each of
   their node.  Accordingly, a vehicle must be identified by at least
   one unique identifier.  The current specification at ETSI and at IEEE
   1609 identifies a vehicle by its MAC address uniquely obtained from
   the 802.11-OCB NIC.

   A MAC address uniquely obtained from a IEEE 802.11-OCB NIC
   implicitely generates multiple vehicle IDs in case of multiple
   802.11-OCB NICs.  A mechanims to uniquely identify a vehicle
   irrespectively to the different NICs and/or technologies is required.


C.2.  Reliability Requireme=
nts


   The dynamically changing topology, short connectivity, mobile
   transmitter and receivers, different antenna heights, and many-to-
   many communication types, make IEEE 802.11-OCB links significantly
   different from other IEEE 802.11 links.  Any IPv6 mechanism operating
   on IEEE 802.11-OCB link MUST support strong link asymetry, spatio-
   temporal link quality, fast address resolution and transmission.

   IEEE 802.11-OCB strongly differs from other 802.11 systems to operate
   outside of the context of a Basic Service Set.  This means in
   practice that IEEE 802.11-OCB does not rely on a Base Station for all
   Basic Service Set management.  In particular, IEEE 802.11-OCB SHALL
   NOT use beacons.  Any IPv6 mechanism requiring L2 services from IEEE
   802.11 beacons MUST support an alternative service.






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   Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
   implement a mechanism for transmitter and receiver to converge to a
   common channel.

   Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST
   implement an distributed mechanism to authenticate transmitters and
   receivers without the support of a DHCP server.

   Time synchronization not being available, IPv6 over IEEE 802.11-OCB
   MUST implement a higher layer mechanism for time synchronization
   between transmitters and receivers without the support of a NTP
   server.

   The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB
   MUST disable management mechanisms requesting acknowledgements or
   replies.

   The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE
   802.11-OCB MUST implement fast IPv6 mobility management mechanisms.


C.3.  Multiple interfaces

   There are considerations for 2 or more IEEE 802.11-OCB interface
   cards per vehicle.  For each vehicle taking part in road traffic, one
   IEEE 802.11-OCB interface card could be fully allocated for Non IP
   safety-critical communication.  Any other IEEE 802.11-OCB may be used
   for other type of traffic.

   The mode of operation of these other wireless interfaces is not
   clearly defined yet.  One possibility is to consider each card as an
   independent network interface, with a specific MAC Address and a set
   of IPv6 addresses.  Another possibility is to consider the set of
   these wireless interfaces as a single network interface (not
   including the IEEE 802.11-OCB interface used by Non IP safety
   critical communications).  This will require specific logic to
   ensure, for example, that packets meant for a vehicle in front are
   actually sent by the radio in the front, or that multiple copies of
   the same packet received by multiple interfaces are treated as a
   single packet.  Treating each wireless interface as a separate
   network interface pushes such issues to the application layer.

   The privacy requirements of [] imply that if these multiple
   interfaces are represented by many network interface, a single
   renumbering event SHALL cause renumbering of all these interfaces.
   If one MAC changed and another stayed constant, external observers
   would be able to correlate old and new values, and the privacy
   benefits of randomization would be lost.




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   The privacy requirements of Non IP safety-critical communications
   imply that if a change of pseudonyme occurs, renumbering of all other
   interfaces SHALL also occur.


C.4.  MAC Address Generatio=
n


   When designing the IPv6 over 802.11-OCB address mapping, we will
   assume that the MAC Addresses will change during well defined
   "renumbering events".  The 48 bits randomized MAC addresses wi=
ll have
   the following characteristics:

   o  Bit "Local/Global" set to "locally admninistered"=
.

   o  Bit "Unicast/Multicast" set to "Unicast".

   o  46 remaining bits set to a random value, using a random number
      generator that meets the requirements of [RFC4086].

   The way to meet the randomization requirements is to retain 46 bits
   from the output of a strong hash function, such as SHA256, taking as
   input a 256 bit local secret, the "nominal" MAC Address of the
   interface, and a representation of the date and time of the
   renumbering event.


Appendix D.  IEEE 802.11 Messages=
 Transmitted in OCB mode


   For information, at the time of writing, this is the list of IEEE
   802.11 messages that may be transmitted in OCB mode, i.e. when
   dot11OCBActivated is true in a STA:

   o  The STA may send management frames of subtype Action and, if the
      STA maintains a TSF Timer, subtype Timing Advertisement;

   o  The STA may send control frames, except those of subtype PS-Poll,
      CF-End, and CF-End plus CFAck;

   o  The STA may send data frames of subtype Data, Null, QoS Data, and
      QoS Null.

Authors' Addresses







_______________________________________________

its mailing list

its@ietf.org

https://www.ietf.org/=
mailman/listinfo/its



















--_000_D5C97B5122C12Fsgundaveciscocom_--


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From: =?iso-8859-1?Q?Fran=E7ois_Simon?= 
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Mr. Gundaveli,

I provided some comments and responses in the text below your comments
identified by =93[Fygs] and =93bold=94.

If you have additional questions, please, let me know.

Sincerely,

Francois Simon

From: its [mailto:its-bounces@ietf.org] On Behalf Of Sri Gundavelli
(sgundave)
Sent: Sunday, August 27, 2017 11:01 PM
To: its@ietf.org
Subject: [ipwave] Review comments on
draft-ietf-ipwave-ipv6-over-80211ocb-04.txt


Attached is my review feedback.=20

In general there is lot of good information in the document. But, there =
are
also few areas where additional clarifications will greatly help.

1.) Its not clear, if the document makes any assumption on the operating
environment/communication profile. There is not much discussion on that
aspect; For example, Is it always a one-hop communication between RSU =
and
OBU where the 802.11-OCB link?  So, is the use of IPv6 only in that =
context
of 1-hop communication?=20

2.) There is also no discussion on how these links get formed in =
vehicular
environment and when they are attached/detached.=20

3.) How do nodes discover each other?  How does ND resolution work? Are
these messages received by a multiple RSU=92s, or a single RSU? Whats =
the
implication of that. Note that you don=92t have that issue in 802.11, =
given
the association to an access point, which in turn maps the links to a
VLAN/subnet.

4.) What happens as a vehicle moves between RSU=92s, how does it impact
address configuration?   Is DHCPv6 based address configuration relevant
here?


 Please see inline for additional comments.



------------------------------------------------------------------

=20
Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside

       =20
the Context of a Basic Service Set (IPv6-over-80211ocb)

             =20
draft-ietf-ipwave-ipv6-over-80211ocb-04.txt



[Sri] May be change to, =93..in mode .." =97> =93..operating in mode =
..=94  ?
[Fygs] Agreed


Abstract

   In order to transmit IPv6 packets on IEEE 802.11 networks run outside
   the context of a basic service set (OCB, earlier "802.11p") there is
   a need to define a few parameters such as the recommended Maximum
   Transmission Unit size, the header format preceding the IPv6 header,
   the Type value within it, and others.  This document describes these
   parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
   layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
   Ethernet layers - by using an Ethernet Adaptation Layer.

[Sri] Is it =93recommended MTU size", or "supported MTU size on the =
802.11 OCB
link? =20


   In addition, the document attempts to list what is different in
   802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
   layers, layers over which IPv6 protocols operates without issues.
   Most notably, the operation outside the context of a BSS (OCB) has
   impact on IPv6 handover behaviour and on IPv6 security.

[Sri] Minor comment. May be instead of using the =93layer=94 =
terminology, you
may want to present this as IPv6 support on "802.11 OCB" links.
[Fygs] 802.11 OCB provides data link and PHY services to IPv6
=20

   An example of an IPv6 packet captured while transmitted over an IEEE
   802.11 OCB link (802.11p) is given.

[Sri] Last paragraph can be ommitted in my view. That=92s too much of =
detail
for Abstract.
[Fygs] - Agree

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of https://tools.ietf.org/html/bcp78 and
https://tools.ietf.org/html/bcp79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute



Petrescu, et al.        Expires February 18, 2018               [Page 1]
________________________________________
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
2
Internet-Draft             IPv6-over-80211ocb                August 2017


   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 18, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to https://tools.ietf.org/html/bcp78 and the
IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
3
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
5
   3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    6
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
4.  Aspects introduced by the OCB mode to 802.11  . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
6
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.  Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
10
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.1.  Maximum Transmission Unit (MTU) . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
10
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.2.  Frame Format  . . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
11
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.2.1.  Ethernet Adaptation Layer . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
12
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.3.  Link-Local Addresses  . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
13
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.4.  Address Mapping . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
14
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.4.1.  Address Mapping -- Unicast  . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
14
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.4.2.  Address Mapping -- Multicast  . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
14
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.5.  Stateless Autoconfiguration . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
15
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.6.  Subnet Structure  . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
16
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
6.  Example IPv6 Packet captured over a IEEE 802.11-OCB link  . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
16
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
6.1.  Capture in Monitor Mode . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
17
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
6.2.  Capture in Normal Mode  . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
19
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
7.  Security Considerations . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
21
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
22
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
22
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
22



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________________________________________
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3
Internet-Draft             IPv6-over-80211ocb                August 2017


=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
11. References  . . . . . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
23
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
11.1.  Normative References . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
23
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
11.2.  Informative References . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
24
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-A.  ChangeLog  . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
26
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-B.  Changes Needed on a software driver 802.11a to
                become a                     802.11-OCB driver . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
28
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.  Design Considerations  . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
30
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.1.  Vehicle ID  . . . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
30
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.2.  Reliability Requirements  . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
30
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.3.  Multiple interfaces . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
31
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.4.  MAC Address Generation  . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
32
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-D.  IEEE 802.11 Messages Transmitted in OCB mode . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
32
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
32

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
1.  Introduction


   This document describes the transmission of IPv6 packets on IEEE Std
   802.11 OCB networks (earlier known as 802.11p). =20

[Sri] Please add a reference to the IEEE specification that defines the =
OCB
mode.=20
[Fygs] Since 2010 the OCB is defined in IEEE Std 802.11p, IEEE Std
802.11-2012, and IEEE 802.11-2016.


This involves the
   layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with
   an LLC layer).  Compared to running IPv6 over the Ethernet MAC layer,
   there is no modification required to the standards: IPv6 works fine
   directly over 802.11 OCB too (with an LLC layer).

   The term "802.11p" is an earlier definition.  As of year 2012, the
   behaviour of "802.11p" networks has been rolled in the document IEEE
   Std 802.11-2012.  In this document the term 802.11p disappears.
   Instead, each 802.11p feature is conditioned by a flag in the
   Management Information Base.  That flag is named "OCBActivated".
   Whenever OCBActivated is set to true the feature it relates to
   represents an earlier 802.11p feature.  For example, an 802.11
   STAtion operating outside the context of a basic service set has the
   OCBActivated flag set.  Such a station, when it has the flag set, it
   uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.

   In the following text we use the term "802.11p" to mean 802.11-2012
   OCB.

   The IPv6 network layer operates on 802.11 OCB in the same manner as
   it operates on 802.11 WiFi, with a few particular exceptions.  The
   IPv6 network layer operates on WiFi by involving an Ethernet
   Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers
   to Ethernet II headers.  The operation of IP on Ethernet is described
   in [https://tools.ietf.org/html/rfc1042] and
[https://tools.ietf.org/html/rfc2464].  The situation of IPv6 networking
layer
   on Ethernet Adaptation Layer is illustrated below:







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                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |                 IPv6                  |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |       Ethernet Adaptation Layer       |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi MAC           |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             802.11 WiFi PHY           |
                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   (in the above figure, a WiFi profile is represented; this is used
   also for OCB profile.)

   A more theoretical and detailed view of layer stacking, and
   interfaces between the IP layer and 802.11 OCB layers, is illustrated
   below.  The IP layer operates on top of the EtherType Protocol
   Discrimination (EPD); this Discrimination layer is described in IEEE
   Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP
   (Link Layer Control Service Accesss Point).


           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           |                 IPv6                  |
           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+
                       {   LLC_SAP  }                 802.11 OCB
           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+  Boundary
           |            EPD          |       |     |
           |                         | MLME  |     |
           +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   |
           |      MAC Sublayer       |       |     |  802.11 OCB
           |     and ch. coord.      |       | SME |  Services
           +-+-+-{   PHY_SAP  }+-+-+-+-+-+-+-|     |
           |                         | PLME  |     |
           |            PHY Layer    |   PLME_SAP  |
           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   In addition to the description of interface between IP and MAC using
   "Ethernet Adaptation Layer" and "Ethernet Protocol Discrimination
   (EPD)" it is worth mentioning that SNAP
[https://tools.ietf.org/html/rfc1042] is used to carry
   the IPv6 Ethertype.

   However, there may be some deployment considerations helping optimize
   the performances of running IPv6 over 802.11-OCB (e.g. in the case of
   handovers between 802.11 OCB-enabled access routers, or the
   consideration of using the IP security layer
[https://tools.ietf.org/html/rfc4301]).




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   There are currently no specifications for handover between OCB links
   since these are currently specified as LLC-1 links (i.e.
   connectionless).  Any handovers must be performed above the Data Link
   Layer.  Also, while there is no encryption applied below the network
   layer using 802.11p, 1609.2
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
iee
e1609.2] does provide security
   services for applications to use so that there can easily be data
   security over the air without invoking IPsec.

   We briefly introduce the vehicular communication scenarios where IEEE
   802.11-OCB links are used.=20

[Sri] I have not seen much discussion on the link / communication
assumptions.=20
[Fygs] Not sure of what is meant by assumptions in this context.


 This is followed by a description of
   differences in specification terms, between 802.11 OCB and
   802.11a/b/g/n (and the same differences expressed in terms of
   requirements to software implementation are listed in
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-B.)

   The document then concentrates on the parameters of layering IP over
   802.11 OCB as over Ethernet: value of MTU, the contents of Frame
   Format, the rules for forming Interface Identifiers, the mechanism
   for Address Mapping and for State-less Address Auto-configuration.
   These are precisely the same as IPv6 over Ethernet
[https://tools.ietf.org/html/rfc2464].

   As an example, these characteristics of layering IPv6 straight over
   LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet
   captured over a 802.11 OCB link; this is described in the section
=20
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
6.

   A couple of points can be considered as different, although they are
   not required in order to have a working implementation of IPv6-over-
   802.11-OCB.  These points are consequences of the OCB operation which
   is particular to 802.11 OCB (Outside the Context of a BSS).  First,
   the handovers between OCB links need specific behaviour for IP Router
   Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of
   higher layer messages such as the 'Basic Safety Message' (in the US)
   or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE
   Routing Advertisement'; second, the IP security mechanisms are
   necessary, since OCB means that 802.11 is stripped of all 802.11
   link-layer security; a small additional security aspect which is
   shared between 802.11 OCB and other 802.11 links is the privacy
   concerns related to the address formation mechanisms.

   In the published literature, many documents describe aspects related
   to running IPv6 over 802.11 OCB:
=20
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
I-D
.jeong-ipwave-vehicular-networking-survey].

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
2.  Terminology


   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in
https://tools.ietf.org/html/rfc2119 =
[https://tools.ietf.org/html/rfc2119].



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   RSU: Road Side Unit.  A computer equipped with at least one IEEE
   802.11 interface operated in OCB mode.  This definition applies to
   this document.  An RSU may be connected to the Internet, and may be
   equipped with additional wired or wireless network interfaces running
   IP.  An RSU MAY be an IP Router.


[Sri] RSU can be compared to an 802.11 access point; Or, WTP as defined =
in
CAPWAP specification, RFC5415.
[Fygs] While I am not familiar with =93WTP as defined in CAPWAP =
specification,
RFC5415=94, I know that an RSU has no commonality with an 802.11 AP.

Perhaps. rephrase as below?:

"RSU: Road Side Unit. Its a wireless termination point (WTP), as defined =
in
RFC5415 with one key difference, where the wireless physical and the mac
layer is MAC layers configured to operate in 802.11 OCB mode.  The RSU
communicates with the On board Unit (OBU) in the vehicle over 802.11
wireless link operating in OCB mode.=94=20
[Fygs]:  This seems reasonable and accurate.  This would be for V2I =
mode.


** Also, since you are defining the RSU term, should you also not define =
OBU
(On board Unit) in the vehicle which is the entity on the other end of =
the
link? =93RSU ----802.11-OCB=97=97OBU=94 ? May be introduce the OCB =
definition
separately, just as you did with RSU, and show the communication link as
802.11-OCB.
[Fygs] Here is a definition of OBU (FCC): =93An On-Board Unit is a DSRCS
transceiver that is normally mounted in or on a vehicle, or which in =
some
instances may be a portable unit. An OBU can be operational while a =
vehicle
or person is either mobile or stationary.=94


   OCB: outside the context of a basic service set (BSS): A mode of
   operation in which a STA is not a member of a BSS and does not
   utilize IEEE Std 802.11 authentication, association, or data
   confidentiality.

   802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is
   flagged by "dot11OCBActivated".  This means: IEEE 802.11e for quality
   of service; 802.11j-2004 for half-clocked operations; and (what was
   known earlier as) 802.11p for operation in the 5.9 GHz band and in
   mode OCB.


[Sri] The text starting with. =93This means=94 is not clear to me. Does =
it
802.11e is supported with 802.11OCB mode. Please clarify
[Fygs] QoS is required for 802.11 OCB.=20


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
3.  Communication Scenarios where IEEE 802.11 OCB Links are Used


   The IEEE 802.11 OCB Networks are used for vehicular communications,
   as 'Wireless Access in Vehicular Environments'.  The IP communication
   scenarios for these environments have been described in several
   documents, among which we refer the reader to one recently updated
=20
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
I-D
.petrescu-its-scenarios-reqs], about scenarios and requirements
   for IP in Intelligent Transportation Systems.


[Sri] You can do bit more justice to this section.=20
Explain the link model.  =93STA ----802.11-OCB=97=97STA=94. Then talk =
about the
applicability in Vehicular networks, with STA's as RSU and OCB.
You may also want to talk about, how links get formed/terminated; how =
nodes
peer/discover and how mobility works ..etc.  While 802.11-OCB is clearly
specified and the use of IPv6 over such link is also not radically new, =
but
the operating environment which is vehicular brings many new things. =
That
description is not present any where.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
4.  Aspects introduced by the OCB mode to 802.11


   In the IEEE 802.11 OCB mode, all nodes in the wireless range can
   directly communicate with each other without authentication/
   association procedures.  Briefly, the IEEE 802.11 OCB mode has the
   following properties:


[Sri] Can you add some text on how nodes (ST1 and STA2) discover each =
other
on such links supporting 802.11 OCB mode.
   o  The use by each node of a 'wildcard' BSSID (i.e., each bit of the
      BSSID is set to 1)

   o  No IEEE 802.11 Beacon frames transmitted

   o  No authentication required

   o  No association needed

o	No encryption provided

[Fygs] All the nodes in the communication range (OBU and RSU) receives =
all
the messages transmitted (OBU and RSU) within the communications range. =
The
conflicts are resolved by the MAC CDMA function. =20

[Sri] Can you clarify what you mean when you say =93No xxx required=94 / =
=93No xxx
needed=94  for the above capabilities.  What does =93needed=94 or =
=93required=94 mean?
Does it mean, =93Authentication", =93Association" and =93Encryption=94 =
is optional
on this link, or that its not supported on 802.11 OCB links.
[Fygs] The original text in IEEE 802.11p specifies:=20

=93Change the lettered list items (a) through (c) of 5.3.1 as follows:
a) Authentication (not used when dot11OCBEnabled is true)
b) Deauthentication (not used when dot11OCBEnabled is true)
c) Data confidentiality (not used when dot11OCBEnabled is true)=94 =20

   o  Flag dot11OCBActivated set to true

   The following message exchange diagram illustrates a comparison
   between traditional 802.11 and 802.11 in OCB mode.  The 'Data'



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   messages can be IP messages such as the messages used in Stateless or
   Stateful Address Auto-Configuration, or other IP messages. =20


[Sri] Lets separate the discussion on IP Address configuration using
SLAAC/DHCP on such links from the above description. The Data packets =
here
can be application packets such as HTTP or other packets. May be =
additional
discussion is needed on the IP address configuration on 802.11-OCB =
links.=20


Other
   802.11 management and control frames (non IP) may be transmitted, as
   specified in the 802.11 standard.  For information, the names of
   these messages as currently specified by the 802.11 standard are
   listed in
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-D.






     STA                    AP              STA1                   STA2
     |                      |               |                      |
     |<------ Beacon -------|               |<------ Data -------->|
     |                      |               |                      |
     |---- Probe Req. ----->|               |<------ Data -------->|
     |<--- Probe Res. ------|               |                      |
     |                      |               |<------ Data -------->|
     |---- Auth Req. ------>|               |                      |
     |<--- Auth Res. -------|               |<------ Data -------->|
     |                      |               |                      |
     |---- Asso Req. ------>|               |<------ Data -------->|
     |<--- Asso Res. -------|               |                      |
     |                      |               |<------ Data -------->|
     |<------ Data -------->|               |                      |
     |<------ Data -------->|               |<------ Data -------->|

    (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode


   The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010
=20
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
iee
e802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007,
   titled "Amendment 6: Wireless Access in Vehicular Environments".
   Since then, this amendment has been included in IEEE 802.11(TM)-2012
=20
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
iee
e802.11-2012], titled "IEEE Standard for Information technology--
   Telecommunications and information exchange between systems Local and
   metropolitan area networks--Specific requirements Part 11: Wireless
   LAN Medium Access Control (MAC) and Physical Layer (PHY)
   Specifications"; the modifications are diffused throughout various
   sections (e.g. the Time Advertisement message described in the
   earlier 802.11 (TM) p amendment is now described in section 'Frame
   formats', and the operation outside the context of a BSS described in
   section 'MLME').

   In document 802.11-2012, specifically anything referring
   "OCBActivated", or "outside the context of a basic service set" is
   actually referring to the 802.11p aspects introduced to 802.11.  Note
   that in earlier 802.11p documents the term "OCBEnabled" was used
   instead of te current "OCBActivated".





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   In order to delineate the aspects introduced by 802.11 OCB to 802.11,
   we refer to the earlier
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
iee
e802.11p-2010].  The amendment is
   concerned with vehicular communications, where the wireless link is
   similar to that of Wireless LAN (using a PHY layer specified by
   802.11a/b/g/n), but which needs to cope with the high mobility factor
   inherent in scenarios of communications between moving vehicles, and
   between vehicles and fixed infrastructure deployed along roads.
   While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is
   concerned more with MAC modifications, and a little with PHY
   modifications; the others are mainly about PHY modifications.  It is
   possible in practice to combine a 'p' MAC with an 'a' PHY by
   operating outside the context of a BSS with OFDM at 5.4GHz.

   The 802.11 OCB links are specified to be compatible as much as
   possible with the behaviour of 802.11a/b/g/n and future generation
   IEEE WLAN links.  From the IP perspective, an 802.11 OCB MAC layer
   offers practically the same interface to IP as the WiFi and Ethernet
   layers do (802.11a/b/g/n and 802.3).


[Sri] A packet sent from a vehicle=92s OBU is received by a single RSU, =
or
multiple RSU=92s? How does the link-layer resolution happen?
[Fygs] Assuming that:
a)	If there are single or multiple RSUs in the communication range and
it is a multicast message, the single RSU or RSUs in the comm. range =
will
receive it (eventually). There is no resolution at the link layer. The
RSU(s) will determine their =93interest=94 based on the content of the =
message
at the higher layers (application);
b)	If there are single or multiple RSUs in the communication rand and
it is unicast message, then the link-layer resolves by the destination =
MAC
address.
=09

   To support this similarity statement (IPv6 is layered on top of LLC
   on top of 802.11 OCB similarly as on top of LLC on top of
   802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to
   analyze the differences between 802.11 OCB and 802.11 specifications.
   Whereas the 802.11p amendment specifies relatively complex and
   numerous changes to the MAC layer (and very little to the PHY layer),
   we note there are only a few characteristics which may be important
   for an implementation transmitting IPv6 packets on 802.11 OCB links.

   In the list below, the only 802.11 OCB fundamental points which
   influence IPv6 are the OCB operation and the 12Mbit/s maximum which
   may be afforded by the IPv6 applications.


[Sri] I am really not sure how link throughput (12Mbps) relates to "IPv6
support on OCB links".=20
[Fygs] First of all there is guarantee of 12 Mbps throughput because of
collisions and other interferences, 12 Mbps data rate was probably =
intended.
The data rates for 20 MHz channel spacing are 6, 9, 12, 18, 24, 36, 48, =
and
54 Mb/s with mandatory support of 6, 12, and 24 Mbps;
Data rates for 10 MHz channel spacing are 3, 4.5, 6, 9, 12, 18, 24, and =
27
Mb/s. with mandatory support of  3, 6, and 12 Mb/s.=20


   o  Operation Outside the Context of a BSS (OCB): the (earlier
      802.11p) 802.11-OCB links are operated without a Basic Service Set
      (BSS).  This means that the frames IEEE 802.11 Beacon, Association
      Request/Response, Authentication Request/Response, and similar,
      are not used.  The used identifier of BSS (BSSID) has a
      hexadecimal value always 0xffffffffffff (48 '1' bits, represented
      as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'
      BSSID), as opposed to an arbitrary BSSID value set by
      administrator (e.g.  'My-Home-AccessPoint').  The OCB operation -
      namely the lack of beacon-based scanning and lack of
      authentication - has a potentially strong impact on the use of the
      Mobile IPv6 protocol [https://tools.ietf.org/html/rfc6275] and on =
the
protocols for IP layer
      security [https://tools.ietf.org/html/rfc4301].


[Sri] The document till now has been arguing heavily on how IPv6 =
operates so
naturally on these links and now I see discussion on =93Impact to a =
high-level
protocol such as MIPv6=94. You may want to fix the earlier text. In any =
case,
the absence of link-layer security practically impacts every =
application,
not just MIPv6.  Also, MIPv6 does not make any assumptions on the =
link-layer
security.  Also, the the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes the
messages readable by all other RSU=92s in proximity. I think the =
discussion on
the nature of the link, who all see=92s the messages.. how L2 addresses =
are
resolved is not explained clearly.=20



   o  Timing Advertisement: is a new message defined in 802.11-OCB,
      which does not exist in 802.11a/b/g/n.  This message is used by



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      stations to inform other stations about the value of time.  It is
      similar to the time as delivered by a GNSS system (Galileo, GPS,
      ...) or by a cellular system.  This message is optional for
      implementation.  At the date of writing, an experienced reviewer
      considers that currently no field testing has used this message.
      Another implementor considers this feature implemented in an
      initial manner.  In the future, it is speculated that this message
      may be useful for very simple devices which may not have their own
      hardware source of time (Galileo, GPS, cellular network), or by
      vehicular devices situated in areas not covered by such network
      (in tunnels, underground, outdoors but shaded by foliage or
      buildings, in remote areas, etc.)


[Sri] The first part explaining Timing Advertisement messages is great, =
but
the rest of the commentary is unnecessary and not needed. We don=92t =
speculate
the protocol adoption success in IETF specifications, or about the
experience level of the =93reviewer" :)
[Fygs]: Absolutely agree.


   o  Frequency range: this is a characteristic of the PHY layer, with
      almost no impact to the interface between MAC and IP.  However, it
      is worth considering that the frequency range is regulated by a
      regional authority (ARCEP, ETSI, FCC, etc.); as part of the
      regulation process, specific applications are associated with
      specific frequency ranges.  In the case of 802.11-OCB, the
      regulator associates a set of frequency ranges, or slots within a
      band, to the use of applications of vehicular communications, in a
      band known as "5.9GHz".  This band is "5.9GHz" which is different
      from the bands "2.4GHz" or "5GHz" used by Wireless LAN.  However,
      as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz"
      bands is exempt from owning a license in EU (in US the 5.9GHz is a
      licensed band of spectrum; for the the fixed infrastructure an
      explicit FCC autorization is required; for an onboard device a
      'licensed-by-rule' concept applies: rule certification conformity
      is required); however technical conditions are different than
      those of the bands "2.4GHz" or "5GHz".  On one hand, the allowed
      power levels, and implicitly the maximum allowed distance between
      vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20
      dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum
      distance of approximately 1km, compared to approximately 50m.  On
      the other hand, specific conditions related to congestion
      avoidance, jamming avoidance, and radar detection are imposed on
      the use of DSRC (in US) and on the use of frequencies for
      Intelligent Transportation Systems (in EU), compared to Wireless
      LAN (802.11a/b/g/n).

   o  Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB,
      as opposed to IPv6 not being prohibited on any channel on which
      802.11a/b/g/n runs:

      *  Some channels are reserved for safety communications; the IPv6
         packets should not be sent on these channels.





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      *  At the time of writing, the prohibition is explicit at higher
         layer protocols providing services to the application; these
         higher layer protocols are specified in IEEE 1609 documents.

      *  National or regional specifications and regulations specify the
         use of different channels; these regulations must be followed.

   o  'Half-rate' encoding: as the frequency range, this parameter is
      related to PHY, and thus has not much impact on the interface
      between the IP layer and the MAC layer.

   o  In vehicular communications using 802.11-OCB links, there are
      strong privacy requirements with respect to addressing.  While the
      802.11-OCB standard does not specify anything in particular with
      respect to MAC addresses, in these settings there exists a strong
      need for dynamic change of these addresses (as opposed to the non-
      vehicular settings - real wall protection - where fixed MAC
      addresses do not currently pose some privacy risks).  This is
      further described in section
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
7.  A relevant function is
      described in IEEE 1609.3-2016
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
iee
e1609.3], clause 5.5.1 and IEEE
      1609.4-2016
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
iee
e1609.4], clause 6.7.

   Other aspects particular to 802.11-OCB which are also particular to
   802.11 (e.g. the 'hidden node' operation) may have an influence on
   the use of transmission of IPv6 packets on 802.11-OCB networks.  The
   subnet structure which may be assumed in 802.11-OCB networks is
   strongly influenced by the mobility of vehicles.


[Sri] Per my earlier comment, the link model, addressing ..etc needs to =
be
explained in more detail. It is not clear what exactly the =93subnet
structure=94 that is assumed in 802.11-OCB.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.  Layering of IPv6 over 802.11-OCB as over Ethernet


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.1.  Maximum Transmission Unit (MTU)


   The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is
   the same value as IPv6 packets on Ethernet links, as specified in
   [https://tools.ietf.org/html/rfc2464].  This value of the MTU =
respects
the recommendation that
   every link in the Internet must have a minimum MTU of 1280 octets
   (stated in [https://tools.ietf.org/html/rfc2460], and the =
recommendations
therein, especially
   with respect to fragmentation).  If IPv6 packets of size larger than
   1500 bytes are sent on an 802.11-OCB interface card then the IP stack
   will fragment.  In case there are IP fragments, the field "Sequence
   number" of the 802.11 Data header containing the IP fragment field is
   increased.

   Non-IP packets such as WAVE Short Message Protocol (WSMP) can be
   delivered on 802.11-OCB links.  Specifications of these packets are
   out of scope of this document, and do not impose any limit on the MTU
   size, allowing an arbitrary number of 'containers'.  Non-IP packets
   such as ETSI 'geonet' packets have an MTU of 1492 bytes.



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   The Equivalent Transmit Time on Channel is a concept that may be used
   as an alternative to the MTU concept.  A rate of transmission may be
   specified as well.  The ETTC, rate and MTU may be in direct
   relationship.

[Sri] The last paragraph needs some additional context. Did 802.11-OCB
introduce ETTC concept?
[Fygs] NO ! =20



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.2.  Frame Format


   IP packets are transmitted over 802.11-OCB as standard Ethernet
   packets.  As with all 802.11 frames, an Ethernet adaptation layer is
   used with 802.11-OCB as well.  This Ethernet Adaptation Layer
   performing 802.11-to-Ethernet is described in
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.2.1.  The
   Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD,
   or otherwise #86DD).

   The Frame format for transmitting IPv6 on 802.11-OCB networks is the
   same as transmitting IPv6 on Ethernet networks, and is described in
   https://tools.ietf.org/html/rfc2464#section-3.  The frame format for
transmitting IPv6
   packets over Ethernet is illustrated below:


                    0                   1
                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |          Destination          |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |             Source            |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    |             IPv6              |
                    +-                             -+
                    |            header             |
                    +-                             -+
                    |             and               |
                    +-                             -+
                    /            payload ...        /
                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    (Each tic mark represents one bit.)





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   Ethernet II Fields:

   Destination Ethernet Address
      the MAC destination address.

   Source Ethernet Address
      the MAC source address.

   1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
      binary representation of the EtherType value 0x86DD.

   IPv6 header and payload
      the IPv6 packet containing IPv6 header and payload.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.2.1.  Ethernet Adaptation Layer


   In general, an 'adaptation' layer is inserted between a MAC layer and
   the Networking layer.  This is used to transform some parameters
   between their form expected by the IP stack and the form provided by
   the MAC layer.  For example, an 802.15.4 adaptation layer may perform
   fragmentation and reassembly operations on a MAC whose maximum Packet
   Data Unit size is smaller than the minimum MTU recognized by the IPv6
   Networking layer.  Other examples involve link-layer address
   transformation, packet header insertion/removal, and so on.

   An Ethernet Adaptation Layer makes an 802.11 MAC look to IP
   Networking layer as a more traditional Ethernet layer.  At reception,
   this layer takes as input the IEEE 802.11 Data Header and the
   Logical-Link Layer Control Header and produces an Ethernet II Header.
   At sending, the reverse operation is performed.


 +--------------------+------------+-------------+---------+-----------+
 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer|
 +--------------------+------------+-------------+---------+-----------+
  \                               /                         \         /
    -----------------------------                             --------
                   ^---------------------------------------------/
                   |
           802.11-to-Ethernet Adaptation Layer
                   |
                   v
 +---------------------+-------------+---------+
 | Ethernet II Header  | IPv6 Header | Payload |
 +---------------------+-------------+---------+






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   The Receiver and Transmitter Address fields in the 802.11 Data Header
   contain the same values as the Destination and the Source Address
   fields in the Ethernet II Header, respectively.  The value of the
   Type field in the LLC Header is the same as the value of the Type
   field in the Ethernet II Header.

   The ".11 Trailer" contains solely a 4-byte Frame Check Sequence.

   The Ethernet Adaptation Layer performs operations in relation to IP
   fragmentation and MTU.  One of these operations is briefly described
   in section
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.1.

   In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11
   Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in
   the following figure:


+--------------------+-------------+-------------+---------+-----------+
| 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------+-----------+

or

+--------------------+-------------+-------------+---------+-----------+
| 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|
+--------------------+-------------+-------------+---------+-----------+


   The distinction between the two formats is given by the value of the
   field "Type/Subtype".  The value of the field "Type/Subtype" in the
   802.11 Data header is 0x0020.  The value of the field "Type/Subtype"
   in the 802.11 QoS header is 0x0028.

   The mapping between qos-related fields in the IPv6 header (e.g.
   "Traffic Class", "Flow label") and fields in the "802.11 QoS Data
   Header" (e.g.  "QoS Control") are not specified in this document.
   Guidance for a potential mapping is provided in
=20
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
I-D
.ietf-tsvwg-ieee-802-11], although it is not specific to OCB
   mode.



[Sri] The applicability of the QoS mapping draft to 802.11-OCB needs =
further
investigation, IMO.
[Fygs] I am not familiar with QoS control of IPv6.  As for the OCB MAC =
QoS
it is somewhat involved.  It is based on transmission priority of MAC
frames.  A higher priority frame is intended to be transmitted ahead of
lower priority frames.  If a detail process is required, please, let me =
know
and I would provide the text.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.3.  Link-Local Addresses


   The link-local address of an 802.11-OCB interface is formed in the
   same manner as on an Ethernet interface.  This manner is described in
   https://tools.ietf.org/html/rfc2464#section-5.



[Sri] Does this go against the 8064 recommendation on Interface =
identifier
generation?
May be RFC7217 for interface identifier generation in conjunction with =
the
link-local address generation per RFC2464





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https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.4.  Address Mapping


   For unicast as for multicast, there is no change from the unicast and
   multicast address mapping format of Ethernet interfaces, as defined
   by sections
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
6 and
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
7 of [https://tools.ietf.org/html/rfc2464].



[Sri] RFC6085 specified mapping is also relevant; If the communication =
peers
are aware that there is only one peer, it should apply 6085 specified
mapping. That mode is relevant for 802.11-OCB types links as well.


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.4.1.  Address Mapping -- Unicast


   The procedure for mapping IPv6 unicast addresses into Ethernet link-
   layer addresses is described in =
[https://tools.ietf.org/html/rfc4861].
The Source/Target Link-
   layer Address option has the following form when the link-layer is
   Ethernet.

[Sri] I thought, mapping of IPv6 unicast addresses to Ethernet =
link-layer
addresses is specified in section 6, of RFC2464 and not in RFC4861.



                      0                   1
                      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |     Type      |    Length     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |                               |
                     +-          Ethernet           -+
                     |                               |
                     +-           Address           -+
                     |                               |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Option fields:

   Type
      1 for Source Link-layer address.
      2 for Target Link-layer address.

   Length
      1 (in units of 8 octets).

   Ethernet Address
      The 48 bit Ethernet IEEE 802 address, in canonical bit order.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.4.2.  Address Mapping -- Multicast


   IPv6 protocols often make use of IPv6 multicast addresses in the
   destination field of IPv6 headers.  For example, an ICMPv6 link-
   scoped Neighbor Advertisement is sent to the IPv6 address ff02::1
   denoted "all-nodes" address.  When transmitting these packets on
   802.11-OCB links it is necessary to map the IPv6 address to a MAC
   address.




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   The same mapping requirement applies to the link-scoped multicast
   addresses of other IPv6 protocols as well.  In DHCPv6, the
   "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF the
   "All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped
   on a multicast MAC address.

   An IPv6 packet with a multicast destination address DST, consisting
   of the sixteen octets DST[1] through DST[16], is transmitted to the
   IEEE 802.11-OCB MAC multicast address whose first two octets are the
   value 0x3333 and whose last four octets are the last four octets of
   DST.

[Sri] Please add a reference to Section 7, RFC4861 and also RFC6085. In
general, for both unicast and multicast, you may want to clearly say =
that
this is per the existing specs and duplicated here for convenience.=20

                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |   DST[13]     |   DST[14]     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     |   DST[15]     |   DST[16]     |
                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   A Group ID TBD of length 112bits may be requested from IANA; this
   Group ID signifies "All 80211OCB Interfaces Address".  Only the least
   32 significant bits of this "All 80211OCB Interfaces Address" will be
   mapped to and from a MAC multicast address.

   Transmitting IPv6 packets to multicast destinations over 802.11 links
   proved to have some performance issues
=20
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
I-D
.perkins-intarea-multicast-ieee802].  These issues may be
   exacerbated in OCB mode.  Solutions for these problems should
   consider the OCB mode of operation.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.5.  Stateless Autoconfiguration


   The Interface Identifier for an 802.11-OCB interface is formed using
   the same rules as the Interface Identifier for an Ethernet interface;
   this is described in https://tools.ietf.org/html/rfc2464#section-4.  =
No
changes are needed,
   but some care must be taken when considering the use of the SLAAC
   procedure.


[Sri] Per my earlier comment, please refer to the current recommendation =
on
interface-identifier generation and its use in link-local, global or =
other
addresses.


   The bits in the the interface identifier have no generic meaning and
   the identifier should be treated as an opaque value.  The bits
   'Universal' and 'Group' in the identifier of an 802.11-OCB interface
   are significant, as this is an IEEE link-layer address.  The details
   of this significance are described in
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
I-D
.ietf-6man-ug].





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   As with all Ethernet and 802.11 interface identifiers
([https://tools.ietf.org/html/rfc7721]),
   the identifier of an 802.11-OCB interface may involve privacy risks.
   A vehicle embarking an On-Board Unit whose egress interface is
   802.11-OCB may expose itself to eavesdropping and subsequent
   correlation of data; this may reveal data considered private by the
   vehicle owner; there is a risk of being tracked; see the privacy
   considerations described in
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.


[Sri] I think there are other security issues here; the absence of
link-layer security opens up Mac-spoofing and IP address hijacking.  =
That
should be mentioned.


   If stable Interface Identifiers are needed in order to form IPv6
   addresses on 802.11-OCB links, it is recommended to follow the
   recommendation in
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-=
I-D
.ietf-6man-default-iids].

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
5.6.  Subnet Structure


   The 802.11 networks in OCB mode may be considered as 'ad-hoc'
   networks.  The addressing model for such networks is described in
   [https://tools.ietf.org/html/rfc5889].


[Sri] Per my earlier comment, there is no system level view of the =
network
where 802.11-OCB links are used. So, in the absence of such discussion =
So, I
am not sure what part of RFC5889 is applicable here. For example, =
link-local
addresses may just work fine.=20


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
6.  Example IPv6 Packet captured over a IEEE 802.11-OCB link


   We remind that a main goal of this document is to make the case that
   IPv6 works fine over 802.11-OCB networks.  Consequently, this section
   is an illustration of this concept and thus can help the implementer
   when it comes to running IPv6 over IEEE 802.11-OCB.  By way of
   example we show that there is no modification in the headers when
   transmitted over 802.11-OCB networks - they are transmitted like any
   other 802.11 and Ethernet packets.

   We describe an experiment of capturing an IPv6 packet on an
   802.11-OCB link.  In this experiment, the packet is an IPv6 Router
   Advertisement.  This packet is emitted by a Router on its 802.11-OCB
   interface.  The packet is captured on the Host, using a network
   protocol analyzer (e.g.  Wireshark); the capture is performed in two
   different modes: direct mode and 'monitor' mode.  The topology used
   during the capture is depicted below.


              +--------+                                +-------+
              |        |        802.11-OCB Link         |       |
           ---| Router |--------------------------------| Host  |
              |        |                                |       |
              +--------+                                +-------+


   During several capture operations running from a few moments to
   several hours, no message relevant to the BSSID contexts were
   captured (no Association Request/Response, Authentication Req/Resp,




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   Beacon).  This shows that the operation of 802.11-OCB is outside the
   context of a BSSID.

   Overall, the captured message is identical with a capture of an IPv6
   packet emitted on a 802.11b interface.  The contents are precisely
   similar.


[Sri] I suggest moving this discussion under the section =
=93Implementation
Status=94, which will eventually be removed from the RFC. There is =
nothing new
here. This are details on experimentation. But, if you think there is =
some
useful information  such as discussion on Capture mode ..etc, you may =
want
to move this entire section to Appendix. Implementors may use these =
tools
for verification.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
6.1.  Capture in Monitor Mode


   The IPv6 RA packet captured in monitor mode is illustrated below.
   The radio tap header provides more flexibility for reporting the
   characteristics of frames.  The Radiotap Header is prepended by this
   particular stack and operating system on the Host machine to the RA
   packet received from the network (the Radiotap Header is not present
   on the air).  The implementation-dependent Radiotap Header is useful
   for piggybacking PHY information from the chip's registers as data in
   a packet understandable by userland applications using Socket
   interfaces (the PHY interface can be, for example: power levels, data
   rate, ratio of signal to noise).

   The packet present on the air is formed by IEEE 802.11 Data Header,
   Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.



     Radiotap Header v0
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Header Revision|  Header Pad   |    Header length              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Present flags                         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Data Rate     |             Pad                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IEEE 802.11 Data Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Type/Subtype and Frame Ctrl  |          Duration             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Receiver Address...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Receiver Address           |      Transmitter Address...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Transmitter Address                                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                            BSS Id...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... BSS Id                     |  Frag Number and Seq Number   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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     Logical-Link Control Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |      DSAP   |I|     SSAP    |C| Control field | Org. code...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ... Organizational Code        |             Type              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                         Source Address                        +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                      Destination Address                      +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+-


   The value of the Data Rate field in the Radiotap header is set to 6
   Mb/s.  This indicates the rate at which this RA was received.





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   The value of the Transmitter address in the IEEE 802.11 Data Header
   is set to a 48bit value.  The value of the destination address is
   33:33:00:00:00:1 (all-nodes multicast address).  The value of the BSS
   Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network
   protocol analyzer as being "broadcast".  The Fragment number and
   sequence number fields are together set to 0x90C6.

   The value of the Organization Code field in the Logical-Link Control
   Header is set to 0x0, recognized as "Encapsulated Ethernet".  The
   value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise
   #86DD), recognized as "IPv6".

   A Router Advertisement is periodically sent by the router to
   multicast group address ff02::1.  It is an icmp packet type 134.  The
   IPv6 Neighbor Discovery's Router Advertisement message contains an
   8-bit field reserved for single-bit flags, as described in
[https://tools.ietf.org/html/rfc4861].

   The IPv6 header contains the link local address of the router
   (source) configured via EUI-64 algorithm, and destination address set
   to ff02::1.  Recent versions of network protocol analyzers (e.g.
   Wireshark) provide additional informations for an IP address, if a
   geolocalization database is present.  In this example, the
   geolocalization database is absent, and the "GeoIP" information is
   set to unknown for both source and destination addresses (although
   the IPv6 source and destination addresses are set to useful values).
   This "GeoIP" can be a useful information to look up the city,
   country, AS number, and other information for an IP address.

[Sri] Not sure, why all of this text should be in the specification.=20

   The Ethernet Type field in the logical-link control header is set to
   0x86dd which indicates that the frame transports an IPv6 packet.  In
   the IEEE 802.11 data, the destination address is 33:33:00:00:00:01
   which is he corresponding multicast MAC address.  The BSS id is a
   broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link
   duration between vehicles and the roadside infrastructure, there is
   no need in IEEE 802.11-OCB to wait for the completion of association
   and authentication procedures before exchanging data.  IEEE
   802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)
   and may start communicating as soon as they arrive on the
   communication channel.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
6.2.  Capture in Normal Mode


   The same IPv6 Router Advertisement packet described above (monitor
   mode) is captured on the Host, in the Normal mode, and depicted
   below.






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     Ethernet II Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Destination...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ...Destination                 |           Source...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ...Source                                                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |          Type                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Version| Traffic Class |           Flow Label                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Payload Length        |  Next Header  |   Hop Limit   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                         Source Address                        +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                      Destination Address                      +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |     Code      |          Checksum             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reachable Time                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Retrans Timer                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Options ...
     +-+-+-+-+-+-+-+-+-+-+-+-





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   One notices that the Radiotap Header is not prepended, and that the
   IEEE 802.11 Data Header and the Logical-Link Control Headers are not
   present.  On another hand, a new header named Ethernet II Header is
   present.

   The Destination and Source addresses in the Ethernet II header
   contain the same values as the fields Receiver Address and
   Transmitter Address present in the IEEE 802.11 Data Header in the
   "monitor" mode capture.

   The value of the Type field in the Ethernet II header is 0x86DD
   (recognized as "IPv6"); this value is the same value as the value of
   the field Type in the Logical-Link Control Header in the "monitor"
   mode capture.

   The knowledgeable experimenter will no doubt notice the similarity of
   this Ethernet II Header with a capture in normal mode on a pure
   Ethernet cable interface.

   It may be interpreted that an Adaptation layer is inserted in a pure
   IEEE 802.11 MAC packets in the air, before delivering to the
   applications.  In detail, this adaptation layer may consist in
   elimination of the Radiotap, 802.11 and LLC headers and insertion of
   the Ethernet II header.  In this way, it can be stated that IPv6 runs
   naturally straight over LLC over the 802.11-OCB MAC layer, as shown
   by the use of the Type 0x86DD, and assuming an adaptation layer
   (adapting 802.11 LLC/MAC to Ethernet II header).

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
7.  Security Considerations


   Any security mechanism at the IP layer or above that may be carried
   out for the general case of IPv6 may also be carried out for IPv6
   operating over 802.11-OCB.

   802.11-OCB does not provide any cryptographic protection, because it
   operates outside the context of a BSS (no Association Request/
   Response, no Challenge messages).  Any attacker can therefore just
   sit in the near range of vehicles, sniff the network (just set the
   interface card's frequency to the proper range) and perform attacks
   without needing to physically break any wall.  Such a link is way
   less protected than commonly used links (wired link or protected
   802.11).

[Sri] Per my earlier comment, there is more than one attack vector =
possible
1.) Absence of link-layer security and the potential for mac address
spoofing=20
2.) IP address / Session hijacking=20
3.) Data privacy per your text


   At the IP layer, IPsec can be used to protect unicast communications,
   and SeND can be used for multicast communications.=20

[Sri] IPSec can be used for protecting both multicast or unicast
communication; RFC-5374 with GDOI.



 If no protection
   is used by the IP layer, upper layers should be protected.
   Otherwise, the end-user or system should be warned about the risks
   they run.



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   As with all Ethernet and 802.11 interface identifiers, there may
   exist privacy risks in the use of 802.11-OCB interface identifiers.
   Moreover, in outdoors vehicular settings, the privacy risks are more
   important than in indoors settings.  New risks are induced by the
   possibility of attacker sniffers deployed along routes which listen
   for IP packets of vehicles passing by.  For this reason, in the
   802.11-OCB deployments, there is a strong necessity to use protection
   tools such as dynamically changing MAC addresses.  This may help
   mitigate privacy risks to a certain level.  On another hand, it may
   have an impact in the way typical IPv6 address auto-configuration is
   performed for vehicles (SLAAC would rely on MAC addresses amd would
   hence dynamically change the affected IP address), in the way the
   IPv6 Privacy addresses were used, and other effects.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
8.  IANA Considerations


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
9.  Contributors


   Romain Kuntz contributed extensively about IPv6 handovers between
   links running outside the context of a BSS (802.11-OCB links).

   Tim Leinmueller contributed the idea of the use of IPv6 over
   802.11-OCB for distribution of certificates.

   Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey
   Voronov provided significant feedback on the experience of using IP
   messages over 802.11-OCB in initial trials.

   Michelle Wetterwald contributed extensively the MTU discussion,
   offered the ETSI ITS perspective, and reviewed other parts of the
   document.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
10.  Acknowledgements


   The authors would like to thank Witold Klaudel, Ryuji Wakikawa,
   Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan
   Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray
   Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,
   Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,
   Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,
   Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and
   William Whyte.  Their valuable comments clarified certain issues and
   generally helped to improve the document.

   Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB
   drivers for linux and described how.





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   For the multicast discussion, the authors would like to thank Owen
   DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and
   participants to discussions in network working groups.

   The authours would like to thank participants to the Birds-of-
   a-Feather "Intelligent Transportation Systems" meetings held at IETF
   in 2016.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
11.  References


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
11.1.  Normative References


   [I-D.ietf-6man-default-iids]
              Gont, F., Cooper, A., Thaler, D., and S. LIU,
              "Recommendation on Stable IPv6 Interface Identifiers",
              =
https://tools.ietf.org/html/draft-ietf-6man-default-iids-16
(work in progress),
              September 2016.

   [I-D.ietf-6man-ug]
              Carpenter, B. and S. Jiang, "Significance of IPv6
              Interface Identifiers",
https://tools.ietf.org/html/draft-ietf-6man-ug-06 (work in
              progress), December 2013.

   [I-D.ietf-tsvwg-ieee-802-11]
              Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE
              802.11 Mapping",
https://tools.ietf.org/html/draft-ietf-tsvwg-ieee-802-11-06 (work in
              progress), August 2017.

   [RFC1042]  Postel, J. and J. Reynolds, "Standard for the transmission
              of IP datagrams over IEEE 802 networks", STD 43,
https://tools.ietf.org/html/rfc1042,
              DOI 10.17487/RFC1042, February 1988,
.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", https://tools.ietf.org/html/bcp14,
https://tools.ietf.org/html/rfc2119,
              DOI 10.17487/RFC2119, March 1997,
.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", =
https://tools.ietf.org/html/rfc2460,
DOI 10.17487/RFC2460,
              December 1998, .

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", https://tools.ietf.org/html/rfc2464, DOI
10.17487/RFC2464, December 1998,
              .






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   [RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol",
              https://tools.ietf.org/html/rfc3963, DOI 10.17487/RFC3963,
January 2005,
              .

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security",
https://tools.ietf.org/html/bcp106, https://tools.ietf.org/html/rfc4086,
              DOI 10.17487/RFC4086, June 2005,
.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", https://tools.ietf.org/html/rfc4301, =
DOI
10.17487/RFC4301,
              December 2005, .

   [RFC4429]  Moore, N., "Optimistic Duplicate Address Detection (DAD)
              for IPv6", https://tools.ietf.org/html/rfc4429, DOI
10.17487/RFC4429, April 2006,
              .

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)",
https://tools.ietf.org/html/rfc4861,
              DOI 10.17487/RFC4861, September 2007,
.

   [RFC5889]  Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing
              Model in Ad Hoc Networks",
https://tools.ietf.org/html/rfc5889, DOI 10.17487/RFC5889,
              September 2010, .

   [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", https://tools.ietf.org/html/rfc6275, DOI
10.17487/RFC6275, July
              2011, .

   [RFC6775]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
              Bormann, "Neighbor Discovery Optimization for IPv6 over
              Low-Power Wireless Personal Area Networks (6LoWPANs)",
              https://tools.ietf.org/html/rfc6775, DOI 10.17487/RFC6775,
November 2012,
              .

   [RFC7721]  Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
              Considerations for IPv6 Address Generation Mechanisms",
              https://tools.ietf.org/html/rfc7721, DOI 10.17487/RFC7721,
March 2016,
              .

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#secti=
on-
11.2.  Informative References









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   [fcc-cc]   "'Report and Order, Before the Federal Communications
              Commission Washington, D.C. 20554', FCC 03-324, Released
              on February 10, 2004, document FCC-03-324A1.pdf, document
              freely available at URL
              http://www.its.dot.gov/exit/fcc_edocs.htm downloaded on
              October 17th, 2013.".

   [fcc-cc-172-184]
              "'Memorandum Opinion and Order, Before the Federal
              Communications Commission Washington, D.C. 20554', FCC
              06-10, Released on July 26, 2006, document FCC-
              06-110A1.pdf, document freely available at URL
=20
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A1.pdf
=20
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A1.pdf
downloaded on June 5th, 2014.".

   [I-D.jeong-ipwave-vehicular-networking-survey]
              Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M.
              Wetterwald, "Survey on IP-based Vehicular Networking for
              Intelligent Transportation Systems",
https://tools.ietf.org/html/draft-jeong-ipwave-vehicular-networking-surve=
y-0
3
=20
https://tools.ietf.org/html/draft-jeong-ipwave-vehicular-networking-surve=
y-0
3 (work in progress), June
              2017.

   [I-D.perkins-intarea-multicast-ieee802]
              Perkins, C., Stanley, D., Kumari, W., and J. Zuniga,
              "Multicast Considerations over IEEE 802 Wireless Media",
=20
https://tools.ietf.org/html/draft-perkins-intarea-multicast-ieee802-03 =
(work
in
              progress), July 2017.

   [I-D.petrescu-its-scenarios-reqs]
              Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel,
              "Scenarios and Requirements for IP in Intelligent
              Transportation Systems",
https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs-03
=20
https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs-03 (work =
in
progress), October 2013.

   [ieee1609.2]
              "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Security Services for
              Applications and Management Messages.  Example URL
              http://ieeexplore.ieee.org/document/7426684/ accessed on
              August 17th, 2017.".

   [ieee1609.3]
              "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Networking Services.
              Example URL
http://ieeexplore.ieee.org/document/7458115/accessed
              http://ieeexplore.ieee.org/document/7458115/accessed on =
August
17th, 2017.".





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   [ieee1609.4]
              "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access
              in Vehicular Environments (WAVE) -- Multi-Channel
              Operation.  Example URL
              http://ieeexplore.ieee.org/document/7435228/ accessed on
              August 17th, 2017.".

   [ieee802.11-2012]
              "802.11-2012 - IEEE Standard for Information technology--
              Telecommunications and information exchange between
              systems Local and metropolitan area networks--Specific
              requirements Part 11: Wireless LAN Medium Access Control
              (MAC) and Physical Layer (PHY) Specifications.  Downloaded
              on October 17th, 2013, from IEEE Standards, document
              freely available at URL
              =
http://standards.ieee.org/findstds/standard/802.11-2012.html
              =
http://standards.ieee.org/findstds/standard/802.11-2012.html
retrieved on October 17th,
              2013.".

   [ieee802.11p-2010]
              "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information
              Technology - Telecommunications and information exchange
              between systems - Local and metropolitan area networks -
              Specific requirements, Part 11: Wireless LAN Medium Access
              Control (MAC) and Physical Layer (PHY) Specifications,
              Amendment 6: Wireless Access in Vehicular Environments;
              document freely available at URL
              =
http://standards.ieee.org/getieee802/download/802.11p-2010.pdf
              =
http://standards.ieee.org/getieee802/download/802.11p-2010.pdf
retrieved on September 20th,
              2013.".

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-A.  ChangeLog


   The changes are listed in reverse chronological order, most recent
   changes appearing at the top of the list.

   From =
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03
to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04
   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04

   o  Removed a few informative references pointing to Dx draft IEEE
      1609 documents.

   o  Removed outdated informative references to ETSI documents.

   o  Added citations to IEEE 1609.2, .3 and .4-2016.

   o  Minor textual issues.




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   From =
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02
to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03
   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03

   o  Keep the previous text on multiple addresses, so remove talk about
      MIP6, NEMOv6 and MCoA.

   o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.

   o  Clarified the figure showing Infrastructure mode and OCB mode side
      by side.

   o  Added a reference to the IP Security Architecture RFC.

   o  Detailed the IPv6-per-channel prohibition paragraph which reflects
      the discussion at the last IETF IPWAVE WG meeting.

   o  Added section "Address Mapping -- Unicast".

   o  Added the ".11 Trailer" to pictures of 802.11 frames.

   o  Added text about SNAP carrying the Ethertype.

   o  New RSU definition allowing for it be both a Router and not
      necessarily a Router some times.

   o  Minor textual issues.

   From =
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01
to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02
   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02

   o  Replaced almost all occurences of 802.11p with 802.11-OCB, leaving
      only when explanation of evolution was necessary.

   o  Shortened by removing parameter details from a paragraph in the
      Introduction.

   o  Moved a reference from Normative to Informative.

   o  Added text in intro clarifying there is no handover spec at IEEE,
      and that 1609.2 does provide security services.

   o  Named the contents the fields of the EthernetII header (including
      the Ethertype bitstring).

   o  Improved relationship between two paragraphs describing the
      increase of the Sequence Number in 802.11 header upon IP
      fragmentation.




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   o  Added brief clarification of "tracking".

   From =
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-00
to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01
   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01

   o  Introduced message exchange diagram illustrating differences
      between 802.11 and 802.11 in OCB mode.

   o  Introduced an appendix listing for information the set of 802.11
      messages that may be transmitted in OCB mode.

   o  Removed appendix sections "Privacy Requirements", "Authentication
      Requirements" and "Security Certificate Generation".

   o  Removed appendix section "Non IP Communications".

   o  Introductory phrase in the Security Considerations section.

   o  Improved the definition of "OCB".

   o  Introduced theoretical stacked layers about IPv6 and IEEE layers
      including EPD.

   o  Removed the appendix describing the details of prohibiting IPv6 on
      certain channels relevant to 802.11-OCB.

   o  Added a brief reference in the privacy text about a precise clause
      in IEEE 1609.3 and .4.

   o  Clarified the definition of a Road Side Unit.

   o  Removed the discussion about security of WSA (because is non-IP).

   o  Removed mentioning of the GeoNetworking discussion.

   o  Moved references to scientific articles to a separate 'overview'
      draft, and referred to it.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-B.  Changes Needed on a software driver 802.11a to become a

             802.11-OCB driver

   The 802.11p amendment modifies both the 802.11 stack's physical and
   MAC layers but all the induced modifications can be quite easily
   obtained by modifying an existing 802.11a ad-hoc stack.

   Conditions for a 802.11a hardware to be 802.11-OCB compliant:





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   o  The chip must support the frequency bands on which the regulator
      recommends the use of ITS communications, for example using IEEE
      802.11-OCB layer, in France: 5875MHz to 5925MHz.

   o  The chip must support the half-rate mode (the internal clock
      should be able to be divided by two).

   o  The chip transmit spectrum mask must be compliant to the "Transmit
      spectrum mask" from the IEEE 802.11p amendment (but experimental
      environments tolerate otherwise).

   o  The chip should be able to transmit up to 44.8 dBm when used by
      the US government in the United States, and up to 33 dBm in
      Europe; other regional conditions apply.

   Changes needed on the network stack in OCB mode:

   o  Physical layer:

      *  The chip must use the Orthogonal Frequency Multiple Access
         (OFDM) encoding mode.

      *  The chip must be set in half-mode rate mode (the internal clock
         frequency is divided by two).

      *  The chip must use dedicated channels and should allow the use
         of higher emission powers.  This may require modifications to
         the regulatory domains rules, if used by the kernel to enforce
         local specific restrictions.  Such modifications must respect
         the location-specific laws.

      MAC layer:

      *  All management frames (beacons, join, leave, and others)
         emission and reception must be disabled except for frames of
         subtype Action and Timing Advertisement (defined below).

      *  No encryption key or method must be used.

      *  Packet emission and reception must be performed as in ad-hoc
         mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).

      *  The functions related to joining a BSS (Association Request/
         Response) and for authentication (Authentication Request/Reply,
         Challenge) are not called.

      *  The beacon interval is always set to 0 (zero).




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      *  Timing Advertisement frames, defined in the amendment, should
         be supported.  The upper layer should be able to trigger such
         frames emission and to retrieve information contained in
         received Timing Advertisements.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.  Design Considerations


   The networks defined by 802.11-OCB are in many ways similar to other
   networks of the 802.11 family.  In theory, the encapsulation of IPv6
   over 802.11-OCB could be very similar to the operation of IPv6 over
   other networks of the 802.11 family.  However, the high mobility,
   strong link asymetry and very short connection makes the 802.11-OCB
   link significantly different from other 802.11 networks.  Also, the
   automotive applications have specific requirements for reliability,
   security and privacy, which further add to the particularity of the
   802.11-OCB link.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.1.  Vehicle ID


   Automotive networks require the unique representation of each of
   their node.  Accordingly, a vehicle must be identified by at least
   one unique identifier.  The current specification at ETSI and at IEEE
   1609 identifies a vehicle by its MAC address uniquely obtained from
   the 802.11-OCB NIC.

   A MAC address uniquely obtained from a IEEE 802.11-OCB NIC
   implicitely generates multiple vehicle IDs in case of multiple
   802.11-OCB NICs.  A mechanims to uniquely identify a vehicle
   irrespectively to the different NICs and/or technologies is required.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.2.  Reliability Requirements


   The dynamically changing topology, short connectivity, mobile
   transmitter and receivers, different antenna heights, and many-to-
   many communication types, make IEEE 802.11-OCB links significantly
   different from other IEEE 802.11 links.  Any IPv6 mechanism operating
   on IEEE 802.11-OCB link MUST support strong link asymetry, spatio-
   temporal link quality, fast address resolution and transmission.

   IEEE 802.11-OCB strongly differs from other 802.11 systems to operate
   outside of the context of a Basic Service Set.  This means in
   practice that IEEE 802.11-OCB does not rely on a Base Station for all
   Basic Service Set management.  In particular, IEEE 802.11-OCB SHALL
   NOT use beacons.  Any IPv6 mechanism requiring L2 services from IEEE
   802.11 beacons MUST support an alternative service.






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   Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
   implement a mechanism for transmitter and receiver to converge to a
   common channel.

   Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST
   implement an distributed mechanism to authenticate transmitters and
   receivers without the support of a DHCP server.

   Time synchronization not being available, IPv6 over IEEE 802.11-OCB
   MUST implement a higher layer mechanism for time synchronization
   between transmitters and receivers without the support of a NTP
   server.

   The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB
   MUST disable management mechanisms requesting acknowledgements or
   replies.

   The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE
   802.11-OCB MUST implement fast IPv6 mobility management mechanisms.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.3.  Multiple interfaces


   There are considerations for 2 or more IEEE 802.11-OCB interface
   cards per vehicle.  For each vehicle taking part in road traffic, one
   IEEE 802.11-OCB interface card could be fully allocated for Non IP
   safety-critical communication.  Any other IEEE 802.11-OCB may be used
   for other type of traffic.

   The mode of operation of these other wireless interfaces is not
   clearly defined yet.  One possibility is to consider each card as an
   independent network interface, with a specific MAC Address and a set
   of IPv6 addresses.  Another possibility is to consider the set of
   these wireless interfaces as a single network interface (not
   including the IEEE 802.11-OCB interface used by Non IP safety
   critical communications).  This will require specific logic to
   ensure, for example, that packets meant for a vehicle in front are
   actually sent by the radio in the front, or that multiple copies of
   the same packet received by multiple interfaces are treated as a
   single packet.  Treating each wireless interface as a separate
   network interface pushes such issues to the application layer.

   The privacy requirements of [] imply that if these multiple
   interfaces are represented by many network interface, a single
   renumbering event SHALL cause renumbering of all these interfaces.
   If one MAC changed and another stayed constant, external observers
   would be able to correlate old and new values, and the privacy
   benefits of randomization would be lost.




Petrescu, et al.        Expires February 18, 2018              [Page 31]
________________________________________
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-=
32
Internet-Draft             IPv6-over-80211ocb                August 2017


   The privacy requirements of Non IP safety-critical communications
   imply that if a change of pseudonyme occurs, renumbering of all other
   interfaces SHALL also occur.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-C.4.  MAC Address Generation


   When designing the IPv6 over 802.11-OCB address mapping, we will
   assume that the MAC Addresses will change during well defined
   "renumbering events".  The 48 bits randomized MAC addresses will have
   the following characteristics:

   o  Bit "Local/Global" set to "locally admninistered".

   o  Bit "Unicast/Multicast" set to "Unicast".

   o  46 remaining bits set to a random value, using a random number
      generator that meets the requirements of
[https://tools.ietf.org/html/rfc4086].

   The way to meet the randomization requirements is to retain 46 bits
   from the output of a strong hash function, such as SHA256, taking as
   input a 256 bit local secret, the "nominal" MAC Address of the
   interface, and a representation of the date and time of the
   renumbering event.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appen=
dix
-D.  IEEE 802.11 Messages Transmitted in OCB mode


   For information, at the time of writing, this is the list of IEEE
   802.11 messages that may be transmitted in OCB mode, i.e. when
   dot11OCBActivated is true in a STA:

   o  The STA may send management frames of subtype Action and, if the
      STA maintains a TSF Timer, subtype Timing Advertisement;

   o  The STA may send control frames, except those of subtype PS-Poll,
      CF-End, and CF-End plus CFAck;

   o  The STA may send data frames of subtype Data, Null, QoS Data, and
      QoS Null.

Authors' Addresses


------=_NextPart_000_0075_01D32007.19622A40
Content-Type: text/html;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable






RE: [ipwave] Review comments on =
draft-ietf-ipwave-ipv6-over-80211ocb-04.txt





Mr. =
Gundaveli,



I provided some =
comments and responses in the text below your comments identified =
by “[Fygs] and “bold”.



If you have =
additional questions, please, let me know.



Sincerely,






Francois =
Simon



From: its [mailto:its-bounces@ietf.org] On =
Behalf Of Sri Gundavelli (sgundave)



Sent: Sunday, =
August 27, 2017 11:01 PM



To: =
its@ietf.org



Subject: =
[ipwave] Review comments on =
draft-ietf-ipwave-ipv6-over-80211ocb-04.txt





Attached is my =
review feedback.=A0



In general =
there is lot of good information in the document. But, there are also =
few areas where additional clarifications will greatly =
help.



1.) Its not =
clear, if the document makes any assumption on the operating =
environment/communication profile. There is not much discussion on that =
aspect; For example, Is it always a one-hop communication between RSU =
and OBU where the 802.11-OCB link? =A0So, is the use of IPv6 only in =
that context of 1-hop communication?=A0



2.) There is =
also no discussion on how these links get formed in vehicular =
environment and when they are attached/detached.=A0



3.) How do =
nodes discover each other? =A0How does ND resolution work? Are these =
messages received by a multiple RSU’s, or a single RSU? Whats the =
implication of that. Note that you don’t have that issue in =
802.11, given the association to an access point, which in turn maps the =
links to a VLAN/subnet.



4.) What =
happens as a vehicle moves between RSU’s, how does it impact =
address configuration? =A0 Is DHCPv6 based address configuration =
relevant here?





=A0Please see =
inline for additional comments.







--------------------------------------------------------=
----------



 



Transmission of =
IPv6 Packets over IEEE 802.11 Networks in mode Outside



        =




the Context of =
a Basic Service Set (IPv6-over-80211ocb)



         &n=
bsp;    



draft-ietf-ipwave-ipv6-over-80211ocb-04.txt







[Sri] May be =
change to, “..in mode .." —> “..operating in =
mode ..”  ?



[Fygs] =
Agreed





Abstract



   In =
order to transmit IPv6 packets on IEEE 802.11 networks run =
outside



   =
the context of a basic service set (OCB, earlier "802.11p") =
there is



   a =
need to define a few parameters such as the recommended =
Maximum



   =
Transmission Unit size, the header format preceding the IPv6 =
header,



   =
the Type value within it, and others.  This document describes =
these



   =
parameters for IPv6 and IEEE 802.11 OCB networks; it portrays =
the



   =
layering of IPv6 on 802.11 OCB similarly to other known 802.11 =
and



   =
Ethernet layers - by using an Ethernet Adaptation =
Layer.



[Sri] Is it =
“recommended MTU size", or "supported MTU size on the =
802.11 OCB link?  





   In =
addition, the document attempts to list what is different =
in



   =
802.11 OCB (802.11p) compared to more 'traditional' =
802.11a/b/g/n



   =
layers, layers over which IPv6 protocols operates without =
issues.



   =
Most notably, the operation outside the context of a BSS (OCB) =
has



   =
impact on IPv6 handover behaviour and on IPv6 =
security.



[Sri] Minor =
comment. May be instead of using the “layer” terminology, =
you may want to present this as IPv6 support on "802.11 OCB" =
links.



[Fygs] =
802.11 OCB provides data link and PHY services to =
IPv6



 



   An =
example of an IPv6 packet captured while transmitted over an =
IEEE



   =
802.11 OCB link (802.11p) is given.



[Sri] Last =
paragraph can be ommitted in my view. That’s too much of detail =
for Abstract.



[Fygs] - =
Agree






Status of This =
Memo



   =
This Internet-Draft is submitted in full conformance with =
the



   =
provisions of https://tools.ietf.org/html/bc=
p78 and https://tools.ietf.org/html/bc=
p79.



   =
Internet-Drafts are working documents of the Internet =
Engineering



   =
Task Force (IETF).  Note that other groups may also =
distribute







Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 1]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-2



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
working documents as Internet-Drafts.  The list of current =
Internet-



   =
Drafts is at http://datatracker.i=
etf.org/drafts/current/.



   =
Internet-Drafts are draft documents valid for a maximum of six =
months



   =
and may be updated, replaced, or obsoleted by other documents at =
any



   =
time.  It is inappropriate to use Internet-Drafts as =
reference



   =
material or to cite them other than as "work in =
progress."



   =
This Internet-Draft will expire on February 18, 2018.



Copyright =
Notice



   =
Copyright (c) 2017 IETF Trust and the persons identified as =
the



   =
document authors.  All rights reserved.



   =
This document is subject to https://tools.ietf.org/html/bc=
p78 and the IETF Trust's Legal



   =
Provisions Relating to IETF Documents



   =
(http://trustee.ietf.org/lic=
ense-info) in effect on the date of



   =
publication of this document.  Please review these =
documents



   =
carefully, as they describe your rights and restrictions with =
respect



   to =
this document.  Code Components extracted from this document =
must



   =
include Simplified BSD License text as described in Section 4.e =
of



   =
the Trust Legal Provisions and are provided without warranty =
as



   =
described in the Simplified BSD License.



Table of =
Contents



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-1.  Introduction  . . . . . . . . . . . . =
. . . . . . . . . . . .   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-3



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-2.  Terminology . . . . . . . . . . . . . . . =
. . . . . . . . . .   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-5



   =
3.  Communication Scenarios where IEEE 802.11 OCB Links are =
Used    6



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-4.  Aspects introduced by the OCB mode to =
802.11  . . . . . . . .   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-6



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-5.  Layering of IPv6 over 802.11-OCB as over =
Ethernet . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-10



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.1.  Maximum Transmission Unit (MTU) . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-10



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.2.  Frame =
Format  . . . . . . . . . . . . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-11



       https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over=
-80211ocb-04#section-5.2.1.  Ethernet Adaptation Layer . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-12



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.3.  =
Link-Local Addresses  . . . . . . . . . . . =
. . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-13



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.4.  Address Mapping . . . . . . . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-14



       https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over=
-80211ocb-04#section-5.4.1.  Address Mapping -- Unicast  . =
. . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-14



       https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over=
-80211ocb-04#section-5.4.2.  Address Mapping -- Multicast  =
. . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-14



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.5.  Stateless Autoconfiguration . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-15



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.6.  Subnet =
Structure  . . . . . . . . . . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-16



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-6.  Example IPv6 Packet captured over a IEEE 802.11-OCB =
link  . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-16



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-6.1.  Capture in Monitor Mode . . . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-17



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-6.2.  Capture in Normal Mode  . . . . . =
. . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-19



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-7.  Security Considerations . . . . . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-21



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-8.  IANA Considerations . . . . . . . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-22



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-9.  Contributors  . . . . . . . . . . . . =
. . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-22



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#section-10. Acknowledgements  . . . . . . . . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-22







Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 2]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-3



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#section-11. References  . . . . . . . . . . . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-23



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#section-11.1.  Normative References . . . . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-23



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#section-11.2.  Informative References . . . . . . . =
. . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-24



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-A.  ChangeLog  . . . . . . . . . . . . =
. . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-26



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-B.  Changes Needed on a software driver =
802.11a to



         &n=
bsp;      become =
a            =
         802.11-OCB driver . . =
.  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-28



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-C.  Design Considerations  . . . . . . =
. . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-30



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#appendix-C.1.  Vehicle ID  . . . . . . . . . . =
. . . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-30



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#appendix-C.2.  Reliability Requirements  . . . =
. . . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-30



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#appendix-C.3.  Multiple interfaces . . . . . . . . =
. . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-31



     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#appendix-C.4.  MAC Address Generation  . . . . =
. . . . . . . . . . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-32



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-D.  IEEE 802.11 Messages Transmitted in OCB =
mode . . . .  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-32



   =
Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . =
.  https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-32



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-1.  Introduction





   =
This document describes the transmission of IPv6 packets on IEEE =
Std



   =
802.11 OCB networks (earlier known as 802.11p). =A0



[Sri] Please =
add a reference to the IEEE specification that defines the OCB mode. =




[Fygs] Since =
2010 the OCB is defined in IEEE Std 802.11p, IEEE Std 802.11-2012, and =
IEEE 802.11-2016.






This involves =
the



   =
layering of IPv6 networking on top of the IEEE 802.11 MAC layer =
(with



   an =
LLC layer).  Compared to running IPv6 over the Ethernet MAC =
layer,



   =
there is no modification required to the standards: IPv6 works =
fine



   =
directly over 802.11 OCB too (with an LLC layer).



   =
The term "802.11p" is an earlier definition.  As of year =
2012, the



   =
behaviour of "802.11p" networks has been rolled in the =
document IEEE



   =
Std 802.11-2012.  In this document the term 802.11p =
disappears.



   =
Instead, each 802.11p feature is conditioned by a flag in =
the



   =
Management Information Base.  That flag is named =
"OCBActivated".



   =
Whenever OCBActivated is set to true the feature it relates =
to



   =
represents an earlier 802.11p feature.  For example, an =
802.11



   =
STAtion operating outside the context of a basic service set has =
the



   =
OCBActivated flag set.  Such a station, when it has the flag set, =
it



   =
uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.



   In =
the following text we use the term "802.11p" to mean =
802.11-2012



   =
OCB.



   =
The IPv6 network layer operates on 802.11 OCB in the same manner =
as



   it =
operates on 802.11 WiFi, with a few particular exceptions.  =
The



   =
IPv6 network layer operates on WiFi by involving an =
Ethernet



   =
Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 =
headers



   to =
Ethernet II headers.  The operation of IP on Ethernet is =
described



   in =
[https://tools.ietf.org/html/=
rfc1042] and [https://tools.ietf.org/html/=
rfc2464].  The situation of IPv6 networking =
layer



   on =
Ethernet Adaptation Layer is illustrated below:















Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 3]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-4



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





         &n=
bsp;       =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;       =
|            =
     =
IPv6           &nb=
sp;      |



         &n=
bsp;       =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;       =
|       Ethernet Adaptation =
Layer       |



         &n=
bsp;       =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;       =
|            =
 802.11 WiFi =
MAC           =
|



         &n=
bsp;       =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;       =
|            =
 802.11 WiFi =
PHY           =
|



         &n=
bsp;       =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





   =
(in the above figure, a WiFi profile is represented; this is =
used



   =
also for OCB profile.)



   A =
more theoretical and detailed view of layer stacking, =
and



   =
interfaces between the IP layer and 802.11 OCB layers, is =
illustrated



   =
below.  The IP layer operates on top of the EtherType =
Protocol



   =
Discrimination (EPD); this Discrimination layer is described in =
IEEE



   =
Std 802.3-2012; the interface between IPv6 and EPD is the =
LLC_SAP



   =
(Link Layer Control Service Accesss Point).





         &n=
bsp; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp; =
|            =
     =
IPv6           &nb=
sp;      |



         &n=
bsp; =
+-+-+-+-+-+-{          =
  }+-+-+-+-+-+-+-+



         &n=
bsp;           &nb=
sp; {   LLC_SAP  =
}            =
     802.11 OCB



         &n=
bsp; =
+-+-+-+-+-+-{          =
  }+-+-+-+-+-+-+-+  Boundary



         &n=
bsp; |            =
EPD          =
|       |     =
|



         &n=
bsp; =
|            =
             =
| MLME  |     |



         &n=
bsp; +-+-+-{  MAC_SAP   }+-+-+-|  =
MLME_SAP   |



         &n=
bsp; |      MAC =
Sublayer       =
|       |     |  =
802.11 OCB



         &n=
bsp; |     and ch. =
coord.      =
|       | SME |  =
Services



         &n=
bsp; +-+-+-{   PHY_SAP  =
}+-+-+-+-+-+-+-|     |



         &n=
bsp; =
|            =
             =
| PLME  |     |



         &n=
bsp; |            =
PHY Layer    |   PLME_SAP  =
|



         &n=
bsp; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





   In =
addition to the description of interface between IP and MAC =
using



   =
"Ethernet Adaptation Layer" and "Ethernet Protocol =
Discrimination



   =
(EPD)" it is worth mentioning that SNAP [https://tools.ietf.org/html/=
rfc1042] is used to carry



   =
the IPv6 Ethertype.



   =
However, there may be some deployment considerations helping =
optimize



   =
the performances of running IPv6 over 802.11-OCB (e.g. in the case =
of



   =
handovers between 802.11 OCB-enabled access routers, or =
the



   =
consideration of using the IP security layer [https://tools.ietf.org/html/=
rfc4301]).









Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 4]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-5



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
There are currently no specifications for handover between OCB =
links



   =
since these are currently specified as LLC-1 links =
(i.e.



   =
connectionless).  Any handovers must be performed above the Data =
Link



   =
Layer.  Also, while there is no encryption applied below the =
network



   =
layer using 802.11p, 1609.2 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-ove=
r-80211ocb-04#ref-ieee1609.2] does provide =
security



   =
services for applications to use so that there can easily be =
data



   =
security over the air without invoking IPsec.



   We =
briefly introduce the vehicular communication scenarios where =
IEEE



   =
802.11-OCB links are used.=A0



[Sri] I have =
not seen much discussion on the link / communication assumptions. =




[Fygs] Not =
sure of what is meant by assumptions in this =
context.






 This is =
followed by a description of



   =
differences in specification terms, between 802.11 OCB =
and



   =
802.11a/b/g/n (and the same differences expressed in terms =
of



   =
requirements to software implementation are listed in https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-B.)



   =
The document then concentrates on the parameters of layering IP =
over



   =
802.11 OCB as over Ethernet: value of MTU, the contents of =
Frame



   =
Format, the rules for forming Interface Identifiers, the =
mechanism



   =
for Address Mapping and for State-less Address =
Auto-configuration.



   =
These are precisely the same as IPv6 over Ethernet [https://tools.ietf.org/html/=
rfc2464].



   As =
an example, these characteristics of layering IPv6 straight =
over



   =
LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 =
packet



   =
captured over a 802.11 OCB link; this is described in the =
section



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-6.



   A =
couple of points can be considered as different, although they =
are



   =
not required in order to have a working implementation of =
IPv6-over-



   =
802.11-OCB.  These points are consequences of the OCB operation =
which



   is =
particular to 802.11 OCB (Outside the Context of a BSS).  =
First,



   =
the handovers between OCB links need specific behaviour for IP =
Router



   =
Advertisements, or otherwise 802.11 OCB's Time Advertisement, or =
of



   =
higher layer messages such as the 'Basic Safety Message' (in the =
US)



   or =
the 'Cooperative Awareness Message' (in the EU) or the =
'WAVE



   =
Routing Advertisement'; second, the IP security mechanisms =
are



   =
necessary, since OCB means that 802.11 is stripped of all =
802.11



   =
link-layer security; a small additional security aspect which =
is



   =
shared between 802.11 OCB and other 802.11 links is the =
privacy



   =
concerns related to the address formation mechanisms.



   In =
the published literature, many documents describe aspects =
related



   to =
running IPv6 over 802.11 OCB:



   =
[https://tools.ietf.o=
rg/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.jeong-ipwave-vehi=
cular-networking-survey].



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-2.  Terminology





   =
The key words "MUST", "MUST NOT", =
"REQUIRED", "SHALL", "SHALL =
NOT",



   =
"SHOULD", "SHOULD NOT", "RECOMMENDED", =
"MAY", and "OPTIONAL" in this



   =
document are to be interpreted as described in https://tools.ietf.org/html/=
rfc2119 [https://tools.ietf.org/html/=
rfc2119].







Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 5]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-6



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
RSU: Road Side Unit.  A computer equipped with at least one =
IEEE



   =
802.11 interface operated in OCB mode.  This definition applies =
to



   =
this document.  An RSU may be connected to the Internet, and may =
be



   =
equipped with additional wired or wireless network interfaces =
running



   =
IP.  An RSU MAY be an IP Router.





[Sri] RSU can =
be compared to an 802.11 access point; Or, WTP as defined in CAPWAP =
specification, RFC5415.



[Fygs] While =
I am not familiar with “WTP as defined in CAPWAP specification, =
RFC5415”, I know that an RSU has no commonality with an 802.11 =
AP.






Perhaps. =
rephrase as below?:



"RSU: Road =
Side Unit. Its a wireless termination point (WTP), as defined in RFC5415 =
with one key difference, where the wireless physical and the mac layer =
is MAC layers configured to operate in 802.11 OCB mode.=A0 The RSU =
communicates with the On board Unit (OBU) in the vehicle over 802.11 =
wireless link operating in OCB mode.” 



[Fygs]:  This seems reasonable and accurate.  =
This would be for V2I mode.






** Also, since =
you are defining the RSU term, should you also not define OBU (On board =
Unit) in the vehicle which is the entity on the other end of the link? =
“RSU ----802.11-OCB——OBU” ? May be introduce the =
OCB definition separately, just as you did with RSU, and show the =
communication link as 802.11-OCB.



[Fygs] Here =
is a definition of OBU (FCC): “An On-Board Unit is a DSRCS =
transceiver that is normally mounted in or on a vehicle, or which in =
some instances may be a portable unit. An OBU can be operational while a =
vehicle or person is either mobile or =
stationary.”






   =
OCB: outside the context of a basic service set (BSS): A mode =
of



   =
operation in which a STA is not a member of a BSS and does =
not



   =
utilize IEEE Std 802.11 authentication, association, or =
data



   =
confidentiality.



   =
802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that =
is



   =
flagged by "dot11OCBActivated".  This means: IEEE 802.11e =
for quality



   of =
service; 802.11j-2004 for half-clocked operations; and (what =
was



   =
known earlier as) 802.11p for operation in the 5.9 GHz band and =
in



   =
mode OCB.





[Sri] The text =
starting with. “This means” is not clear to me. Does it =
802.11e is supported with 802.11OCB mode. Please =
clarify



[Fygs] QoS is required for 802.11 OCB. 






https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-3.  Communication Scenarios where IEEE 802.11 =
OCB Links are Used





   =
The IEEE 802.11 OCB Networks are used for vehicular =
communications,



   as =
'Wireless Access in Vehicular Environments'.  The IP =
communication



   =
scenarios for these environments have been described in =
several



   =
documents, among which we refer the reader to one recently =
updated



   =
[https://tools.ietf.org/html/draft=
-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.petrescu-its-scenarios-reqs], about scenarios and requirements



   =
for IP in Intelligent Transportation Systems.





[Sri] You can =
do bit more justice to this section.=A0



Explain the =
link model.  “STA ----802.11-OCB——STA”. =
Then talk about the applicability in Vehicular networks, with STA's as =
RSU and OCB.



You may also =
want to talk about, how links get formed/terminated; how nodes =
peer/discover and how mobility works ..etc.  While 802.11-OCB is =
clearly specified and the use of IPv6 over such link is also not =
radically new, but the operating environment which is vehicular brings =
many new things. That description is not present any =
where.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-4.  Aspects introduced by the OCB mode to =
802.11





   In =
the IEEE 802.11 OCB mode, all nodes in the wireless range =
can



   =
directly communicate with each other without =
authentication/



   =
association procedures.  Briefly, the IEEE 802.11 OCB mode has =
the



   =
following properties:





[Sri] Can you =
add some text on how nodes (ST1 and STA2) discover each other on such =
links supporting 802.11 OCB mode.



   =
o  The use by each node of a 'wildcard' BSSID (i.e., each bit of =
the



      BSSID is set to =
1)



   =
o  No IEEE 802.11 Beacon frames transmitted



   =
o  No authentication required



   =
o  No association needed



o       No =
encryption provided






[Fygs] All =
the nodes in the communication range (OBU and =
RSU) =
receives all the messages transmitted (OBU and =
RSU) =
within the communications range. The conflicts are resolved by the MAC CDMA =
function.  =







[Sri] Can you =
clarify what you mean when you say “No xxx required” / =
“No xxx needed”  for the above capabilities.=A0 What =
does “needed” or “required” mean?  Does it =
mean, “Authentication", “Association" and =
“Encryption” is optional on this link, or that its not =
supported on 802.11 OCB links.



[Fygs] The original text in IEEE 802.11p specifies: =




“Change the lettered list items (a) =
through (c) of 5.3.1 as follows:



a) Authentication (not used when =
dot11OCBEnabled is true)



b) =
Deauthentication (not used when dot11OCBEnabled is =
true)



c) Data =
confidentiality (not used when dot11OCBEnabled is =
true)”  



   =
o  Flag dot11OCBActivated set to true



   =
The following message exchange diagram illustrates a =
comparison



   =
between traditional 802.11 and 802.11 in OCB mode.  The =
'Data'







Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 6]



________________________________________


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cb-04#page-7



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
messages can be IP messages such as the messages used in Stateless =
or



   =
Stateful Address Auto-Configuration, or other IP messages. =
=A0





[Sri] Lets =
separate the discussion on IP Address configuration using SLAAC/DHCP on =
such links from the above description. The Data packets here can be =
application packets such as HTTP or other packets. May be additional =
discussion is needed on the IP address configuration on 802.11-OCB =
links. 





Other



   =
802.11 management and control frames (non IP) may be transmitted, =
as



   =
specified in the 802.11 standard.  For information, the names =
of



   =
these messages as currently specified by the 802.11 standard =
are



   =
listed in https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-D.













     =
STA           &nbs=
p;        =
AP            =
;  =
STA1           &nb=
sp;       STA2



     =
|            =
          =
|            =
   =
|            =
          =
|



     |<------ Beacon =
-------|           =
;    |<------ Data -------->|



     =
|            =
          =
|            =
   =
|            =
          =
|



     |---- Probe Req. =
----->|          &nb=
sp;    |<------ Data -------->|



     |<--- Probe Res. =
------|           =
    =
|            =
          =
|



     =
|            =
          =
|            =
   |<------ Data -------->|



     |---- Auth Req. =
------>|          &n=
bsp;    =
|            =
          =
|



     |<--- Auth Res. =
-------|           =
;    |<------ Data -------->|



     =
|            =
          =
|            =
   =
|            =
          =
|



     |---- Asso Req. =
------>|          &n=
bsp;    |<------ Data -------->|



     |<--- Asso Res. =
-------|           =
;    =
|            =
          =
|



     =
|            =
          =
|            =
   |<------ Data -------->|



     |<------ Data =
-------->|          =
     =
|            =
          =
|



     |<------ Data =
-------->|          =
     |<------ Data =
-------->|



    (a) 802.11 Infrastructure =
mode         (b) 802.11 OCB =
mode





   =
The link 802.11 OCB was specified in IEEE Std 802.11p (TM) =
-2010



   =
[https://tools.ietf.org/html/draft-ietf-ipwave-ip=
v6-over-80211ocb-04#ref-ieee802.11p-2010] as an amendment to IEEE =
Std 802.11 (TM) -2007,



   =
titled "Amendment 6: Wireless Access in Vehicular =
Environments".



   =
Since then, this amendment has been included in IEEE =
802.11(TM)-2012



   =
[https://tools.ietf.org/html/draft-ietf-ipwave-ipv=
6-over-80211ocb-04#ref-ieee802.11-2012], titled "IEEE Standard =
for Information technology--



   =
Telecommunications and information exchange between systems Local =
and



   =
metropolitan area networks--Specific requirements Part 11: =
Wireless



   =
LAN Medium Access Control (MAC) and Physical Layer =
(PHY)



   =
Specifications"; the modifications are diffused throughout =
various



   =
sections (e.g. the Time Advertisement message described in =
the



   =
earlier 802.11 (TM) p amendment is now described in section =
'Frame



   =
formats', and the operation outside the context of a BSS described =
in



   =
section 'MLME').



   In =
document 802.11-2012, specifically anything referring



   =
"OCBActivated", or "outside the context of a basic =
service set" is



   =
actually referring to the 802.11p aspects introduced to 802.11.  =
Note



   =
that in earlier 802.11p documents the term "OCBEnabled" was =
used



   =
instead of te current "OCBActivated".











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 7]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-8



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   In =
order to delineate the aspects introduced by 802.11 OCB to =
802.11,



   we =
refer to the earlier [https://tools.ietf.org/html/draft-ietf-ipwave-ip=
v6-over-80211ocb-04#ref-ieee802.11p-2010].  The amendment =
is



   =
concerned with vehicular communications, where the wireless link =
is



   =
similar to that of Wireless LAN (using a PHY layer specified =
by



   =
802.11a/b/g/n), but which needs to cope with the high mobility =
factor



   =
inherent in scenarios of communications between moving vehicles, =
and



   =
between vehicles and fixed infrastructure deployed along =
roads.



   =
While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' =
is



   =
concerned more with MAC modifications, and a little with =
PHY



   =
modifications; the others are mainly about PHY modifications.  It =
is



   =
possible in practice to combine a 'p' MAC with an 'a' PHY =
by



   =
operating outside the context of a BSS with OFDM at =
5.4GHz.



   =
The 802.11 OCB links are specified to be compatible as much =
as



   =
possible with the behaviour of 802.11a/b/g/n and future =
generation



   =
IEEE WLAN links.  From the IP perspective, an 802.11 OCB MAC =
layer



   =
offers practically the same interface to IP as the WiFi and =
Ethernet



   =
layers do (802.11a/b/g/n and 802.3).





[Sri] A packet =
sent from a vehicle’s OBU is received by a single RSU, or multiple =
RSU’s? How does the link-layer resolution =
happen?



[Fygs] =
Assuming that:



a)      If there are =
single or multiple =
RSUs in the communication range and it is =
a multicast message, the single RSU =
or RSUs =
in the comm. range will receive it =
(eventually). There is no resolution at the link layer. The =
RSU(s) will determine their “interest” based =
on the =
content of the message at the higher layers =
(application);



b)      If there are single or =
multiple RSUs in the communication rand and it is unicast message, then the =
link-layer resolves by the =
destination MAC =
address.


    

    






   To =
support this similarity statement (IPv6 is layered on top of =
LLC



   on =
top of 802.11 OCB similarly as on top of LLC on top of



   =
802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful =
to



   =
analyze the differences between 802.11 OCB and 802.11 =
specifications.



   =
Whereas the 802.11p amendment specifies relatively complex =
and



   =
numerous changes to the MAC layer (and very little to the PHY =
layer),



   we =
note there are only a few characteristics which may be =
important



   =
for an implementation transmitting IPv6 packets on 802.11 OCB =
links.



   In =
the list below, the only 802.11 OCB fundamental points =
which



   =
influence IPv6 are the OCB operation and the 12Mbit/s maximum =
which



   =
may be afforded by the IPv6 applications.





[Sri] I am =
really not sure how link throughput (12Mbps) relates to "IPv6 =
support on OCB links". =




[Fygs] First of all there is guarantee of 12 Mbps =
throughput because of collisions and other interferences, 12 Mbps data =
rate was probably intended.



The data rates for 20 MHz channel =
spacing are 6, 9, 12, 18, 24, =
36, 48, and 54 =
Mb/s with mandatory support of 6, 12, and 24 =
Mbps;



Data rates =
for 10 MHz channel spacing are 3, 4.5, 6, 9, 12, 18, 24, and =
27 Mb/s. with mandatory support of  3, 6, and 12 =
Mb/s. 





   =
o  Operation Outside the Context of a BSS (OCB): the =
(earlier



      802.11p) 802.11-OCB =
links are operated without a Basic Service Set



      (BSS).  This means =
that the frames IEEE 802.11 Beacon, Association



      Request/Response, =
Authentication Request/Response, and similar,



      are not used.  The =
used identifier of BSS (BSSID) has a



      hexadecimal value always =
0xffffffffffff (48 '1' bits, represented



      as MAC address =
ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'



      BSSID), as opposed to an =
arbitrary BSSID value set by



      administrator =
(e.g.  'My-Home-AccessPoint').  The OCB operation =
-



      namely the lack of =
beacon-based scanning and lack of



      authentication - has a =
potentially strong impact on the use of the



      Mobile IPv6 protocol [https://tools.ietf.org/html/=
rfc6275] and on the protocols for IP layer



      security [https://tools.ietf.org/html/=
rfc4301].





[Sri] The =
document till now has been arguing heavily on how IPv6 operates so =
naturally on these links and now I see discussion on “Impact to a =
high-level protocol such as MIPv6”. You may want to fix the =
earlier text. In any case,  the absence of link-layer security =
practically impacts every application, not just MIPv6.  Also, MIPv6 =
does not make any assumptions on the link-layer security.  Also, =
the the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes the messages readable by =
all other RSU’s in proximity. I think the discussion on the nature =
of the link, who all see’s the messages.. how L2 addresses are =
resolved is not explained clearly. 







   =
o  Timing Advertisement: is a new message defined in =
802.11-OCB,



      which does not exist in =
802.11a/b/g/n.  This message is used by







Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 8]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#page-9



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





      stations to inform other =
stations about the value of time.  It is



      similar to the time as =
delivered by a GNSS system (Galileo, GPS,



      ...) or by a cellular =
system.  This message is optional for



      implementation.  At =
the date of writing, an experienced reviewer



      considers that currently =
no field testing has used this message.



      Another implementor =
considers this feature implemented in an



      initial manner.  In =
the future, it is speculated that this message



      may be useful for very =
simple devices which may not have their own



      hardware source of time =
(Galileo, GPS, cellular network), or by



      vehicular devices =
situated in areas not covered by such network



      (in tunnels, =
underground, outdoors but shaded by foliage or



      buildings, in remote =
areas, etc.)





[Sri] The first =
part explaining Timing Advertisement messages is great, but the rest of =
the commentary is unnecessary and not needed. We don’t speculate =
the protocol adoption success in IETF specifications, or about the =
experience level of the “reviewer" :)



[Fygs]: Absolutely agree.






   =
o  Frequency range: this is a characteristic of the PHY layer, =
with



      almost no impact to the =
interface between MAC and IP.  However, it



      is worth considering =
that the frequency range is regulated by a



      regional authority =
(ARCEP, ETSI, FCC, etc.); as part of the



      regulation process, =
specific applications are associated with



      specific frequency =
ranges.  In the case of 802.11-OCB, the



      regulator associates a =
set of frequency ranges, or slots within a



      band, to the use of =
applications of vehicular communications, in a



      band known as =
"5.9GHz".  This band is "5.9GHz" which is =
different



      from the bands =
"2.4GHz" or "5GHz" used by Wireless LAN.  =
However,



      as with Wireless LAN, =
the operation of 802.11-OCB in "5.9GHz"



      bands is exempt from =
owning a license in EU (in US the 5.9GHz is a



      licensed band of =
spectrum; for the the fixed infrastructure an



      explicit FCC =
autorization is required; for an onboard device a



      'licensed-by-rule' =
concept applies: rule certification conformity



      is required); however =
technical conditions are different than



      those of the bands =
"2.4GHz" or "5GHz".  On one hand, the =
allowed



      power levels, and =
implicitly the maximum allowed distance between



      vehicles, is of 33dBm =
for 802.11-OCB (in Europe), compared to 20



      dBm for Wireless LAN =
802.11a/b/g/n; this leads to a maximum



      distance of =
approximately 1km, compared to approximately 50m.  =
On



      the other hand, specific =
conditions related to congestion



      avoidance, jamming =
avoidance, and radar detection are imposed on



      the use of DSRC (in US) =
and on the use of frequencies for



      Intelligent =
Transportation Systems (in EU), compared to Wireless



      LAN =
(802.11a/b/g/n).



   =
o  Prohibition of IPv6 on some channels relevant for IEEE =
802.11-OCB,



      as opposed to IPv6 not =
being prohibited on any channel on which



      802.11a/b/g/n =
runs:



      *  Some channels =
are reserved for safety communications; the IPv6



         =
packets should not be sent on these channels.











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;   [Page 9]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-10



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





      *  At the time of =
writing, the prohibition is explicit at higher



         layer =
protocols providing services to the application; these



         higher =
layer protocols are specified in IEEE 1609 documents.



      *  National or =
regional specifications and regulations specify the



         use of =
different channels; these regulations must be =
followed.



   =
o  'Half-rate' encoding: as the frequency range, this parameter =
is



      related to PHY, and thus =
has not much impact on the interface



      between the IP layer and =
the MAC layer.



   =
o  In vehicular communications using 802.11-OCB links, there =
are



      strong privacy =
requirements with respect to addressing.  While =
the



      802.11-OCB standard does =
not specify anything in particular with



      respect to MAC =
addresses, in these settings there exists a strong



      need for dynamic change =
of these addresses (as opposed to the non-



      vehicular settings - =
real wall protection - where fixed MAC



      addresses do not =
currently pose some privacy risks).  This is



      further described in =
section https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-7.  A relevant function is



      described in IEEE =
1609.3-2016 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-ove=
r-80211ocb-04#ref-ieee1609.3], clause 5.5.1 and =
IEEE



      1609.4-2016 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-ove=
r-80211ocb-04#ref-ieee1609.4], clause 6.7.



   =
Other aspects particular to 802.11-OCB which are also particular =
to



   =
802.11 (e.g. the 'hidden node' operation) may have an influence =
on



   =
the use of transmission of IPv6 packets on 802.11-OCB networks.  =
The



   =
subnet structure which may be assumed in 802.11-OCB networks =
is



   =
strongly influenced by the mobility of vehicles.





[Sri] Per my =
earlier comment, the link model, addressing ..etc needs to be explained =
in more detail. It is not clear what exactly the “subnet =
structure” that is assumed in 802.11-OCB.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-5.  Layering of IPv6 over 802.11-OCB as over =
Ethernet





https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.1.  Maximum Transmission Unit =
(MTU)





   =
The default MTU for IP packets on 802.11-OCB is 1500 octets.  It =
is



   =
the same value as IPv6 packets on Ethernet links, as specified =
in



   =
[https://tools.ietf.org/html/=
rfc2464].  This value of the MTU respects the recommendation =
that



   =
every link in the Internet must have a minimum MTU of 1280 =
octets



   =
(stated in [https://tools.ietf.org/html/=
rfc2460], and the recommendations therein, =
especially



   =
with respect to fragmentation).  If IPv6 packets of size larger =
than



   =
1500 bytes are sent on an 802.11-OCB interface card then the IP =
stack



   =
will fragment.  In case there are IP fragments, the field =
"Sequence



   =
number" of the 802.11 Data header containing the IP fragment field =
is



   =
increased.



   =
Non-IP packets such as WAVE Short Message Protocol (WSMP) can =
be



   =
delivered on 802.11-OCB links.  Specifications of these packets =
are



   =
out of scope of this document, and do not impose any limit on the =
MTU



   =
size, allowing an arbitrary number of 'containers'.  Non-IP =
packets



   =
such as ETSI 'geonet' packets have an MTU of 1492 =
bytes.







Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 10]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-11



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
The Equivalent Transmit Time on Channel is a concept that may be =
used



   as =
an alternative to the MTU concept.  A rate of transmission may =
be



   =
specified as well.  The ETTC, rate and MTU may be in =
direct



   =
relationship.



[Sri] The last =
paragraph needs some additional context. Did 802.11-OCB introduce ETTC =
concept?



[Fygs] NO =
!  =









https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.2.  Frame Format





   IP =
packets are transmitted over 802.11-OCB as standard =
Ethernet



   =
packets.  As with all 802.11 frames, an Ethernet adaptation layer =
is



   =
used with 802.11-OCB as well.  This Ethernet Adaptation =
Layer



   =
performing 802.11-to-Ethernet is described in https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over=
-80211ocb-04#section-5.2.1.  The



   =
Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal =
86DD,



   or =
otherwise #86DD).



   =
The Frame format for transmitting IPv6 on 802.11-OCB networks is =
the



   =
same as transmitting IPv6 on Ethernet networks, and is described =
in



   https://tools.ietf=
.org/html/rfc2464#section-3.  The frame format for transmitting =
IPv6



   =
packets over Ethernet is illustrated below:





         &n=
bsp;          =
0            =
       1



         &n=
bsp;          0 1 2 3 4 5 6 =
7 8 9 0 1 2 3 4 5



         &n=
bsp;          =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;          =
|          =
Destination          =
|



         &n=
bsp;          =
+-            =
;            =
     -+



         &n=
bsp;          =
|            =
Ethernet           =
|



         &n=
bsp;          =
+-            =
;            =
     -+



         &n=
bsp;          =
|            =
Address           =
 |



         &n=
bsp;          =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;          =
|            =
 =
Source            =
|



         &n=
bsp;          =
+-            =
;            =
     -+



         &n=
bsp;          =
|            =
Ethernet           =
|



         &n=
bsp;          =
+-            =
;            =
     -+



         &n=
bsp;          =
|            =
Address           =
 |



         &n=
bsp;          =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;          |1 0 0 0 0 1 =
1 0 1 1 0 1 1 1 0 1|



         &n=
bsp;          =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;          =
|            =
 =
IPv6           &nb=
sp;  |



         &n=
bsp;          =
+-            =
;            =
     -+



         &n=
bsp;          =
|            =
header           &=
nbsp; |



         &n=
bsp;          =
+-            =
;            =
     -+



         &n=
bsp;          =
|            =
 =
and           &nbs=
p;   |



         &n=
bsp;          =
+-            =
;            =
     -+



         &n=
bsp;          =
/            =
payload ...        =
/



         &n=
bsp;          =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;          (Each tic =
mark represents one bit.)











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 11]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-12



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
Ethernet II Fields:



   =
Destination Ethernet Address



      the MAC destination =
address.



   =
Source Ethernet Address



      the MAC source =
address.



   1 =
0 0 0 0 1 1 0 1 1 0 1 1 1 0 1



      binary representation of =
the EtherType value 0x86DD.



   =
IPv6 header and payload



      the IPv6 packet =
containing IPv6 header and payload.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over=
-80211ocb-04#section-5.2.1.  Ethernet Adaptation =
Layer





   In =
general, an 'adaptation' layer is inserted between a MAC layer =
and



   =
the Networking layer.  This is used to transform some =
parameters



   =
between their form expected by the IP stack and the form provided =
by



   =
the MAC layer.  For example, an 802.15.4 adaptation layer may =
perform



   =
fragmentation and reassembly operations on a MAC whose maximum =
Packet



   =
Data Unit size is smaller than the minimum MTU recognized by the =
IPv6



   =
Networking layer.  Other examples involve link-layer =
address



   =
transformation, packet header insertion/removal, and so =
on.



   An =
Ethernet Adaptation Layer makes an 802.11 MAC look to =
IP



   =
Networking layer as a more traditional Ethernet layer.  At =
reception,



   =
this layer takes as input the IEEE 802.11 Data Header and =
the



   =
Logical-Link Layer Control Header and produces an Ethernet II =
Header.



   At =
sending, the reverse operation is performed.





 +--------------------+------------+-------------+-=
--------+-----------+



 | 802.11 =
Data Header | LLC Header | IPv6 Header | Payload |.11 =
Trailer|



 +--------------------+------------+-------------+-=
--------+-----------+



  =
\            =
            &=
nbsp;      =
/            =
             =
\         /



    =
-----------------------------       &n=
bsp;           &nb=
sp;         =
--------



         &n=
bsp;         =
^---------------------------------------------/



         &n=
bsp;         |



         &n=
bsp; 802.11-to-Ethernet Adaptation Layer



         &n=
bsp;         |



         &n=
bsp;         v



 +---------------------+-------------+---------+



 | =
Ethernet II Header  | IPv6 Header | Payload |



 +---------------------+-------------+---------+













Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 12]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-13



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
The Receiver and Transmitter Address fields in the 802.11 Data =
Header



   =
contain the same values as the Destination and the Source =
Address



   =
fields in the Ethernet II Header, respectively.  The value of =
the



   =
Type field in the LLC Header is the same as the value of the =
Type



   =
field in the Ethernet II Header.



   =
The ".11 Trailer" contains solely a 4-byte Frame Check =
Sequence.



   =
The Ethernet Adaptation Layer performs operations in relation to =
IP



   =
fragmentation and MTU.  One of these operations is briefly =
described



   in =
section https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.1.



   In =
OCB mode, IPv6 packets can be transmitted either as "IEEE =
802.11



   =
Data" or alternatively as "IEEE 802.11 QoS Data", as =
illustrated in



   =
the following figure:





+--------------------+-------------+-------------+------=
---+-----------+



| 802.11 Data =
Header | LLC Header  | IPv6 Header | Payload |.11 =
Trailer|



+--------------------+-------------+-------------+------=
---+-----------+



or



+--------------------+-------------+-------------+------=
---+-----------+



| 802.11 QoS =
Data Hdr| LLC Header  | IPv6 Header | Payload |.11 =
Trailer|



+--------------------+-------------+-------------+------=
---+-----------+





   =
The distinction between the two formats is given by the value of =
the



   =
field "Type/Subtype".  The value of the field =
"Type/Subtype" in the



   =
802.11 Data header is 0x0020.  The value of the field =
"Type/Subtype"



   in =
the 802.11 QoS header is 0x0028.



   =
The mapping between qos-related fields in the IPv6 header =
(e.g.



   =
"Traffic Class", "Flow label") and fields in the =
"802.11 QoS Data



   =
Header" (e.g.  "QoS Control") are not specified in =
this document.



   =
Guidance for a potential mapping is provided in



   =
[https://tools.ietf.org/html/draft-ietf=
-ipwave-ipv6-over-80211ocb-04#ref-I-D.ietf-tsvwg-ieee-802-11], =
although it is not specific to OCB



   =
mode.







[Sri] The =
applicability of the QoS mapping draft to 802.11-OCB needs further =
investigation, IMO.



[Fygs] I am not familiar with =
QoS control of IPv6.  As for the OCB MAC QoS it is somewhat =
involved.  It is based =
on transmission priority of MAC frames.  A higher priority frame is =
intended to be transmitted ahead of lower priority =
frames.  If a detail process is =
required, please, let me know and I would provide the =
text.








https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.3.  Link-Local Addresses





   =
The link-local address of an 802.11-OCB interface is formed in =
the



   =
same manner as on an Ethernet interface.  This manner is described =
in



   https://tools.ietf=
.org/html/rfc2464#section-5.







[Sri] Does this =
go against the 8064 recommendation on Interface identifier =
generation?



May be RFC7217 =
for interface identifier generation in conjunction with the link-local =
address generation per RFC2464











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 13]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-14



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.4.  Address Mapping





   =
For unicast as for multicast, there is no change from the unicast =
and



   =
multicast address mapping format of Ethernet interfaces, as =
defined



   by =
sections https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-6 and https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-7 of [https://tools.ietf.org/html/=
rfc2464].







[Sri] RFC6085 =
specified mapping is also relevant; If the communication peers are aware =
that there is only one peer, it should apply 6085 specified mapping. =
That mode is relevant for 802.11-OCB types links as =
well.





https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over=
-80211ocb-04#section-5.4.1.  Address Mapping -- =
Unicast





   =
The procedure for mapping IPv6 unicast addresses into Ethernet =
link-



   =
layer addresses is described in [https://tools.ietf.org/html/=
rfc4861].  The Source/Target Link-



   =
layer Address option has the following form when the link-layer =
is



   =
Ethernet.



[Sri] I =
thought, mapping of IPv6 unicast addresses to Ethernet link-layer =
addresses is specified in section 6, of RFC2464 and not in =
RFC4861.







         &n=
bsp;            =
0            =
       1



         &n=
bsp;            0 =
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5



         &n=
bsp;           =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;           =
|     Type      =
|    Length     |



         &n=
bsp;           =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;           =
|            =
            &=
nbsp;      |



         &n=
bsp;           =
+-          =
Ethernet           =
-+



         &n=
bsp;           =
|            =
            &=
nbsp;      |



         &n=
bsp;           =
+-           =
Address           =
-+



         &n=
bsp;           =
|            =
            &=
nbsp;      |



         &n=
bsp;           =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





   =
Option fields:



   =
Type



      1 for Source Link-layer =
address.



      2 for Target Link-layer =
address.



   =
Length



      1 (in units of 8 =
octets).



   =
Ethernet Address



      The 48 bit Ethernet IEEE =
802 address, in canonical bit order.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over=
-80211ocb-04#section-5.4.2.  Address Mapping -- =
Multicast





   =
IPv6 protocols often make use of IPv6 multicast addresses in =
the



   =
destination field of IPv6 headers.  For example, an ICMPv6 =
link-



   =
scoped Neighbor Advertisement is sent to the IPv6 address =
ff02::1



   =
denoted "all-nodes" address.  When transmitting these =
packets on



   =
802.11-OCB links it is necessary to map the IPv6 address to a =
MAC



   =
address.









Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 14]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-15



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
The same mapping requirement applies to the link-scoped =
multicast



   =
addresses of other IPv6 protocols as well.  In DHCPv6, =
the



   =
"All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in =
OSPF the



   =
"All_SPF_Routers" IPv6 multicast address ff02::5, need to be =
mapped



   on =
a multicast MAC address.



   An =
IPv6 packet with a multicast destination address DST, =
consisting



   of =
the sixteen octets DST[1] through DST[16], is transmitted to =
the



   =
IEEE 802.11-OCB MAC multicast address whose first two octets are =
the



   =
value 0x3333 and whose last four octets are the last four octets =
of



   =
DST.



[Sri] Please =
add a reference to Section 7, RFC4861 and also RFC6085. In general, for =
both unicast and multicast, you may want to clearly say that this is per =
the existing specs and duplicated here for convenience. =




         &n=
bsp;           =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;           |0 0 1 =
1 0 0 1 1|0 0 1 1 0 0 1 1|



         &n=
bsp;           =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;           =
|   DST[13]     |   =
DST[14]     |



         &n=
bsp;           =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         &n=
bsp;           =
|   DST[15]     |   =
DST[16]     |



         &n=
bsp;           =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





   A =
Group ID TBD of length 112bits may be requested from IANA; =
this



   =
Group ID signifies "All 80211OCB Interfaces Address".  =
Only the least



   32 =
significant bits of this "All 80211OCB Interfaces Address" =
will be



   =
mapped to and from a MAC multicast address.



   =
Transmitting IPv6 packets to multicast destinations over 802.11 =
links



   =
proved to have some performance issues



   =
[https://tools.ietf.org/html=
/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.perkins-intarea-multicas=
t-ieee802].  These issues may be



   =
exacerbated in OCB mode.  Solutions for these problems =
should



   =
consider the OCB mode of operation.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.5.  Stateless =
Autoconfiguration





   =
The Interface Identifier for an 802.11-OCB interface is formed =
using



   =
the same rules as the Interface Identifier for an Ethernet =
interface;



   =
this is described in https://tools.ietf=
.org/html/rfc2464#section-4.  No changes are =
needed,



   =
but some care must be taken when considering the use of the =
SLAAC



   =
procedure.





[Sri] Per my =
earlier comment, please refer to the current recommendation on =
interface-identifier generation and its use in link-local, global or =
other addresses.





   =
The bits in the the interface identifier have no generic meaning =
and



   =
the identifier should be treated as an opaque value.  The =
bits



   =
'Universal' and 'Group' in the identifier of an 802.11-OCB =
interface



   =
are significant, as this is an IEEE link-layer address.  The =
details



   of =
this significance are described in [https://tools.ietf.org/html/draft-ietf-ipwave-ip=
v6-over-80211ocb-04#ref-I-D.ietf-6man-ug].











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 15]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-16



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   As =
with all Ethernet and 802.11 interface identifiers ([https://tools.ietf.org/html/=
rfc7721]),



   =
the identifier of an 802.11-OCB interface may involve privacy =
risks.



   A =
vehicle embarking an On-Board Unit whose egress interface =
is



   =
802.11-OCB may expose itself to eavesdropping and =
subsequent



   =
correlation of data; this may reveal data considered private by =
the



   =
vehicle owner; there is a risk of being tracked; see the =
privacy



   =
considerations described in https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-C.





[Sri] I think =
there are other security issues here; the absence of link-layer security =
opens up Mac-spoofing and IP address hijacking.  That should be =
mentioned.





   If =
stable Interface Identifiers are needed in order to form =
IPv6



   =
addresses on 802.11-OCB links, it is recommended to follow =
the



   =
recommendation in [https://tools.ietf.org/html/draft-ietf=
-ipwave-ipv6-over-80211ocb-04#ref-I-D.ietf-6man-default-iids].=




https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-5.6.  Subnet Structure





   =
The 802.11 networks in OCB mode may be considered as =
'ad-hoc'



   =
networks.  The addressing model for such networks is described =
in



   =
[https://tools.ietf.org/html/=
rfc5889].





[Sri] Per my =
earlier comment, there is no system level view of the network where =
802.11-OCB links are used. So, in the absence of such discussion So, I =
am not sure what part of RFC5889 is applicable here. For example, =
link-local addresses may just work fine. 





https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-6.  Example IPv6 Packet captured over a IEEE =
802.11-OCB link





   We =
remind that a main goal of this document is to make the case =
that



   =
IPv6 works fine over 802.11-OCB networks.  Consequently, this =
section



   is =
an illustration of this concept and thus can help the =
implementer



   =
when it comes to running IPv6 over IEEE 802.11-OCB.  By way =
of



   =
example we show that there is no modification in the headers =
when



   =
transmitted over 802.11-OCB networks - they are transmitted like =
any



   =
other 802.11 and Ethernet packets.



   We =
describe an experiment of capturing an IPv6 packet on =
an



   =
802.11-OCB link.  In this experiment, the packet is an IPv6 =
Router



   =
Advertisement.  This packet is emitted by a Router on its =
802.11-OCB



   =
interface.  The packet is captured on the Host, using a =
network



   =
protocol analyzer (e.g.  Wireshark); the capture is performed in =
two



   =
different modes: direct mode and 'monitor' mode.  The topology =
used



   =
during the capture is depicted below.





         &n=
bsp;    =
+--------+          &nb=
sp;           &nbs=
p;         =
+-------+



         &n=
bsp;    |        =
|        802.11-OCB =
Link         =
|       |



         &n=
bsp; ---| Router |--------------------------------| Host  =
|



         &n=
bsp;    |        =
|            =
            &=
nbsp;       =
|       |



         &n=
bsp;    =
+--------+          &nb=
sp;           &nbs=
p;         =
+-------+





   =
During several capture operations running from a few moments =
to



   =
several hours, no message relevant to the BSSID contexts =
were



   =
captured (no Association Request/Response, Authentication =
Req/Resp,









Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 16]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-17



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
Beacon).  This shows that the operation of 802.11-OCB is outside =
the



   =
context of a BSSID.



   =
Overall, the captured message is identical with a capture of an =
IPv6



   =
packet emitted on a 802.11b interface.  The contents are =
precisely



   =
similar.





[Sri] I suggest =
moving this discussion under the section “Implementation =
Status”, which will eventually be removed from the RFC. There is =
nothing new here. This are details on experimentation. But, if you think =
there is some useful information  such as discussion on Capture =
mode ..etc, you may want to move this entire section to Appendix. =
Implementors may use these tools for verification.







https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-6.1.  Capture in Monitor =
Mode





   =
The IPv6 RA packet captured in monitor mode is illustrated =
below.



   =
The radio tap header provides more flexibility for reporting =
the



   =
characteristics of frames.  The Radiotap Header is prepended by =
this



   =
particular stack and operating system on the Host machine to the =
RA



   =
packet received from the network (the Radiotap Header is not =
present



   on =
the air).  The implementation-dependent Radiotap Header is =
useful



   =
for piggybacking PHY information from the chip's registers as data =
in



   a =
packet understandable by userland applications using =
Socket



   =
interfaces (the PHY interface can be, for example: power levels, =
data



   =
rate, ratio of signal to noise).



   =
The packet present on the air is formed by IEEE 802.11 Data =
Header,



   =
Logical Link Control Header, IPv6 Base Header and ICMPv6 =
Header.







     Radiotap Header =
v0



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     |Header Revision|  Header =
Pad   |    Header =
length           &=
nbsp;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
             =
Present =
flags           &n=
bsp;           &nb=
sp; |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     | Data =
Rate     =
|            =
 =
Pad           &nbs=
p;            =
;       |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     IEEE 802.11 Data =
Header



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     |  Type/Subtype and Frame =
Ctrl  |          =
Duration           =
;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
          Receiver =
Address...



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     ... Receiver =
Address           =
|      Transmitter Address...



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     ... Transmitter =
Address           =
            &=
nbsp;           &n=
bsp;    |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
            &=
nbsp;   BSS Id...



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     ... BSS =
Id            =
;         |  Frag Number =
and Seq Number   |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>







Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 17]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-18



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





     Logical-Link Control =
Header



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|      DSAP   =
|I|     SSAP    |C| Control field | =
Org. code...



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     ... Organizational =
Code        =
|            =
 =
Type           &nb=
sp;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     IPv6 Base =
Header



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     |Version| Traffic Class =
|           Flow =
Label           &n=
bsp;      |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|         Payload =
Length        |  Next =
Header  |   Hop Limit   |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  +



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
             =
Source =
Address           =
             =
+



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  +



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  +



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
          Destination =
Address           =
           =
+



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  +



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     Router =
Advertisement



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     |     =
Type      |     =
Code      =
|          =
Checksum           =
;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     | Cur Hop Limit |M|O|  =
Reserved |       Router =
Lifetime         =
|



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
             =
Reachable =
Time           &nb=
sp;            =
|



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
            &=
nbsp; Retrans =
Timer           &n=
bsp;            =
|



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     |   Options =
...



     =
+-+-+-+-+-+-+-+-+-+-+-+-





   =
The value of the Data Rate field in the Radiotap header is set to =
6



   =
Mb/s.  This indicates the rate at which this RA was =
received.











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 18]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-19



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
The value of the Transmitter address in the IEEE 802.11 Data =
Header



   is =
set to a 48bit value.  The value of the destination address =
is



   =
33:33:00:00:00:1 (all-nodes multicast address).  The value of the =
BSS



   Id =
field is ff:ff:ff:ff:ff:ff, which is recognized by the =
network



   =
protocol analyzer as being "broadcast".  The Fragment =
number and



   =
sequence number fields are together set to 0x90C6.



   =
The value of the Organization Code field in the Logical-Link =
Control



   =
Header is set to 0x0, recognized as "Encapsulated =
Ethernet".  The



   =
value of the Type field is 0x86DD (hexadecimal 86DD, or =
otherwise



   =
#86DD), recognized as "IPv6".



   A =
Router Advertisement is periodically sent by the router =
to



   =
multicast group address ff02::1.  It is an icmp packet type =
134.  The



   =
IPv6 Neighbor Discovery's Router Advertisement message contains =
an



   =
8-bit field reserved for single-bit flags, as described in [https://tools.ietf.org/html/=
rfc4861].



   =
The IPv6 header contains the link local address of the =
router



   =
(source) configured via EUI-64 algorithm, and destination address =
set



   to =
ff02::1.  Recent versions of network protocol analyzers =
(e.g.



   =
Wireshark) provide additional informations for an IP address, if =
a



   =
geolocalization database is present.  In this example, =
the



   =
geolocalization database is absent, and the "GeoIP" =
information is



   =
set to unknown for both source and destination addresses =
(although



   =
the IPv6 source and destination addresses are set to useful =
values).



   =
This "GeoIP" can be a useful information to look up the =
city,



   =
country, AS number, and other information for an IP =
address.



[Sri] Not sure, =
why all of this text should be in the specification. 



   =
The Ethernet Type field in the logical-link control header is set =
to



   =
0x86dd which indicates that the frame transports an IPv6 packet.  =
In



   =
the IEEE 802.11 data, the destination address is =
33:33:00:00:00:01



   =
which is he corresponding multicast MAC address.  The BSS id is =
a



   =
broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short =
link



   =
duration between vehicles and the roadside infrastructure, there =
is



   no =
need in IEEE 802.11-OCB to wait for the completion of =
association



   =
and authentication procedures before exchanging data.  =
IEEE



   =
802.11-OCB enabled nodes use the wildcard BSSID (a value of all =
1s)



   =
and may start communicating as soon as they arrive on =
the



   communication channel.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8=
0211ocb-04#section-6.2.  =
Capture in Normal Mode





   =
The same IPv6 Router Advertisement packet described above =
(monitor



   =
mode) is captured on the Host, in the Normal mode, and =
depicted



   =
below.













Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 19]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-20



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





     Ethernet =
II Header



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
           =
Destination...



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
...Destination          =
;       =
|           =
Source...



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
...Source          &nbs=
p;            =
;            =
            &=
nbsp;      |



     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+



     =
|          =
Type           &nb=
sp;     |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



     IPv6 Base =
Header



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     |Version| Traffic Class =
|           Flow =
Label           &n=
bsp;      |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|         Payload =
Length        |  Next =
Header  |   Hop Limit   |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  +



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
             =
Source =
Address           =
             =
+



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  +



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  +



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
          Destination =
Address           =
           =
+



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  +



     =
|            =
            &=
nbsp;           &n=
bsp;           &nb=
sp;           &nbs=
p;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     Router =
Advertisement



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     |     =
Type      |     =
Code      =
|          =
Checksum           =
;  |



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     | Cur Hop Limit |M|O|  =
Reserved |       Router =
Lifetime         =
|



     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+



     =
|            =
             =
Reachable =
Time           &nb=
sp;            =
|



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     =
|            =
            &=
nbsp; Retrans =
Timer           &n=
bsp;            =
|



     =
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<=
/SPAN>



     |   Options =
...



     =
+-+-+-+-+-+-+-+-+-+-+-+-











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 20]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-21



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
One notices that the Radiotap Header is not prepended, and that =
the



   =
IEEE 802.11 Data Header and the Logical-Link Control Headers are =
not



   =
present.  On another hand, a new header named Ethernet II Header =
is



   =
present.



   =
The Destination and Source addresses in the Ethernet II =
header



   =
contain the same values as the fields Receiver Address =
and



   =
Transmitter Address present in the IEEE 802.11 Data Header in =
the



   =
"monitor" mode capture.



   =
The value of the Type field in the Ethernet II header is =
0x86DD



   =
(recognized as "IPv6"); this value is the same value as the =
value of



   =
the field Type in the Logical-Link Control Header in the =
"monitor"



   =
mode capture.



   =
The knowledgeable experimenter will no doubt notice the similarity =
of



   =
this Ethernet II Header with a capture in normal mode on a =
pure



   =
Ethernet cable interface.



   It =
may be interpreted that an Adaptation layer is inserted in a =
pure



   =
IEEE 802.11 MAC packets in the air, before delivering to =
the



   =
applications.  In detail, this adaptation layer may consist =
in



   =
elimination of the Radiotap, 802.11 and LLC headers and insertion =
of



   =
the Ethernet II header.  In this way, it can be stated that IPv6 =
runs



   =
naturally straight over LLC over the 802.11-OCB MAC layer, as =
shown



   by =
the use of the Type 0x86DD, and assuming an adaptation =
layer



   =
(adapting 802.11 LLC/MAC to Ethernet II header).



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-7.  Security Considerations





   =
Any security mechanism at the IP layer or above that may be =
carried



   =
out for the general case of IPv6 may also be carried out for =
IPv6



   =
operating over 802.11-OCB.



   =
802.11-OCB does not provide any cryptographic protection, because =
it



   =
operates outside the context of a BSS (no Association =
Request/



   =
Response, no Challenge messages).  Any attacker can therefore =
just



   =
sit in the near range of vehicles, sniff the network (just set =
the



   =
interface card's frequency to the proper range) and perform =
attacks



   =
without needing to physically break any wall.  Such a link is =
way



   =
less protected than commonly used links (wired link or =
protected



   =
802.11).



[Sri] Per my =
earlier comment, there is more than one attack vector =
possible



1.) Absence of =
link-layer security and the potential for mac address spoofing =




2.) IP address =
/ Session hijacking 



3.)=A0Data =
privacy per your text





   At =
the IP layer, IPsec can be used to protect unicast =
communications,



   =
and SeND can be used for multicast communications.=A0



[Sri] IPSec can =
be used for protecting both multicast or unicast communication; RFC-5374 =
with GDOI.







 If no =
protection



   is =
used by the IP layer, upper layers should be =
protected.



   =
Otherwise, the end-user or system should be warned about the =
risks



   =
they run.







Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 21]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-22



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   As =
with all Ethernet and 802.11 interface identifiers, there =
may



   =
exist privacy risks in the use of 802.11-OCB interface =
identifiers.



   =
Moreover, in outdoors vehicular settings, the privacy risks are =
more



   =
important than in indoors settings.  New risks are induced by =
the



   =
possibility of attacker sniffers deployed along routes which =
listen



   =
for IP packets of vehicles passing by.  For this reason, in =
the



   =
802.11-OCB deployments, there is a strong necessity to use =
protection



   =
tools such as dynamically changing MAC addresses.  This may =
help



   =
mitigate privacy risks to a certain level.  On another hand, it =
may



   =
have an impact in the way typical IPv6 address auto-configuration =
is



   =
performed for vehicles (SLAAC would rely on MAC addresses amd =
would



   =
hence dynamically change the affected IP address), in the way =
the



   =
IPv6 Privacy addresses were used, and other effects.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-8.  IANA Considerations





https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-802=
11ocb-04#section-9.  Contributors





   =
Romain Kuntz contributed extensively about IPv6 handovers =
between



   =
links running outside the context of a BSS (802.11-OCB =
links).



   =
Tim Leinmueller contributed the idea of the use of IPv6 =
over



   =
802.11-OCB for distribution of certificates.



   =
Marios Makassikis, Jose Santa Lozano, Albin Severinson and =
Alexey



   =
Voronov provided significant feedback on the experience of using =
IP



   =
messages over 802.11-OCB in initial trials.



   =
Michelle Wetterwald contributed extensively the MTU =
discussion,



   =
offered the ETSI ITS perspective, and reviewed other parts of =
the



   =
document.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#section-10.  Acknowledgements





   =
The authors would like to thank Witold Klaudel, Ryuji =
Wakikawa,



   =
Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, =
Dan



   =
Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, =
Ray



   =
Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh =
Krishnan,



   =
Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria =
Gwynne,



   =
Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik =
Nordmark,



   =
Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley =
and



   =
William Whyte.  Their valuable comments clarified certain issues =
and



   =
generally helped to improve the document.



   =
Pierre Pfister, Rostislav Lisovy, and others, wrote =
802.11-OCB



   =
drivers for linux and described how.











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 22]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-23



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
For the multicast discussion, the authors would like to thank =
Owen



   =
DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman =
and



   =
participants to discussions in network working groups.



   =
The authours would like to thank participants to the =
Birds-of-



   =
a-Feather "Intelligent Transportation Systems" meetings held =
at IETF



   in =
2016.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#section-11.  References





https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#section-11.1.  Normative =
References





   =
[I-D.ietf-6man-default-iids]



         &n=
bsp;    Gont, F., Cooper, A., Thaler, D., and S. =
LIU,



         &n=
bsp;    "Recommendation on Stable IPv6 Interface =
Identifiers",



         &n=
bsp;    http=
s://tools.ietf.org/html/draft-ietf-6man-default-iids-16 (work in =
progress),



         &n=
bsp;    September 2016.



   =
[I-D.ietf-6man-ug]



         &n=
bsp;    Carpenter, B. and S. Jiang, "Significance of =
IPv6



         &n=
bsp;    Interface Identifiers", https://tools.=
ietf.org/html/draft-ietf-6man-ug-06 (work in



         &n=
bsp;    progress), December 2013.



   =
[I-D.ietf-tsvwg-ieee-802-11]



         &n=
bsp;    Szigeti, T., Henry, J., and F. Baker, =
"Diffserv to IEEE



         &n=
bsp;    802.11 Mapping", http=
s://tools.ietf.org/html/draft-ietf-tsvwg-ieee-802-11-06 (work =
in



         &n=
bsp;    progress), August 2017.



   =
[RFC1042]  Postel, J. and J. Reynolds, "Standard for the =
transmission



         &n=
bsp;    of IP datagrams over IEEE 802 networks", STD =
43, https://tools.ietf.org/html/=
rfc1042,



         &n=
bsp;    DOI 10.17487/RFC1042, February 1988, =
<https://www.rfc-editor.org/info/rfc1042



         &n=
bsp;    https://www.rfc-editor.o=
rg/info/rfc1042>.



   =
[RFC2119]  Bradner, S., "Key words for use in RFCs to =
Indicate



         &n=
bsp;    Requirement Levels", https://tools.ietf.org/html/bc=
p14, https://tools.ietf.org/html/=
rfc2119,



         &n=
bsp;    DOI 10.17487/RFC2119, March 1997, =
<https://www.rfc-editor.org/info/rfc2119



         &n=
bsp;    https://www.rfc-editor.o=
rg/info/rfc2119>.



   =
[RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, =
Version 6



         &n=
bsp;    (IPv6) Specification", https://tools.ietf.org/html/=
rfc2460, DOI 10.17487/RFC2460,



         &n=
bsp;    December 1998, <https://www.rfc-editor.o=
rg/info/rfc2460>.



   =
[RFC2464]  Crawford, M., "Transmission of IPv6 Packets over =
Ethernet



         &n=
bsp;    Networks", https://tools.ietf.org/html/=
rfc2464, DOI 10.17487/RFC2464, December 1998,



         &n=
bsp;    <https://www.rfc-editor.o=
rg/info/rfc2464>.













Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 23]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-24



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
[RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and =
P.



         &n=
bsp;    Thubert, "Network Mobility (NEMO) Basic =
Support Protocol",



         &n=
bsp;    https://tools.ietf.org/html/=
rfc3963, DOI 10.17487/RFC3963, January 2005,



         &n=
bsp;    <https://www.rfc-editor.o=
rg/info/rfc3963>.



   =
[RFC4086]  Eastlake 3rd, D., Schiller, J., and S. =
Crocker,



         &n=
bsp;    "Randomness Requirements for Security", =
https://tools.ietf.org/html/b=
cp106, https://tools.ietf.org/html/=
rfc4086,



         &n=
bsp;    DOI 10.17487/RFC4086, June 2005, =
<https://www.rfc-editor.org/info/rfc4086



         &n=
bsp;    https://www.rfc-editor.o=
rg/info/rfc4086>.



   [RFC4301]  Kent, S. and K. Seo, "Security =
Architecture for the



         &n=
bsp;    Internet Protocol", https://tools.ietf.org/html/=
rfc4301, DOI 10.17487/RFC4301,



         &n=
bsp;    December 2005, <https://www.rfc-editor.o=
rg/info/rfc4301>.



   =
[RFC4429]  Moore, N., "Optimistic Duplicate Address Detection =
(DAD)



         &n=
bsp;    for IPv6", https://tools.ietf.org/html/=
rfc4429, DOI 10.17487/RFC4429, April 2006,



         &n=
bsp;    <https://www.rfc-editor.o=
rg/info/rfc4429>.



   =
[RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. =
Soliman,



         &n=
bsp;    "Neighbor Discovery for IP version 6 =
(IPv6)", https://tools.ietf.org/html/=
rfc4861,



         &n=
bsp;    DOI 10.17487/RFC4861, September 2007, =
<https://www.rfc-editor.org/info/rfc4861



         &n=
bsp;    https://www.rfc-editor.o=
rg/info/rfc4861>.



   =
[RFC5889]  Baccelli, E., Ed. and M. Townsley, Ed., "IP =
Addressing



         &n=
bsp;    Model in Ad Hoc Networks", https://tools.ietf.org/html/=
rfc5889, DOI 10.17487/RFC5889,



         &n=
bsp;    September 2010, <https://www.rfc-editor.o=
rg/info/rfc5889>.



   =
[RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, =
"Mobility



         &n=
bsp;    Support in IPv6", https://tools.ietf.org/html/=
rfc6275, DOI 10.17487/RFC6275, July



         &n=
bsp;    2011, <https://www.rfc-editor.o=
rg/info/rfc6275>.



   =
[RFC6775]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and =
C.



         &n=
bsp;    Bormann, "Neighbor Discovery Optimization =
for IPv6 over



         &n=
bsp;    Low-Power Wireless Personal Area Networks =
(6LoWPANs)",



         &n=
bsp;    https://tools.ietf.org/html/=
rfc6775, DOI 10.17487/RFC6775, November 2012,



         &n=
bsp;    <https://www.rfc-editor.o=
rg/info/rfc6775>.



   =
[RFC7721]  Cooper, A., Gont, F., and D. Thaler, "Security and =
Privacy



         &n=
bsp;    Considerations for IPv6 Address Generation =
Mechanisms",



         &n=
bsp;    https://tools.ietf.org/html/=
rfc7721, DOI 10.17487/RFC7721, March 2016,



         &n=
bsp;    <https://www.rfc-editor.o=
rg/info/rfc7721>.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#section-11.2.  Informative =
References



















Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 24]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-25



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
[fcc-cc]   "'Report and Order, Before the Federal =
Communications



         &n=
bsp;    Commission Washington, D.C. 20554', FCC 03-324, =
Released



         &n=
bsp;    on February 10, 2004, document FCC-03-324A1.pdf, =
document



         &n=
bsp;    freely available at URL



         &n=
bsp;    http://www.its.dot.gov=
/exit/fcc_edocs.htm downloaded on



         &n=
bsp;    October 17th, 2013.".



   =
[fcc-cc-172-184]



         &n=
bsp;    "'Memorandum Opinion and Order, Before the =
Federal



         &n=
bsp;    Communications Commission Washington, D.C. =
20554', FCC



         &n=
bsp;    06-10, Released on July 26, 2006, document =
FCC-



         &n=
bsp;    06-110A1.pdf, document freely available at =
URL



         &n=
bsp;    http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A1.pdf=




         &n=
bsp;    http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A1.pdf=
 downloaded on June 5th, 2014.".



   =
[I-D.jeong-ipwave-vehicular-networking-survey]



         &n=
bsp;    Jeong, J., Cespedes, S., Benamar, N., Haerri, J., =
and M.



         &n=
bsp;    Wetterwald, "Survey on IP-based Vehicular =
Networking for



         &n=
bsp;    Intelligent Transportation Systems", https://tools.ietf.org/html/draft-jeong-ipwave-vehicular-ne=
tworking-survey-03



         &n=
bsp;    https://tools.ietf.org/html/draft-jeong-ipwave-vehicular-ne=
tworking-survey-03 (work in progress), June



         &n=
bsp;    2017.



   =
[I-D.perkins-intarea-multicast-ieee802]



         &n=
bsp;    Perkins, C., Stanley, D., Kumari, W., and J. =
Zuniga,



         &n=
bsp;    "Multicast Considerations over IEEE 802 =
Wireless Media",



         &n=
bsp;    https://tools.ietf.org/html/draft-perkins-intarea-multicast-ieee80=
2-03 (work in



         &n=
bsp;    progress), July 2017.



   =
[I-D.petrescu-its-scenarios-reqs]



         &n=
bsp;    Petrescu, A., Janneteau, C., Boc, M., and W. =
Klaudel,



         &n=
bsp;    "Scenarios and Requirements for IP in =
Intelligent



         &n=
bsp;    Transportation Systems", https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs-03



         &n=
bsp;    https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs-03 =
(work in progress), October 2013.



   =
[ieee1609.2]



         &n=
bsp;    "IEEE SA - 1609.2-2016 - IEEE Standard for =
Wireless Access



         &n=
bsp;    in Vehicular Environments (WAVE) -- Security =
Services for



         &n=
bsp;    Applications and Management Messages.  =
Example URL



         &n=
bsp;    http://ieeexplore.i=
eee.org/document/7426684/ accessed on



         &n=
bsp;    August 17th, 2017.".



   =
[ieee1609.3]



         &n=
bsp;    "IEEE SA - 1609.3-2016 - IEEE Standard for =
Wireless Access



         &n=
bsp;    in Vehicular Environments (WAVE) -- Networking =
Services.



         &n=
bsp;    Example URL http://ieee=
xplore.ieee.org/document/7458115/accessed



         &n=
bsp;    http://ieee=
xplore.ieee.org/document/7458115/accessed on August 17th, =
2017.".











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 25]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-26



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
[ieee1609.4]



         &n=
bsp;    "IEEE SA - 1609.4-2016 - IEEE Standard for =
Wireless Access



         &n=
bsp;    in Vehicular Environments (WAVE) -- =
Multi-Channel



         &n=
bsp;    Operation.  Example URL



         &n=
bsp;    http://ieeexplore.i=
eee.org/document/7435228/ accessed on



         &n=
bsp;    August 17th, 2017.".



   =
[ieee802.11-2012]



         &n=
bsp;    "802.11-2012 - IEEE Standard for Information =
technology--



         &n=
bsp;    Telecommunications and information exchange =
between



         &n=
bsp;    systems Local and metropolitan area =
networks--Specific



         &n=
bsp;    requirements Part 11: Wireless LAN Medium Access =
Control



         &n=
bsp;    (MAC) and Physical Layer (PHY) =
Specifications.  Downloaded



         &n=
bsp;    on October 17th, 2013, from IEEE Standards, =
document



         &n=
bsp;    freely available at URL



         &n=
bsp;    htt=
p://standards.ieee.org/findstds/standard/802.11-2012.html



         &n=
bsp;    htt=
p://standards.ieee.org/findstds/standard/802.11-2012.html retrieved =
on October 17th,



         &n=
bsp;    2013.".



   =
[ieee802.11p-2010]



         &n=
bsp;    "IEEE Std 802.11p (TM)-2010, IEEE Standard =
for Information



         &n=
bsp;    Technology - Telecommunications and information =
exchange



         &n=
bsp;    between systems - Local and metropolitan area =
networks -



         &n=
bsp;    Specific requirements, Part 11: Wireless LAN =
Medium Access



         &n=
bsp;    Control (MAC) and Physical Layer (PHY) =
Specifications,



         &n=
bsp;    Amendment 6: Wireless Access in Vehicular =
Environments;



         &n=
bsp;    document freely available at =
URL



         &n=
bsp;    h=
ttp://standards.ieee.org/getieee802/download/802.11p-2010.pdf<=
/SPAN>



         &n=
bsp;    h=
ttp://standards.ieee.org/getieee802/download/802.11p-2010.pdf =
retrieved on September 20th,



         &n=
bsp;    2013.".



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-A.  ChangeLog





   =
The changes are listed in reverse chronological order, most =
recent



   =
changes appearing at the top of the list.



   =
>From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04



   =
o  Removed a few informative references pointing to Dx draft =
IEEE



      1609 =
documents.



   =
o  Removed outdated informative references to ETSI =
documents.



   =
o  Added citations to IEEE 1609.2, .3 and =
.4-2016.



   =
o  Minor textual issues.









Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 26]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-27



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
>From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03



   =
o  Keep the previous text on multiple addresses, so remove talk =
about



      MIP6, NEMOv6 and =
MCoA.



   =
o  Clarified that a 'Beacon' is an IEEE 802.11 frame =
Beacon.



   =
o  Clarified the figure showing Infrastructure mode and OCB mode =
side



      by =
side.



   =
o  Added a reference to the IP Security Architecture =
RFC.



   =
o  Detailed the IPv6-per-channel prohibition paragraph which =
reflects



      the discussion at the =
last IETF IPWAVE WG meeting.



   =
o  Added section "Address Mapping -- =
Unicast".



   =
o  Added the ".11 Trailer" to pictures of 802.11 =
frames.



   =
o  Added text about SNAP carrying the Ethertype.



   =
o  New RSU definition allowing for it be both a Router and =
not



      necessarily a Router =
some times.



   =
o  Minor textual issues.



   =
>From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02



   =
o  Replaced almost all occurences of 802.11p with 802.11-OCB, =
leaving



      only when explanation of =
evolution was necessary.



   =
o  Shortened by removing parameter details from a paragraph in =
the



      =
Introduction.



   =
o  Moved a reference from Normative to =
Informative.



   =
o  Added text in intro clarifying there is no handover spec at =
IEEE,



      and that 1609.2 does =
provide security services.



   =
o  Named the contents the fields of the EthernetII header =
(including



      the Ethertype =
bitstring).



   =
o  Improved relationship between two paragraphs describing =
the



      increase of the Sequence =
Number in 802.11 header upon IP



      fragmentation.









Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 27]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-28



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
o  Added brief clarification of =
"tracking".



   =
>From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-00 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01



   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01



   =
o  Introduced message exchange diagram illustrating =
differences



      between 802.11 and =
802.11 in OCB mode.



   =
o  Introduced an appendix listing for information the set of =
802.11



      messages that may be =
transmitted in OCB mode.



   =
o  Removed appendix sections "Privacy Requirements", =
"Authentication



      Requirements" and =
"Security Certificate Generation".



   =
o  Removed appendix section "Non IP =
Communications".



   =
o  Introductory phrase in the Security Considerations =
section.



   =
o  Improved the definition of "OCB".



   =
o  Introduced theoretical stacked layers about IPv6 and IEEE =
layers



      including =
EPD.



   =
o  Removed the appendix describing the details of prohibiting IPv6 =
on



      certain channels =
relevant to 802.11-OCB.



   =
o  Added a brief reference in the privacy text about a precise =
clause



      in IEEE 1609.3 and =
.4.



   =
o  Clarified the definition of a Road Side Unit.



   =
o  Removed the discussion about security of WSA (because is =
non-IP).



   =
o  Removed mentioning of the GeoNetworking =
discussion.



   =
o  Moved references to scientific articles to a separate =
'overview'



      draft, and referred to =
it.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-B.  Changes Needed on a software driver =
802.11a to become a



         &n=
bsp;   802.11-OCB driver



   =
The 802.11p amendment modifies both the 802.11 stack's physical =
and



   =
MAC layers but all the induced modifications can be quite =
easily



   =
obtained by modifying an existing 802.11a ad-hoc =
stack.



   =
Conditions for a 802.11a hardware to be 802.11-OCB =
compliant:











Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 28]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-29



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
o  The chip must support the frequency bands on which the =
regulator



      recommends the use of =
ITS communications, for example using IEEE



      802.11-OCB layer, in =
France: 5875MHz to 5925MHz.



   =
o  The chip must support the half-rate mode (the internal =
clock



      should be able to be =
divided by two).



   =
o  The chip transmit spectrum mask must be compliant to the =
"Transmit



      spectrum mask" from =
the IEEE 802.11p amendment (but experimental



      environments tolerate =
otherwise).



   =
o  The chip should be able to transmit up to 44.8 dBm when used =
by



      the US government in the =
United States, and up to 33 dBm in



      Europe; other regional =
conditions apply.



   =
Changes needed on the network stack in OCB mode:



   =
o  Physical layer:



      *  The chip must =
use the Orthogonal Frequency Multiple Access



         (OFDM) =
encoding mode.



      *  The chip must be =
set in half-mode rate mode (the internal clock



         =
frequency is divided by two).



      *  The chip must =
use dedicated channels and should allow the use



         of =
higher emission powers.  This may require modifications =
to



         the =
regulatory domains rules, if used by the kernel to =
enforce



         local =
specific restrictions.  Such modifications must =
respect



         the =
location-specific laws.



      MAC =
layer:



      *  All management =
frames (beacons, join, leave, and others)



         =
emission and reception must be disabled except for frames =
of



         =
subtype Action and Timing Advertisement (defined =
below).



      *  No encryption =
key or method must be used.



      *  Packet emission =
and reception must be performed as in ad-hoc



         mode, =
using the wildcard BSSID (ff:ff:ff:ff:ff:ff).



      *  The functions =
related to joining a BSS (Association Request/



         =
Response) and for authentication (Authentication =
Request/Reply,



         =
Challenge) are not called.



      *  The beacon =
interval is always set to 0 (zero).









Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 29]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-30



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





      *  Timing =
Advertisement frames, defined in the amendment, should



         be =
supported.  The upper layer should be able to trigger =
such



         frames =
emission and to retrieve information contained in



         =
received Timing Advertisements.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-C.  Design Considerations





   =
The networks defined by 802.11-OCB are in many ways similar to =
other



   =
networks of the 802.11 family.  In theory, the encapsulation of =
IPv6



   =
over 802.11-OCB could be very similar to the operation of IPv6 =
over



   =
other networks of the 802.11 family.  However, the high =
mobility,



   =
strong link asymetry and very short connection makes the =
802.11-OCB



   =
link significantly different from other 802.11 networks.  Also, =
the



   =
automotive applications have specific requirements for =
reliability,



   =
security and privacy, which further add to the particularity of =
the



   =
802.11-OCB link.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#appendix-C.1.  Vehicle ID





   =
Automotive networks require the unique representation of each =
of



   =
their node.  Accordingly, a vehicle must be identified by at =
least



   =
one unique identifier.  The current specification at ETSI and at =
IEEE



   =
1609 identifies a vehicle by its MAC address uniquely obtained =
from



   =
the 802.11-OCB NIC.



   A =
MAC address uniquely obtained from a IEEE 802.11-OCB =
NIC



   =
implicitely generates multiple vehicle IDs in case of =
multiple



   =
802.11-OCB NICs.  A mechanims to uniquely identify a =
vehicle



   =
irrespectively to the different NICs and/or technologies is =
required.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#appendix-C.2.  Reliability =
Requirements





   =
The dynamically changing topology, short connectivity, =
mobile



   =
transmitter and receivers, different antenna heights, and =
many-to-



   =
many communication types, make IEEE 802.11-OCB links =
significantly



   =
different from other IEEE 802.11 links.  Any IPv6 mechanism =
operating



   on =
IEEE 802.11-OCB link MUST support strong link asymetry, =
spatio-



   =
temporal link quality, fast address resolution and =
transmission.



   =
IEEE 802.11-OCB strongly differs from other 802.11 systems to =
operate



   =
outside of the context of a Basic Service Set.  This means =
in



   =
practice that IEEE 802.11-OCB does not rely on a Base Station for =
all



   =
Basic Service Set management.  In particular, IEEE 802.11-OCB =
SHALL



   =
NOT use beacons.  Any IPv6 mechanism requiring L2 services from =
IEEE



   =
802.11 beacons MUST support an alternative service.













Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 30]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-31



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
Channel scanning being disabled, IPv6 over IEEE 802.11-OCB =
MUST



   =
implement a mechanism for transmitter and receiver to converge to =
a



   =
common channel.



   =
Authentication not being possible, IPv6 over IEEE 802.11-OCB =
MUST



   =
implement an distributed mechanism to authenticate transmitters =
and



   =
receivers without the support of a DHCP server.



   =
Time synchronization not being available, IPv6 over IEEE =
802.11-OCB



   =
MUST implement a higher layer mechanism for time =
synchronization



   =
between transmitters and receivers without the support of a =
NTP



   =
server.



   =
The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE =
802.11-OCB



   =
MUST disable management mechanisms requesting acknowledgements =
or



   =
replies.



   =
The IEEE 802.11-OCB link having a short duration time, IPv6 over =
IEEE



   =
802.11-OCB MUST implement fast IPv6 mobility management =
mechanisms.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#appendix-C.3.  Multiple =
interfaces





   =
There are considerations for 2 or more IEEE 802.11-OCB =
interface



   =
cards per vehicle.  For each vehicle taking part in road traffic, =
one



   =
IEEE 802.11-OCB interface card could be fully allocated for Non =
IP



   =
safety-critical communication.  Any other IEEE 802.11-OCB may be =
used



   =
for other type of traffic.



   =
The mode of operation of these other wireless interfaces is =
not



   =
clearly defined yet.  One possibility is to consider each card as =
an



   =
independent network interface, with a specific MAC Address and a =
set



   of =
IPv6 addresses.  Another possibility is to consider the set =
of



   =
these wireless interfaces as a single network interface =
(not



   =
including the IEEE 802.11-OCB interface used by Non IP =
safety



   =
critical communications).  This will require specific logic =
to



   =
ensure, for example, that packets meant for a vehicle in front =
are



   =
actually sent by the radio in the front, or that multiple copies =
of



   =
the same packet received by multiple interfaces are treated as =
a



   =
single packet.  Treating each wireless interface as a =
separate



   =
network interface pushes such issues to the application =
layer.



   =
The privacy requirements of [] imply that if these =
multiple



   =
interfaces are represented by many network interface, a =
single



   =
renumbering event SHALL cause renumbering of all these =
interfaces.



   If =
one MAC changed and another stayed constant, external =
observers



   =
would be able to correlate old and new values, and the =
privacy



   =
benefits of randomization would be lost.









Petrescu, et =
al.        Expires February 18, =
2018           &nb=
sp;  [Page 31]



________________________________________


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#page-32



Internet-Draft       =
      =
IPv6-over-80211ocb         &=
nbsp;      August 2017





   =
The privacy requirements of Non IP safety-critical =
communications



   =
imply that if a change of pseudonyme occurs, renumbering of all =
other



   =
interfaces SHALL also occur.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#appendix-C.4.  MAC Address =
Generation





   =
When designing the IPv6 over 802.11-OCB address mapping, we =
will



   =
assume that the MAC Addresses will change during well =
defined



   =
"renumbering events".  The 48 bits randomized MAC =
addresses will have



   =
the following characteristics:



   =
o  Bit "Local/Global" set to "locally =
admninistered".



   =
o  Bit "Unicast/Multicast" set to =
"Unicast".



   =
o  46 remaining bits set to a random value, using a random =
number



      generator that meets the =
requirements of [https://tools.ietf.org/html/=
rfc4086].



   =
The way to meet the randomization requirements is to retain 46 =
bits



   =
from the output of a strong hash function, such as SHA256, taking =
as



   =
input a 256 bit local secret, the "nominal" MAC Address of =
the



   =
interface, and a representation of the date and time of =
the



   =
renumbering event.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80=
211ocb-04#appendix-D.  IEEE 802.11 Messages Transmitted in OCB =
mode





   =
For information, at the time of writing, this is the list of =
IEEE



   =
802.11 messages that may be transmitted in OCB mode, i.e. =
when



   =
dot11OCBActivated is true in a STA:



   =
o  The STA may send management frames of subtype Action and, if =
the



      STA maintains a TSF =
Timer, subtype Timing Advertisement;



   =
o  The STA may send control frames, except those of subtype =
PS-Poll,



      CF-End, and CF-End plus =
CFAck;



   =
o  The STA may send data frames of subtype Data, Null, QoS Data, =
and



      QoS =
Null.



Authors' =
Addresses







------=_NextPart_000_0075_01D32007.19622A40--


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From: "Sri Gundavelli (sgundave)" 
To: =?Windows-1252?Q?Fran=E7ois_Simon?= 
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Hi Francois,

Thanks you for your response and also for clarification on the QoS aspects =
which are present in OCB. Hopefully, you can address these comments and my =
other comments in the next rev.




Regards
Sri



From: Fran=E7ois Simon >
Date: Monday, August 28, 2017 at 11:08 AM
To: Sri Gundavelli >
Cc: "its@ietf.org" >=
, "fygsimon@gmail.com" >
Subject: RE: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211o=
cb-04.txt


Mr. Gundaveli,

I provided some comments and responses in the text below your comments iden=
tified by=93[Fygs] and =93bold=94.

If you have additional questions, please, let me know.

Sincerely,

Francois Simon

From: its [mailto:its-bounces@ietf.org] On Behalf Of Sri Gundavelli (sgunda=
ve)

Sent: Sunday, August 27, 2017 11:01 PM

To: its@ietf.org

Subject: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-0=
4.txt


Attached is my review feedback.

In general there is lot of good information in the document. But, there are=
 also few areas where additional clarifications will greatly help.

1.) Its not clear, if the document makes any assumption on the operating en=
vironment/communication profile. There is not much discussion on that aspec=
t; For example, Is it always a one-hop communication between RSU and OBU wh=
ere the 802.11-OCB link?  So, is the use of IPv6 only in that context of 1-=
hop communication?

2.) There is also no discussion on how these links get formed in vehicular =
environment and when they are attached/detached.

3.) How do nodes discover each other?  How does ND resolution work? Are the=
se messages received by a multiple RSU=92s, or a single RSU? Whats the impl=
ication of that. Note that you don=92t have that issue in 802.11, given the=
 association to an access point, which in turn maps the links to a VLAN/sub=
net.

4.) What happens as a vehicle moves between RSU=92s, how does it impact add=
ress configuration?   Is DHCPv6 based address configuration relevant here?


 Please see inline for additional comments.



------------------------------------------------------------------



Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside



the Context of a Basic Service Set (IPv6-over-80211ocb)



draft-ietf-ipwave-ipv6-over-80211ocb-04.txt



[Sri] May be change to, =93..in mode .." =97> =93..operating in mode ..=94 =
 ?

[Fygs] Agreed


Abstract

   In order to transmit IPv6 packets on IEEE 802.11 networks run outside

   the context of a basic service set (OCB, earlier "802.11p") there is

   a need to define a few parameters such as the recommended Maximum

   Transmission Unit size, the header format preceding the IPv6 header,

   the Type value within it, and others.  This document describes these

   parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the

   layering of IPv6 on 802.11 OCB similarly to other known 802.11 and

   Ethernet layers - by using an Ethernet Adaptation Layer.

[Sri] Is it =93recommended MTU size", or "supported MTU size on the 802.11 =
OCB link?


   In addition, the document attempts to list what is different in

   802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n

   layers, layers over which IPv6 protocols operates without issues.

   Most notably, the operation outside the context of a BSS (OCB) has

   impact on IPv6 handover behaviour and on IPv6 security.

[Sri] Minor comment. May be instead of using the =93layer=94 terminology, y=
ou may want to present this as IPv6 support on "802.11 OCB" links.

[Fygs] 802.11 OCB provides data link and PHY services to IPv6



   An example of an IPv6 packet captured while transmitted over an IEEE

   802.11 OCB link (802.11p) is given.

[Sri] Last paragraph can be ommitted in my view. That=92s too much of detai=
l for Abstract.

[Fygs] - Agree

Status of This Memo

   This Internet-Draft is submitted in full conformance with the

   provisions of https://tools.ietf.org/html/bcp78 and https://tools.ietf.o=
rg/html/bcp79.

   Internet-Drafts are working documents of the Internet Engineering

   Task Force (IETF).  Note that other groups may also distribute



Petrescu, et al.        Expires February 18, 2018               [Page 1]

________________________________________

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-2

Internet-Draft             IPv6-over-80211ocb                August 2017


   working documents as Internet-Drafts.  The list of current Internet-

   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months

   and may be updated, replaced, or obsoleted by other documents at any

   time.  It is inappropriate to use Internet-Drafts as reference

   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 18, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the

   document authors.  All rights reserved.

   This document is subject to https://tools.ietf.org/html/bcp78 and the IE=
TF Trust's Legal

   Provisions Relating to IETF Documents

   (http://trustee.ietf.org/license-info) in effect on the date of

   publication of this document.  Please review these documents

   carefully, as they describe your rights and restrictions with respect

   to this document.  Code Components extracted from this document must

   include Simplified BSD License text as described in Section 4.e of

   the Trust Legal Provisions and are provided without warranty as

   described in the Simplified BSD License.

Table of Contents

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-3

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-5

   3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    6

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-4.  Aspects introduced by the OCB mode to 802.11  . . . . . . . .   htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-6

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-5.  Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-10

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-5.1.  Maximum Transmission Unit (MTU) . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-10

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-5.2. Frame Format  . . . . . . . . . . . . . . . . . . . . . .  https=
://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-11

       https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#=
section-5.2.1.  Ethernet Adaptation Layer . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-12

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-5.3. Link-Local Addresses  . . . . . . . . . . . . . . . . . .  https=
://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-13

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-5.4.  Address Mapping . . . . . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14

       https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#=
section-5.4.1.  Address Mapping -- Unicast  . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14

       https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#=
section-5.4.2.  Address Mapping -- Multicast  . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-5.5.  Stateless Autoconfiguration . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-15

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-5.6. Subnet Structure  . . . . . . . . . . . . . . . . . . . .  https=
://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-16

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-6. Example IPv6 Packet captured over a IEEE 802.11-OCB link  . .  https=
://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-16

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-6.1.  Capture in Monitor Mode . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-17

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-6.2.  Capture in Normal Mode  . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-19

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-7.  Security Considerations . . . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-21

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22



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   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-23

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-11.1.  Normative References . . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-23

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#se=
ction-11.2.  Informative References . . . . . . . . . . . . . . . . .  http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-24

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appe=
ndix-A.  ChangeLog  . . . . . . . . . . . . . . . . . . . . .  https://tool=
s.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-26

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appe=
ndix-B.  Changes Needed on a software driver 802.11a to

                become a                     802.11-OCB driver . . .  https=
://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-28

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appe=
ndix-C.  Design Considerations  . . . . . . . . . . . . . . .  https://tool=
s.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ap=
pendix-C.1.  Vehicle ID  . . . . . . . . . . . . . . . . . . . . . . .  htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ap=
pendix-C.2.  Reliability Requirements  . . . . . . . . . . . . . . . .  htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ap=
pendix-C.3.  Multiple interfaces . . . . . . . . . . . . . . . . . . .  htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-31

     https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ap=
pendix-C.4.  MAC Address Generation  . . . . . . . . . . . . . . . . .  htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appe=
ndix-D.  IEEE 802.11 Messages Transmitted in OCB mode . . . .  https://tool=
s.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32

   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  https=
://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-1.  Introduction


   This document describes the transmission of IPv6 packets on IEEE Std

   802.11 OCB networks (earlier known as 802.11p).

[Sri] Please add a reference to the IEEE specification that defines the OCB=
 mode.

[Fygs] Since 2010 the OCB is defined in IEEE Std 802.11p, IEEE Std 802.11-2=
012, and IEEE 802.11-2016.

This involves the

   layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with

   an LLC layer).  Compared to running IPv6 over the Ethernet MAC layer,

   there is no modification required to the standards: IPv6 works fine

   directly over 802.11 OCB too (with an LLC layer).

   The term "802.11p" is an earlier definition.  As of year 2012, the

   behaviour of "802.11p" networks has been rolled in the document IEEE

   Std 802.11-2012.  In this document the term 802.11p disappears.

   Instead, each 802.11p feature is conditioned by a flag in the

   Management Information Base.  That flag is named "OCBActivated".

   Whenever OCBActivated is set to true the feature it relates to

   represents an earlier 802.11p feature.  For example, an 802.11

   STAtion operating outside the context of a basic service set has the

   OCBActivated flag set.  Such a station, when it has the flag set, it

   uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.

   In the following text we use the term "802.11p" to mean 802.11-2012

   OCB.

   The IPv6 network layer operates on 802.11 OCB in the same manner as

   it operates on 802.11 WiFi, with a few particular exceptions.  The

   IPv6 network layer operates on WiFi by involving an Ethernet

   Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers

   to Ethernet II headers.  The operation of IP on Ethernet is described

   in [https://tools.ietf.org/html/rfc1042] and [https://tools.ietf.org/htm=
l/rfc2464].  The situation of IPv6 networking layer

   on Ethernet Adaptation Layer is illustrated below:







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                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 |                 IPv6                  |

                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 |       Ethernet Adaptation Layer       |

                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 |             802.11 WiFi MAC           |

                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 |             802.11 WiFi PHY           |

                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   (in the above figure, a WiFi profile is represented; this is used

   also for OCB profile.)

   A more theoretical and detailed view of layer stacking, and

   interfaces between the IP layer and 802.11 OCB layers, is illustrated

   below.  The IP layer operates on top of the EtherType Protocol

   Discrimination (EPD); this Discrimination layer is described in IEEE

   Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP

   (Link Layer Control Service Accesss Point).


           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

           |                 IPv6                  |

           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+

                       {   LLC_SAP  }                 802.11 OCB

           +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+  Boundary

           |            EPD          |       |     |

           |                         | MLME  |     |

           +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   |

           |      MAC Sublayer       |       |     |  802.11 OCB

           |     and ch. coord.      |       | SME |  Services

           +-+-+-{   PHY_SAP  }+-+-+-+-+-+-+-|     |

           |                         | PLME  |     |

           |            PHY Layer    |   PLME_SAP  |

           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   In addition to the description of interface between IP and MAC using

   "Ethernet Adaptation Layer" and "Ethernet Protocol Discrimination

   (EPD)" it is worth mentioning that SNAP [https://tools.ietf.org/html/rfc=
1042] is used to carry

   the IPv6 Ethertype.

   However, there may be some deployment considerations helping optimize

   the performances of running IPv6 over 802.11-OCB (e.g. in the case of

   handovers between 802.11 OCB-enabled access routers, or the

   consideration of using the IP security layer [https://tools.ietf.org/htm=
l/rfc4301]).




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   There are currently no specifications for handover between OCB links

   since these are currently specified as LLC-1 links (i.e.

   connectionless).  Any handovers must be performed above the Data Link

   Layer.  Also, while there is no encryption applied below the network

   layer using 802.11p, 1609.2 [https://tools.ietf.org/html/draft-ietf-ipwa=
ve-ipv6-over-80211ocb-04#ref-ieee1609.2] does provide security

   services for applications to use so that there can easily be data

   security over the air without invoking IPsec.

   We briefly introduce the vehicular communication scenarios where IEEE

   802.11-OCB links are used.

[Sri] I have not seen much discussion on the link / communication assumptio=
ns.

[Fygs] Not sure of what is meant by assumptions in this context.

 This is followed by a description of

   differences in specification terms, between 802.11 OCB and

   802.11a/b/g/n (and the same differences expressed in terms of

   requirements to software implementation are listed in https://tools.ietf=
.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-B.)

   The document then concentrates on the parameters of layering IP over

   802.11 OCB as over Ethernet: value of MTU, the contents of Frame

   Format, the rules for forming Interface Identifiers, the mechanism

   for Address Mapping and for State-less Address Auto-configuration.

   These are precisely the same as IPv6 over Ethernet [https://tools.ietf.o=
rg/html/rfc2464].

   As an example, these characteristics of layering IPv6 straight over

   LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet

   captured over a 802.11 OCB link; this is described in the section

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-6.

   A couple of points can be considered as different, although they are

   not required in order to have a working implementation of IPv6-over-

   802.11-OCB.  These points are consequences of the OCB operation which

   is particular to 802.11 OCB (Outside the Context of a BSS).  First,

   the handovers between OCB links need specific behaviour for IP Router

   Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of

   higher layer messages such as the 'Basic Safety Message' (in the US)

   or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE

   Routing Advertisement'; second, the IP security mechanisms are

   necessary, since OCB means that 802.11 is stripped of all 802.11

   link-layer security; a small additional security aspect which is

   shared between 802.11 OCB and other 802.11 links is the privacy

   concerns related to the address formation mechanisms.

   In the published literature, many documents describe aspects related

   to running IPv6 over 802.11 OCB:

   [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref=
-I-D.jeong-ipwave-vehicular-networking-survey].

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-2.  Terminology


   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",

   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this

   document are to be interpreted as described in https://tools.ietf.org/ht=
ml/rfc2119 [https://tools.ietf.org/html/rfc2119].



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   RSU: Road Side Unit.  A computer equipped with at least one IEEE

   802.11 interface operated in OCB mode.  This definition applies to

   this document.  An RSU may be connected to the Internet, and may be

   equipped with additional wired or wireless network interfaces running

   IP.  An RSU MAY be an IP Router.


[Sri] RSU can be compared to an 802.11 access point; Or, WTP as defined in =
CAPWAP specification, RFC5415.

[Fygs] While I am not familiar with =93WTP as defined in CAPWAP specificati=
on, RFC5415=94, I know that an RSU has no commonality with an 802.11 AP.

Perhaps. rephrase as below?:

"RSU: Road Side Unit. Its a wireless termination point (WTP), as defined in=
 RFC5415 with one key difference, where the wireless physical and the mac l=
ayer is MAC layers configured to operate in 802.11 OCB mode.  The RSU commu=
nicates with the On board Unit (OBU) in the vehicle over 802.11 wireless li=
nk operating in OCB mode.=94

[Fygs]:  This seems reasonable and accurate.  This would be for V2I mode.

** Also, since you are defining the RSU term, should you also not define OB=
U (On board Unit) in the vehicle which is the entity on the other end of th=
e link? =93RSU ----802.11-OCB=97=97OBU=94 ? May be introduce the OCB defini=
tion separately, just as you did with RSU, and show the communication link =
as 802.11-OCB.

[Fygs] Here is a definition of OBU (FCC): =93An On-Board Unit is a DSRCS tr=
ansceiver that is normally mounted in or on a vehicle, or which in some ins=
tances may be a portable unit. An OBU can be operational while a vehicle or=
 person is either mobile or stationary.=94

   OCB: outside the context of a basic service set (BSS): A mode of

   operation in which a STA is not a member of a BSS and does not

   utilize IEEE Std 802.11 authentication, association, or data

   confidentiality.

   802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is

   flagged by "dot11OCBActivated".  This means: IEEE 802.11e for quality

   of service; 802.11j-2004 for half-clocked operations; and (what was

   known earlier as) 802.11p for operation in the 5.9 GHz band and in

   mode OCB.


[Sri] The text starting with. =93This means=94 is not clear to me. Does it =
802.11e is supported with 802.11OCB mode. Please clarify

[Fygs]QoS is required for 802.11 OCB.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-3.  Communication Scenarios where IEEE 802.11 OCB Links are Used


   The IEEE 802.11 OCB Networks are used for vehicular communications,

   as 'Wireless Access in Vehicular Environments'.  The IP communication

   scenarios for these environments have been described in several

   documents, among which we refer the reader to one recently updated

   [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref=
-I-D.petrescu-its-scenarios-reqs], about scenarios and requirements

   for IP in Intelligent Transportation Systems.


[Sri] You can do bit more justice to this section.

Explain the link model.  =93STA ----802.11-OCB=97=97STA=94. Then talk about=
 the applicability in Vehicular networks, with STA's as RSU and OCB.

You may also want to talk about, how links get formed/terminated; how nodes=
 peer/discover and how mobility works ..etc.  While 802.11-OCB is clearly s=
pecified and the use of IPv6 over such link is also not radically new, but =
the operating environment which is vehicular brings many new things. That d=
escription is not present any where.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-4.  Aspects introduced by the OCB mode to 802.11


   In the IEEE 802.11 OCB mode, all nodes in the wireless range can

   directly communicate with each other without authentication/

   association procedures.  Briefly, the IEEE 802.11 OCB mode has the

   following properties:


[Sri] Can you add some text on how nodes (ST1 and STA2) discover each other=
 on such links supporting 802.11 OCB mode.

   o  The use by each node of a 'wildcard' BSSID (i.e., each bit of the

      BSSID is set to 1)

   o  No IEEE 802.11 Beacon frames transmitted

   o  No authentication required

   o  No association needed

o      No encryption provided

[Fygs] All the nodes in the communication range (OBU and RSU) receivesall t=
he messages transmitted (OBU and RSU) within the communications range. The =
conflicts are resolved by the MAC CDMA function.

[Sri] Can you clarify what you mean when you say =93No xxx required=94 / =
=93No xxx needed=94  for the above capabilities.  What does =93needed=94 or=
 =93required=94 mean?  Does it mean, =93Authentication", =93Association" an=
d =93Encryption=94 is optional on this link, or that its not supported on 8=
02.11 OCB links.

[Fygs]The original text in IEEE 802.11p specifies:

=93Change the lettered list items (a) through (c) of 5.3.1 as follows:

a) Authentication (not used when dot11OCBEnabled is true)

b) Deauthentication (not used when dot11OCBEnabled is true)

c) Data confidentiality (not used when dot11OCBEnabled is true)=94

   o  Flag dot11OCBActivated set to true

   The following message exchange diagram illustrates a comparison

   between traditional 802.11 and 802.11 in OCB mode.  The 'Data'



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   messages can be IP messages such as the messages used in Stateless or

   Stateful Address Auto-Configuration, or other IP messages.


[Sri] Lets separate the discussion on IP Address configuration using SLAAC/=
DHCP on such links from the above description. The Data packets here can be=
 application packets such as HTTP or other packets. May be additional discu=
ssion is needed on the IP address configuration on 802.11-OCB links.


Other

   802.11 management and control frames (non IP) may be transmitted, as

   specified in the 802.11 standard.  For information, the names of

   these messages as currently specified by the 802.11 standard are

   listed in https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211o=
cb-04#appendix-D.






     STA                    AP              STA1                   STA2

     |                      |               |                      |

     |<------ Beacon -------|               |<------ Data -------->|

     |                      |               |                      |

     |---- Probe Req. ----->|               |<------ Data -------->|

     |<--- Probe Res. ------|               |                      |

     |                      |               |<------ Data -------->|

     |---- Auth Req. ------>|               |                      |

     |<--- Auth Res. -------|               |<------ Data -------->|

     |                      |               |                      |

     |---- Asso Req. ------>|               |<------ Data -------->|

     |<--- Asso Res. -------|               |                      |

     |                      |               |<------ Data -------->|

     |<------ Data -------->|               |                      |

     |<------ Data -------->|               |<------ Data -------->|

    (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode


   The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010

   [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref=
-ieee802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007,

   titled "Amendment 6: Wireless Access in Vehicular Environments".

   Since then, this amendment has been included in IEEE 802.11(TM)-2012

   [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref=
-ieee802.11-2012], titled "IEEE Standard for Information technology--

   Telecommunications and information exchange between systems Local and

   metropolitan area networks--Specific requirements Part 11: Wireless

   LAN Medium Access Control (MAC) and Physical Layer (PHY)

   Specifications"; the modifications are diffused throughout various

   sections (e.g. the Time Advertisement message described in the

   earlier 802.11 (TM) p amendment is now described in section 'Frame

   formats', and the operation outside the context of a BSS described in

   section 'MLME').

   In document 802.11-2012, specifically anything referring

   "OCBActivated", or "outside the context of a basic service set" is

   actually referring to the 802.11p aspects introduced to 802.11.  Note

   that in earlier 802.11p documents the term "OCBEnabled" was used

   instead of te current "OCBActivated".





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   In order to delineate the aspects introduced by 802.11 OCB to 802.11,

   we refer to the earlier [https://tools.ietf.org/html/draft-ietf-ipwave-i=
pv6-over-80211ocb-04#ref-ieee802.11p-2010].  The amendment is

   concerned with vehicular communications, where the wireless link is

   similar to that of Wireless LAN (using a PHY layer specified by

   802.11a/b/g/n), but which needs to cope with the high mobility factor

   inherent in scenarios of communications between moving vehicles, and

   between vehicles and fixed infrastructure deployed along roads.

   While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is

   concerned more with MAC modifications, and a little with PHY

   modifications; the others are mainly about PHY modifications.  It is

   possible in practice to combine a 'p' MAC with an 'a' PHY by

   operating outside the context of a BSS with OFDM at 5.4GHz.

   The 802.11 OCB links are specified to be compatible as much as

   possible with the behaviour of 802.11a/b/g/n and future generation

   IEEE WLAN links.  From the IP perspective, an 802.11 OCB MAC layer

   offers practically the same interface to IP as the WiFi and Ethernet

   layers do (802.11a/b/g/n and 802.3).


[Sri] A packet sent from a vehicle=92s OBU is received by a single RSU, or =
multiple RSU=92s? How does the link-layer resolution happen?

[Fygs] Assuming that:

a)     If there aresingle or multiple RSUsin the communication range and it=
 is amulticast message,the single RSU or RSUs in the comm. range will recei=
ve it (eventually). There is no resolution at the link layer. The RSU(s) wi=
ll determine their =93interest=94 based on the content of the message at th=
e higher layers (application);

b)     If there are single or multiple RSUs in the communication rand and i=
t isunicast message, then the link-layer resolves by thedestination MAC add=
ress.

   To support this similarity statement (IPv6 is layered on top of LLC

   on top of 802.11 OCB similarly as on top of LLC on top of

   802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to

   analyze the differences between 802.11 OCB and 802.11 specifications.

   Whereas the 802.11p amendment specifies relatively complex and

   numerous changes to the MAC layer (and very little to the PHY layer),

   we note there are only a few characteristics which may be important

   for an implementation transmitting IPv6 packets on 802.11 OCB links.

   In the list below, the only 802.11 OCB fundamental points which

   influence IPv6 are the OCB operation and the 12Mbit/s maximum which

   may be afforded by the IPv6 applications.


[Sri] I am really not sure how link throughput (12Mbps) relates to "IPv6 su=
pport on OCB links".

[Fygs] First of all there is guarantee of 12 Mbps throughput because of col=
lisions and other interferences, 12 Mbps data rate was probably intended.

The data rates for 20 MHz channel spacingare6, 9, 12, 18, 24, 36,48, and 54=
 Mb/s with mandatory support of 6, 12, and 24 Mbps;

Data rates for 10 MHz channel spacing are3, 4.5, 6, 9, 12, 18, 24, and 27 M=
b/s.with mandatory support of  3, 6, and 12 Mb/s.


   o  Operation Outside the Context of a BSS (OCB): the (earlier

      802.11p) 802.11-OCB links are operated without a Basic Service Set

      (BSS).  This means that the frames IEEE 802.11 Beacon, Association

      Request/Response, Authentication Request/Response, and similar,

      are not used.  The used identifier of BSS (BSSID) has a

      hexadecimal value always 0xffffffffffff (48 '1' bits, represented

      as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard'

      BSSID), as opposed to an arbitrary BSSID value set by

      administrator (e.g.  'My-Home-AccessPoint').  The OCB operation -

      namely the lack of beacon-based scanning and lack of

      authentication - has a potentially strong impact on the use of the

      Mobile IPv6 protocol [https://tools.ietf.org/html/rfc6275] and on the=
 protocols for IP layer

      security [https://tools.ietf.org/html/rfc4301].


[Sri] The document till now has been arguing heavily on how IPv6 operates s=
o naturally on these links and now I see discussion on =93Impact to a high-=
level protocol such as MIPv6=94. You may want to fix the earlier text. In a=
ny case,  the absence of link-layer security practically impacts every appl=
ication, not just MIPv6.  Also, MIPv6 does not make any assumptions on the =
link-layer security.  Also, the the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes=
 the messages readable by all other RSU=92s in proximity. I think the discu=
ssion on the nature of the link, who all see=92s the messages.. how L2 addr=
esses are resolved is not explained clearly.



   o  Timing Advertisement: is a new message defined in 802.11-OCB,

      which does not exist in 802.11a/b/g/n.  This message is used by



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      stations to inform other stations about the value of time.  It is

      similar to the time as delivered by a GNSS system (Galileo, GPS,

      ...) or by a cellular system.  This message is optional for

      implementation.  At the date of writing, an experienced reviewer

      considers that currently no field testing has used this message.

      Another implementor considers this feature implemented in an

      initial manner.  In the future, it is speculated that this message

      may be useful for very simple devices which may not have their own

      hardware source of time (Galileo, GPS, cellular network), or by

      vehicular devices situated in areas not covered by such network

      (in tunnels, underground, outdoors but shaded by foliage or

      buildings, in remote areas, etc.)


[Sri] The first part explaining Timing Advertisement messages is great, but=
 the rest of the commentary is unnecessary and not needed. We don=92t specu=
late the protocol adoption success in IETF specifications, or about the exp=
erience level of the =93reviewer" :)

[Fygs]: Absolutely agree.

   o  Frequency range: this is a characteristic of the PHY layer, with

      almost no impact to the interface between MAC and IP.  However, it

      is worth considering that the frequency range is regulated by a

      regional authority (ARCEP, ETSI, FCC, etc.); as part of the

      regulation process, specific applications are associated with

      specific frequency ranges.  In the case of 802.11-OCB, the

      regulator associates a set of frequency ranges, or slots within a

      band, to the use of applications of vehicular communications, in a

      band known as "5.9GHz".  This band is "5.9GHz" which is different

      from the bands "2.4GHz" or "5GHz" used by Wireless LAN.  However,

      as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz"

      bands is exempt from owning a license in EU (in US the 5.9GHz is a

      licensed band of spectrum; for the the fixed infrastructure an

      explicit FCC autorization is required; for an onboard device a

      'licensed-by-rule' concept applies: rule certification conformity

      is required); however technical conditions are different than

      those of the bands "2.4GHz" or "5GHz".  On one hand, the allowed

      power levels, and implicitly the maximum allowed distance between

      vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20

      dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum

      distance of approximately 1km, compared to approximately 50m.  On

      the other hand, specific conditions related to congestion

      avoidance, jamming avoidance, and radar detection are imposed on

      the use of DSRC (in US) and on the use of frequencies for

      Intelligent Transportation Systems (in EU), compared to Wireless

      LAN (802.11a/b/g/n).

   o  Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB,

      as opposed to IPv6 not being prohibited on any channel on which

      802.11a/b/g/n runs:

      *  Some channels are reserved for safety communications; the IPv6

         packets should not be sent on these channels.





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      *  At the time of writing, the prohibition is explicit at higher

         layer protocols providing services to the application; these

         higher layer protocols are specified in IEEE 1609 documents.

      *  National or regional specifications and regulations specify the

         use of different channels; these regulations must be followed.

   o  'Half-rate' encoding: as the frequency range, this parameter is

      related to PHY, and thus has not much impact on the interface

      between the IP layer and the MAC layer.

   o  In vehicular communications using 802.11-OCB links, there are

      strong privacy requirements with respect to addressing.  While the

      802.11-OCB standard does not specify anything in particular with

      respect to MAC addresses, in these settings there exists a strong

      need for dynamic change of these addresses (as opposed to the non-

      vehicular settings - real wall protection - where fixed MAC

      addresses do not currently pose some privacy risks).  This is

      further described in section https://tools.ietf.org/html/draft-ietf-i=
pwave-ipv6-over-80211ocb-04#section-7.  A relevant function is

      described in IEEE 1609.3-2016 [https://tools.ietf.org/html/draft-ietf=
-ipwave-ipv6-over-80211ocb-04#ref-ieee1609.3], clause 5.5.1 and IEEE

      1609.4-2016 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-=
80211ocb-04#ref-ieee1609.4], clause 6.7.

   Other aspects particular to 802.11-OCB which are also particular to

   802.11 (e.g. the 'hidden node' operation) may have an influence on

   the use of transmission of IPv6 packets on 802.11-OCB networks.  The

   subnet structure which may be assumed in 802.11-OCB networks is

   strongly influenced by the mobility of vehicles.


[Sri] Per my earlier comment, the link model, addressing ..etc needs to be =
explained in more detail. It is not clear what exactly the =93subnet struct=
ure=94 that is assumed in 802.11-OCB.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.  Layering of IPv6 over 802.11-OCB as over Ethernet


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.1.  Maximum Transmission Unit (MTU)


   The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is

   the same value as IPv6 packets on Ethernet links, as specified in

   [https://tools.ietf.org/html/rfc2464].  This value of the MTU respects t=
he recommendation that

   every link in the Internet must have a minimum MTU of 1280 octets

   (stated in [https://tools.ietf.org/html/rfc2460], and the recommendation=
s therein, especially

   with respect to fragmentation).  If IPv6 packets of size larger than

   1500 bytes are sent on an 802.11-OCB interface card then the IP stack

   will fragment.  In case there are IP fragments, the field "Sequence

   number" of the 802.11 Data header containing the IP fragment field is

   increased.

   Non-IP packets such as WAVE Short Message Protocol (WSMP) can be

   delivered on 802.11-OCB links.  Specifications of these packets are

   out of scope of this document, and do not impose any limit on the MTU

   size, allowing an arbitrary number of 'containers'.  Non-IP packets

   such as ETSI 'geonet' packets have an MTU of 1492 bytes.



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   The Equivalent Transmit Time on Channel is a concept that may be used

   as an alternative to the MTU concept.  A rate of transmission may be

   specified as well.  The ETTC, rate and MTU may be in direct

   relationship.

[Sri] The last paragraph needs some additional context. Did 802.11-OCB intr=
oduce ETTC concept?

[Fygs] NO !


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.2.  Frame Format


   IP packets are transmitted over 802.11-OCB as standard Ethernet

   packets.  As with all 802.11 frames, an Ethernet adaptation layer is

   used with 802.11-OCB as well.  This Ethernet Adaptation Layer

   performing 802.11-to-Ethernet is described in https://tools.ietf.org/htm=
l/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.2.1.  The

   Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD,

   or otherwise #86DD).

   The Frame format for transmitting IPv6 on 802.11-OCB networks is the

   same as transmitting IPv6 on Ethernet networks, and is described in

   https://tools.ietf.org/html/rfc2464#section-3.  The frame format for tra=
nsmitting IPv6

   packets over Ethernet is illustrated below:


                    0                   1

                    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5

                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    |          Destination          |

                    +-                             -+

                    |            Ethernet           |

                    +-                             -+

                    |            Address            |

                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    |             Source            |

                    +-                             -+

                    |            Ethernet           |

                    +-                             -+

                    |            Address            |

                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|

                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    |             IPv6              |

                    +-                             -+

                    |            header             |

                    +-                             -+

                    |             and               |

                    +-                             -+

                    /            payload ...        /

                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    (Each tic mark represents one bit.)





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   Ethernet II Fields:

   Destination Ethernet Address

      the MAC destination address.

   Source Ethernet Address

      the MAC source address.

   1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1

      binary representation of the EtherType value 0x86DD.

   IPv6 header and payload

      the IPv6 packet containing IPv6 header and payload.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.2.1.  Ethernet Adaptation Layer


   In general, an 'adaptation' layer is inserted between a MAC layer and

   the Networking layer.  This is used to transform some parameters

   between their form expected by the IP stack and the form provided by

   the MAC layer.  For example, an 802.15.4 adaptation layer may perform

   fragmentation and reassembly operations on a MAC whose maximum Packet

   Data Unit size is smaller than the minimum MTU recognized by the IPv6

   Networking layer.  Other examples involve link-layer address

   transformation, packet header insertion/removal, and so on.

   An Ethernet Adaptation Layer makes an 802.11 MAC look to IP

   Networking layer as a more traditional Ethernet layer.  At reception,

   this layer takes as input the IEEE 802.11 Data Header and the

   Logical-Link Layer Control Header and produces an Ethernet II Header.

   At sending, the reverse operation is performed.


 +--------------------+------------+-------------+---------+-----------+

 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer|

 +--------------------+------------+-------------+---------+-----------+

  \                               /                         \         /

    -----------------------------                             --------

                   ^---------------------------------------------/

                   |

           802.11-to-Ethernet Adaptation Layer

                   |

                   v

 +---------------------+-------------+---------+

 | Ethernet II Header  | IPv6 Header | Payload |

 +---------------------+-------------+---------+






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   The Receiver and Transmitter Address fields in the 802.11 Data Header

   contain the same values as the Destination and the Source Address

   fields in the Ethernet II Header, respectively.  The value of the

   Type field in the LLC Header is the same as the value of the Type

   field in the Ethernet II Header.

   The ".11 Trailer" contains solely a 4-byte Frame Check Sequence.

   The Ethernet Adaptation Layer performs operations in relation to IP

   fragmentation and MTU.  One of these operations is briefly described

   in section https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211=
ocb-04#section-5.1.

   In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11

   Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in

   the following figure:


+--------------------+-------------+-------------+---------+-----------+

| 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 Trailer|

+--------------------+-------------+-------------+---------+-----------+

or

+--------------------+-------------+-------------+---------+-----------+

| 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|

+--------------------+-------------+-------------+---------+-----------+


   The distinction between the two formats is given by the value of the

   field "Type/Subtype".  The value of the field "Type/Subtype" in the

   802.11 Data header is 0x0020.  The value of the field "Type/Subtype"

   in the 802.11 QoS header is 0x0028.

   The mapping between qos-related fields in the IPv6 header (e.g.

   "Traffic Class", "Flow label") and fields in the "802.11 QoS Data

   Header" (e.g.  "QoS Control") are not specified in this document.

   Guidance for a potential mapping is provided in

   [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref=
-I-D.ietf-tsvwg-ieee-802-11], although it is not specific to OCB

   mode.



[Sri] The applicability of the QoS mapping draft to 802.11-OCB needs furthe=
r investigation, IMO.

[Fygs] I am not familiar with QoS control of IPv6.  As for the OCB MAC QoS =
it is somewhat involved.  It is based ontransmission priority of MAC frames=
.  A higher priority frame is intended to be transmitted ahead of lower pri=
ority frames.  If a detail process is required, please, let me know and I w=
ould provide the text.


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.3.  Link-Local Addresses


   The link-local address of an 802.11-OCB interface is formed in the

   same manner as on an Ethernet interface.  This manner is described in

   https://tools.ietf.org/html/rfc2464#section-5.



[Sri] Does this go against the 8064 recommendation on Interface identifier =
generation?

May be RFC7217 for interface identifier generation in conjunction with the =
link-local address generation per RFC2464





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https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.4.  Address Mapping


   For unicast as for multicast, there is no change from the unicast and

   multicast address mapping format of Ethernet interfaces, as defined

   by sections https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-8021=
1ocb-04#section-6 and https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-ov=
er-80211ocb-04#section-7 of [https://tools.ietf.org/html/rfc2464].



[Sri] RFC6085 specified mapping is also relevant; If the communication peer=
s are aware that there is only one peer, it should apply 6085 specified map=
ping. That mode is relevant for 802.11-OCB types links as well.


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.4.1.  Address Mapping -- Unicast


   The procedure for mapping IPv6 unicast addresses into Ethernet link-

   layer addresses is described in [https://tools.ietf.org/html/rfc4861].  =
The Source/Target Link-

   layer Address option has the following form when the link-layer is

   Ethernet.

[Sri] I thought, mapping of IPv6 unicast addresses to Ethernet link-layer a=
ddresses is specified in section 6, of RFC2464 and not in RFC4861.



                      0                   1

                      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5

                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     |     Type      |    Length     |

                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     |                               |

                     +-          Ethernet           -+

                     |                               |

                     +-           Address           -+

                     |                               |

                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Option fields:

   Type

      1 for Source Link-layer address.

      2 for Target Link-layer address.

   Length

      1 (in units of 8 octets).

   Ethernet Address

      The 48 bit Ethernet IEEE 802 address, in canonical bit order.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.4.2.  Address Mapping -- Multicast


   IPv6 protocols often make use of IPv6 multicast addresses in the

   destination field of IPv6 headers.  For example, an ICMPv6 link-

   scoped Neighbor Advertisement is sent to the IPv6 address ff02::1

   denoted "all-nodes" address.  When transmitting these packets on

   802.11-OCB links it is necessary to map the IPv6 address to a MAC

   address.




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   The same mapping requirement applies to the link-scoped multicast

   addresses of other IPv6 protocols as well.  In DHCPv6, the

   "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF the

   "All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped

   on a multicast MAC address.

   An IPv6 packet with a multicast destination address DST, consisting

   of the sixteen octets DST[1] through DST[16], is transmitted to the

   IEEE 802.11-OCB MAC multicast address whose first two octets are the

   value 0x3333 and whose last four octets are the last four octets of

   DST.

[Sri] Please add a reference to Section 7, RFC4861 and also RFC6085. In gen=
eral, for both unicast and multicast, you may want to clearly say that this=
 is per the existing specs and duplicated here for convenience.

                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|

                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     |   DST[13]     |   DST[14]     |

                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     |   DST[15]     |   DST[16]     |

                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   A Group ID TBD of length 112bits may be requested from IANA; this

   Group ID signifies "All 80211OCB Interfaces Address".  Only the least

   32 significant bits of this "All 80211OCB Interfaces Address" will be

   mapped to and from a MAC multicast address.

   Transmitting IPv6 packets to multicast destinations over 802.11 links

   proved to have some performance issues

   [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref=
-I-D.perkins-intarea-multicast-ieee802].  These issues may be

   exacerbated in OCB mode.  Solutions for these problems should

   consider the OCB mode of operation.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.5.  Stateless Autoconfiguration


   The Interface Identifier for an 802.11-OCB interface is formed using

   the same rules as the Interface Identifier for an Ethernet interface;

   this is described in https://tools.ietf.org/html/rfc2464#section-4.  No =
changes are needed,

   but some care must be taken when considering the use of the SLAAC

   procedure.


[Sri] Per my earlier comment, please refer to the current recommendation on=
 interface-identifier generation and its use in link-local, global or other=
 addresses.


   The bits in the the interface identifier have no generic meaning and

   the identifier should be treated as an opaque value.  The bits

   'Universal' and 'Group' in the identifier of an 802.11-OCB interface

   are significant, as this is an IEEE link-layer address.  The details

   of this significance are described in [https://tools.ietf.org/html/draft=
-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.ietf-6man-ug].





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   As with all Ethernet and 802.11 interface identifiers ([https://tools.ie=
tf.org/html/rfc7721]),

   the identifier of an 802.11-OCB interface may involve privacy risks.

   A vehicle embarking an On-Board Unit whose egress interface is

   802.11-OCB may expose itself to eavesdropping and subsequent

   correlation of data; this may reveal data considered private by the

   vehicle owner; there is a risk of being tracked; see the privacy

   considerations described in https://tools.ietf.org/html/draft-ietf-ipwav=
e-ipv6-over-80211ocb-04#appendix-C.


[Sri] I think there are other security issues here; the absence of link-lay=
er security opens up Mac-spoofing and IP address hijacking.  That should be=
 mentioned.


   If stable Interface Identifiers are needed in order to form IPv6

   addresses on 802.11-OCB links, it is recommended to follow the

   recommendation in [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-ov=
er-80211ocb-04#ref-I-D.ietf-6man-default-iids].

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.6.  Subnet Structure


   The 802.11 networks in OCB mode may be considered as 'ad-hoc'

   networks.  The addressing model for such networks is described in

   [https://tools.ietf.org/html/rfc5889].


[Sri] Per my earlier comment, there is no system level view of the network =
where 802.11-OCB links are used. So, in the absence of such discussion So, =
I am not sure what part of RFC5889 is applicable here. For example, link-lo=
cal addresses may just work fine.


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-6.  Example IPv6 Packet captured over a IEEE 802.11-OCB link


   We remind that a main goal of this document is to make the case that

   IPv6 works fine over 802.11-OCB networks.  Consequently, this section

   is an illustration of this concept and thus can help the implementer

   when it comes to running IPv6 over IEEE 802.11-OCB.  By way of

   example we show that there is no modification in the headers when

   transmitted over 802.11-OCB networks - they are transmitted like any

   other 802.11 and Ethernet packets.

   We describe an experiment of capturing an IPv6 packet on an

   802.11-OCB link.  In this experiment, the packet is an IPv6 Router

   Advertisement.  This packet is emitted by a Router on its 802.11-OCB

   interface.  The packet is captured on the Host, using a network

   protocol analyzer (e.g.  Wireshark); the capture is performed in two

   different modes: direct mode and 'monitor' mode.  The topology used

   during the capture is depicted below.


              +--------+                                +-------+

              |        |        802.11-OCB Link         |       |

           ---| Router |--------------------------------| Host  |

              |        |                                |       |

              +--------+                                +-------+


   During several capture operations running from a few moments to

   several hours, no message relevant to the BSSID contexts were

   captured (no Association Request/Response, Authentication Req/Resp,




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   Beacon).  This shows that the operation of 802.11-OCB is outside the

   context of a BSSID.

   Overall, the captured message is identical with a capture of an IPv6

   packet emitted on a 802.11b interface.  The contents are precisely

   similar.


[Sri] I suggest moving this discussion under the section =93Implementation =
Status=94, which will eventually be removed from the RFC. There is nothing =
new here. This are details on experimentation. But, if you think there is s=
ome useful information  such as discussion on Capture mode ..etc, you may w=
ant to move this entire section to Appendix. Implementors may use these too=
ls for verification.



https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-6.1.  Capture in Monitor Mode


   The IPv6 RA packet captured in monitor mode is illustrated below.

   The radio tap header provides more flexibility for reporting the

   characteristics of frames.  The Radiotap Header is prepended by this

   particular stack and operating system on the Host machine to the RA

   packet received from the network (the Radiotap Header is not present

   on the air).  The implementation-dependent Radiotap Header is useful

   for piggybacking PHY information from the chip's registers as data in

   a packet understandable by userland applications using Socket

   interfaces (the PHY interface can be, for example: power levels, data

   rate, ratio of signal to noise).

   The packet present on the air is formed by IEEE 802.11 Data Header,

   Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.



     Radiotap Header v0

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |Header Revision|  Header Pad   |    Header length              |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                         Present flags                         |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Data Rate     |             Pad                               |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IEEE 802.11 Data Header

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |  Type/Subtype and Frame Ctrl  |          Duration             |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                      Receiver Address...

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     ... Receiver Address           |      Transmitter Address...

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     ... Transmitter Address                                        |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                            BSS Id...

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     ... BSS Id                     |  Frag Number and Seq Number   |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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     Logical-Link Control Header

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |      DSAP   |I|     SSAP    |C| Control field | Org. code...

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     ... Organizational Code        |             Type              |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |Version| Traffic Class |           Flow Label                  |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |         Payload Length        |  Next Header  |   Hop Limit   |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                                                               |

     +                                                               +

     |                                                               |

     +                         Source Address                        +

     |                                                               |

     +                                                               +

     |                                                               |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                                                               |

     +                                                               +

     |                                                               |

     +                      Destination Address                      +

     |                                                               |

     +                                                               +

     |                                                               |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |     Type      |     Code      |          Checksum             |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                         Reachable Time                        |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                          Retrans Timer                        |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |   Options ...

     +-+-+-+-+-+-+-+-+-+-+-+-


   The value of the Data Rate field in the Radiotap header is set to 6

   Mb/s.  This indicates the rate at which this RA was received.





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   The value of the Transmitter address in the IEEE 802.11 Data Header

   is set to a 48bit value.  The value of the destination address is

   33:33:00:00:00:1 (all-nodes multicast address).  The value of the BSS

   Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network

   protocol analyzer as being "broadcast".  The Fragment number and

   sequence number fields are together set to 0x90C6.

   The value of the Organization Code field in the Logical-Link Control

   Header is set to 0x0, recognized as "Encapsulated Ethernet".  The

   value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise

   #86DD), recognized as "IPv6".

   A Router Advertisement is periodically sent by the router to

   multicast group address ff02::1.  It is an icmp packet type 134.  The

   IPv6 Neighbor Discovery's Router Advertisement message contains an

   8-bit field reserved for single-bit flags, as described in [https://tool=
s.ietf.org/html/rfc4861].

   The IPv6 header contains the link local address of the router

   (source) configured via EUI-64 algorithm, and destination address set

   to ff02::1.  Recent versions of network protocol analyzers (e.g.

   Wireshark) provide additional informations for an IP address, if a

   geolocalization database is present.  In this example, the

   geolocalization database is absent, and the "GeoIP" information is

   set to unknown for both source and destination addresses (although

   the IPv6 source and destination addresses are set to useful values).

   This "GeoIP" can be a useful information to look up the city,

   country, AS number, and other information for an IP address.

[Sri] Not sure, why all of this text should be in the specification.

   The Ethernet Type field in the logical-link control header is set to

   0x86dd which indicates that the frame transports an IPv6 packet.  In

   the IEEE 802.11 data, the destination address is 33:33:00:00:00:01

   which is he corresponding multicast MAC address.  The BSS id is a

   broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link

   duration between vehicles and the roadside infrastructure, there is

   no need in IEEE 802.11-OCB to wait for the completion of association

   and authentication procedures before exchanging data.  IEEE

   802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)

   and may start communicating as soon as they arrive on the

  communication channel.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-6.2. Capture in Normal Mode


   The same IPv6 Router Advertisement packet described above (monitor

   mode) is captured on the Host, in the Normal mode, and depicted

   below.






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    Ethernet II Header

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                       Destination...

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     ...Destination                 |           Source...

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     ...Source                                                      |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |          Type                 |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     IPv6 Base Header

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |Version| Traffic Class |           Flow Label                  |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |         Payload Length        |  Next Header  |   Hop Limit   |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                                                               |

     +                                                               +

     |                                                               |

     +                         Source Address                        +

     |                                                               |

     +                                                               +

     |                                                               |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                                                               |

     +                                                               +

     |                                                               |

     +                      Destination Address                      +

     |                                                               |

     +                                                               +

     |                                                               |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Router Advertisement

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |     Type      |     Code      |          Checksum             |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Cur Hop Limit |M|O|  Reserved |       Router Lifetime         |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                         Reachable Time                        |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                          Retrans Timer                        |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |   Options ...

     +-+-+-+-+-+-+-+-+-+-+-+-





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   One notices that the Radiotap Header is not prepended, and that the

   IEEE 802.11 Data Header and the Logical-Link Control Headers are not

   present.  On another hand, a new header named Ethernet II Header is

   present.

   The Destination and Source addresses in the Ethernet II header

   contain the same values as the fields Receiver Address and

   Transmitter Address present in the IEEE 802.11 Data Header in the

   "monitor" mode capture.

   The value of the Type field in the Ethernet II header is 0x86DD

   (recognized as "IPv6"); this value is the same value as the value of

   the field Type in the Logical-Link Control Header in the "monitor"

   mode capture.

   The knowledgeable experimenter will no doubt notice the similarity of

   this Ethernet II Header with a capture in normal mode on a pure

   Ethernet cable interface.

   It may be interpreted that an Adaptation layer is inserted in a pure

   IEEE 802.11 MAC packets in the air, before delivering to the

   applications.  In detail, this adaptation layer may consist in

   elimination of the Radiotap, 802.11 and LLC headers and insertion of

   the Ethernet II header.  In this way, it can be stated that IPv6 runs

   naturally straight over LLC over the 802.11-OCB MAC layer, as shown

   by the use of the Type 0x86DD, and assuming an adaptation layer

   (adapting 802.11 LLC/MAC to Ethernet II header).

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-7.  Security Considerations


   Any security mechanism at the IP layer or above that may be carried

   out for the general case of IPv6 may also be carried out for IPv6

   operating over 802.11-OCB.

   802.11-OCB does not provide any cryptographic protection, because it

   operates outside the context of a BSS (no Association Request/

   Response, no Challenge messages).  Any attacker can therefore just

   sit in the near range of vehicles, sniff the network (just set the

   interface card's frequency to the proper range) and perform attacks

   without needing to physically break any wall.  Such a link is way

   less protected than commonly used links (wired link or protected

   802.11).

[Sri] Per my earlier comment, there is more than one attack vector possible

1.) Absence of link-layer security and the potential for mac address spoofi=
ng

2.) IP address / Session hijacking

3.) Data privacy per your text


   At the IP layer, IPsec can be used to protect unicast communications,

   and SeND can be used for multicast communications.

[Sri] IPSec can be used for protecting both multicast or unicast communicat=
ion; RFC-5374 with GDOI.



 If no protection

   is used by the IP layer, upper layers should be protected.

   Otherwise, the end-user or system should be warned about the risks

   they run.



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   As with all Ethernet and 802.11 interface identifiers, there may

   exist privacy risks in the use of 802.11-OCB interface identifiers.

   Moreover, in outdoors vehicular settings, the privacy risks are more

   important than in indoors settings.  New risks are induced by the

   possibility of attacker sniffers deployed along routes which listen

   for IP packets of vehicles passing by.  For this reason, in the

   802.11-OCB deployments, there is a strong necessity to use protection

   tools such as dynamically changing MAC addresses.  This may help

   mitigate privacy risks to a certain level.  On another hand, it may

   have an impact in the way typical IPv6 address auto-configuration is

   performed for vehicles (SLAAC would rely on MAC addresses amd would

   hence dynamically change the affected IP address), in the way the

   IPv6 Privacy addresses were used, and other effects.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-8.  IANA Considerations


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-9.  Contributors


   Romain Kuntz contributed extensively about IPv6 handovers between

   links running outside the context of a BSS (802.11-OCB links).

   Tim Leinmueller contributed the idea of the use of IPv6 over

   802.11-OCB for distribution of certificates.

   Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey

   Voronov provided significant feedback on the experience of using IP

   messages over 802.11-OCB in initial trials.

   Michelle Wetterwald contributed extensively the MTU discussion,

   offered the ETSI ITS perspective, and reviewed other parts of the

   document.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-10.  Acknowledgements


   The authors would like to thank Witold Klaudel, Ryuji Wakikawa,

   Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan

   Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray

   Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,

   Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,

   Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,

   Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and

   William Whyte.  Their valuable comments clarified certain issues and

   generally helped to improve the document.

   Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB

   drivers for linux and described how.





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   For the multicast discussion, the authors would like to thank Owen

   DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and

   participants to discussions in network working groups.

   The authours would like to thank participants to the Birds-of-

   a-Feather "Intelligent Transportation Systems" meetings held at IETF

   in 2016.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-11.  References


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-11.1.  Normative References


   [I-D.ietf-6man-default-iids]

              Gont, F., Cooper, A., Thaler, D., and S. LIU,

              "Recommendation on Stable IPv6 Interface Identifiers",

              https://tools.ietf.org/html/draft-ietf-6man-default-iids-16 (=
work in progress),

              September 2016.

   [I-D.ietf-6man-ug]

              Carpenter, B. and S. Jiang, "Significance of IPv6

              Interface Identifiers", https://tools.ietf.org/html/draft-iet=
f-6man-ug-06 (work in

              progress), December 2013.

   [I-D.ietf-tsvwg-ieee-802-11]

              Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE

              802.11 Mapping", https://tools.ietf.org/html/draft-ietf-tsvwg=
-ieee-802-11-06 (work in

              progress), August 2017.

   [RFC1042]  Postel, J. and J. Reynolds, "Standard for the transmission

              of IP datagrams over IEEE 802 networks", STD 43, https://tool=
s.ietf.org/html/rfc1042,

              DOI 10.17487/RFC1042, February 1988, .

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate

              Requirement Levels", https://tools.ietf.org/html/bcp14, https=
://tools.ietf.org/html/rfc2119,

              DOI 10.17487/RFC2119, March 1997, .

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6

              (IPv6) Specification", https://tools.ietf.org/html/rfc2460, D=
OI 10.17487/RFC2460,

              December 1998, .

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet

              Networks", https://tools.ietf.org/html/rfc2464, DOI 10.17487/=
RFC2464, December 1998,

              .






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   [RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.

              Thubert, "Network Mobility (NEMO) Basic Support Protocol",

              https://tools.ietf.org/html/rfc3963, DOI 10.17487/RFC3963, Ja=
nuary 2005,

              .

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,

              "Randomness Requirements for Security", https://tools.ietf.or=
g/html/bcp106, https://tools.ietf.org/html/rfc4086,

             DOI 10.17487/RFC4086, June 2005, .

  [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the

             Internet Protocol", https://tools.ietf.org/html/rfc4301, DOI 1=
0.17487/RFC4301,

             December 2005, .

   [RFC4429]  Moore, N., "Optimistic Duplicate Address Detection (DAD)

              for IPv6", https://tools.ietf.org/html/rfc4429, DOI 10.17487/=
RFC4429, April 2006,

              .

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,

              "Neighbor Discovery for IP version 6 (IPv6)", https://tools.i=
etf.org/html/rfc4861,

              DOI 10.17487/RFC4861, September 2007, .

   [RFC5889]  Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing

              Model in Ad Hoc Networks", https://tools.ietf.org/html/rfc588=
9, DOI 10.17487/RFC5889,

              September 2010, .

   [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility

              Support in IPv6", https://tools.ietf.org/html/rfc6275, DOI 10=
.17487/RFC6275, July

              2011, .

   [RFC6775]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.

              Bormann, "Neighbor Discovery Optimization for IPv6 over

              Low-Power Wireless Personal Area Networks (6LoWPANs)",

              https://tools.ietf.org/html/rfc6775, DOI 10.17487/RFC6775, No=
vember 2012,

              .

   [RFC7721]  Cooper, A., Gont, F., and D. Thaler, "Security and Privacy

              Considerations for IPv6 Address Generation Mechanisms",

              https://tools.ietf.org/html/rfc7721, DOI 10.17487/RFC7721, Ma=
rch 2016,

              .

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-11.2.  Informative References









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   [fcc-cc]   "'Report and Order, Before the Federal Communications

              Commission Washington, D.C. 20554', FCC 03-324, Released

              on February 10, 2004, document FCC-03-324A1.pdf, document

              freely available at URL

              http://www.its.dot.gov/exit/fcc_edocs.htm downloaded on

              October 17th, 2013.".

   [fcc-cc-172-184]

              "'Memorandum Opinion and Order, Before the Federal

              Communications Commission Washington, D.C. 20554', FCC

              06-10, Released on July 26, 2006, document FCC-

              06-110A1.pdf, document freely available at URL

              http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A=
1.pdf

              http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A=
1.pdf downloaded on June 5th, 2014.".

   [I-D.jeong-ipwave-vehicular-networking-survey]

              Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M.

              Wetterwald, "Survey on IP-based Vehicular Networking for

              Intelligent Transportation Systems", https://tools.ietf.org/h=
tml/draft-jeong-ipwave-vehicular-networking-survey-03

              https://tools.ietf.org/html/draft-jeong-ipwave-vehicular-netw=
orking-survey-03 (work in progress), June

              2017.

   [I-D.perkins-intarea-multicast-ieee802]

              Perkins, C., Stanley, D., Kumari, W., and J. Zuniga,

              "Multicast Considerations over IEEE 802 Wireless Media",

              https://tools.ietf.org/html/draft-perkins-intarea-multicast-i=
eee802-03 (work in

              progress), July 2017.

   [I-D.petrescu-its-scenarios-reqs]

              Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel,

              "Scenarios and Requirements for IP in Intelligent

              Transportation Systems", https://tools.ietf.org/html/draft-pe=
trescu-its-scenarios-reqs-03

              https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs=
-03 (work in progress), October 2013.

   [ieee1609.2]

              "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access

              in Vehicular Environments (WAVE) -- Security Services for

              Applications and Management Messages.  Example URL

              http://ieeexplore.ieee.org/document/7426684/ accessed on

              August 17th, 2017.".

   [ieee1609.3]

              "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access

              in Vehicular Environments (WAVE) -- Networking Services.

              Example URL http://ieeexplore.ieee.org/document/7458115/acces=
sed

              http://ieeexplore.ieee.org/document/7458115/accessed on Augus=
t 17th, 2017.".





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   [ieee1609.4]

              "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access

              in Vehicular Environments (WAVE) -- Multi-Channel

              Operation.  Example URL

              http://ieeexplore.ieee.org/document/7435228/ accessed on

              August 17th, 2017.".

   [ieee802.11-2012]

              "802.11-2012 - IEEE Standard for Information technology--

              Telecommunications and information exchange between

              systems Local and metropolitan area networks--Specific

              requirements Part 11: Wireless LAN Medium Access Control

              (MAC) and Physical Layer (PHY) Specifications.  Downloaded

              on October 17th, 2013, from IEEE Standards, document

              freely available at URL

              http://standards.ieee.org/findstds/standard/802.11-2012.html

              http://standards.ieee.org/findstds/standard/802.11-2012.html =
retrieved on October 17th,

              2013.".

   [ieee802.11p-2010]

              "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information

              Technology - Telecommunications and information exchange

              between systems - Local and metropolitan area networks -

              Specific requirements, Part 11: Wireless LAN Medium Access

              Control (MAC) and Physical Layer (PHY) Specifications,

              Amendment 6: Wireless Access in Vehicular Environments;

              document freely available at URL

              http://standards.ieee.org/getieee802/download/802.11p-2010.pd=
f

              http://standards.ieee.org/getieee802/download/802.11p-2010.pd=
f retrieved on September 20th,

              2013.".

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-A.  ChangeLog


   The changes are listed in reverse chronological order, most recent

   changes appearing at the top of the list.

   From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03=
 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04

   o  Removed a few informative references pointing to Dx draft IEEE

      1609 documents.

   o  Removed outdated informative references to ETSI documents.

   o  Added citations to IEEE 1609.2, .3 and .4-2016.

   o  Minor textual issues.




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   From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02=
 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03

   o  Keep the previous text on multiple addresses, so remove talk about

      MIP6, NEMOv6 and MCoA.

   o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.

   o  Clarified the figure showing Infrastructure mode and OCB mode side

      by side.

   o  Added a reference to the IP Security Architecture RFC.

   o  Detailed the IPv6-per-channel prohibition paragraph which reflects

      the discussion at the last IETF IPWAVE WG meeting.

   o  Added section "Address Mapping -- Unicast".

   o  Added the ".11 Trailer" to pictures of 802.11 frames.

   o  Added text about SNAP carrying the Ethertype.

   o  New RSU definition allowing for it be both a Router and not

      necessarily a Router some times.

   o  Minor textual issues.

   From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01=
 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02

   o  Replaced almost all occurences of 802.11p with 802.11-OCB, leaving

      only when explanation of evolution was necessary.

   o  Shortened by removing parameter details from a paragraph in the

      Introduction.

   o  Moved a reference from Normative to Informative.

   o  Added text in intro clarifying there is no handover spec at IEEE,

      and that 1609.2 does provide security services.

   o  Named the contents the fields of the EthernetII header (including

      the Ethertype bitstring).

   o  Improved relationship between two paragraphs describing the

      increase of the Sequence Number in 802.11 header upon IP

     fragmentation.




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   o  Added brief clarification of "tracking".

   From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-00=
 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01

   https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01

   o  Introduced message exchange diagram illustrating differences

      between 802.11 and 802.11 in OCB mode.

   o  Introduced an appendix listing for information the set of 802.11

      messages that may be transmitted in OCB mode.

   o  Removed appendix sections "Privacy Requirements", "Authentication

      Requirements" and "Security Certificate Generation".

   o  Removed appendix section "Non IP Communications".

   o  Introductory phrase in the Security Considerations section.

   o  Improved the definition of "OCB".

   o  Introduced theoretical stacked layers about IPv6 and IEEE layers

      including EPD.

   o  Removed the appendix describing the details of prohibiting IPv6 on

      certain channels relevant to 802.11-OCB.

   o  Added a brief reference in the privacy text about a precise clause

      in IEEE 1609.3 and .4.

   o  Clarified the definition of a Road Side Unit.

   o  Removed the discussion about security of WSA (because is non-IP).

   o  Removed mentioning of the GeoNetworking discussion.

   o  Moved references to scientific articles to a separate 'overview'

      draft, and referred to it.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-B.  Changes Needed on a software driver 802.11a to become a

             802.11-OCB driver

   The 802.11p amendment modifies both the 802.11 stack's physical and

   MAC layers but all the induced modifications can be quite easily

   obtained by modifying an existing 802.11a ad-hoc stack.

   Conditions for a 802.11a hardware to be 802.11-OCB compliant:





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Internet-Draft             IPv6-over-80211ocb                August 2017


   o  The chip must support the frequency bands on which the regulator

      recommends the use of ITS communications, for example using IEEE

      802.11-OCB layer, in France: 5875MHz to 5925MHz.

   o  The chip must support the half-rate mode (the internal clock

      should be able to be divided by two).

   o  The chip transmit spectrum mask must be compliant to the "Transmit

      spectrum mask" from the IEEE 802.11p amendment (but experimental

      environments tolerate otherwise).

   o  The chip should be able to transmit up to 44.8 dBm when used by

      the US government in the United States, and up to 33 dBm in

      Europe; other regional conditions apply.

   Changes needed on the network stack in OCB mode:

   o  Physical layer:

      *  The chip must use the Orthogonal Frequency Multiple Access

         (OFDM) encoding mode.

      *  The chip must be set in half-mode rate mode (the internal clock

         frequency is divided by two).

      *  The chip must use dedicated channels and should allow the use

         of higher emission powers.  This may require modifications to

         the regulatory domains rules, if used by the kernel to enforce

         local specific restrictions.  Such modifications must respect

         the location-specific laws.

      MAC layer:

      *  All management frames (beacons, join, leave, and others)

         emission and reception must be disabled except for frames of

         subtype Action and Timing Advertisement (defined below).

      *  No encryption key or method must be used.

      *  Packet emission and reception must be performed as in ad-hoc

         mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).

      *  The functions related to joining a BSS (Association Request/

         Response) and for authentication (Authentication Request/Reply,

         Challenge) are not called.

      *  The beacon interval is always set to 0 (zero).




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Internet-Draft             IPv6-over-80211ocb                August 2017


      *  Timing Advertisement frames, defined in the amendment, should

         be supported.  The upper layer should be able to trigger such

         frames emission and to retrieve information contained in

         received Timing Advertisements.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.  Design Considerations


   The networks defined by 802.11-OCB are in many ways similar to other

   networks of the 802.11 family.  In theory, the encapsulation of IPv6

   over 802.11-OCB could be very similar to the operation of IPv6 over

   other networks of the 802.11 family.  However, the high mobility,

   strong link asymetry and very short connection makes the 802.11-OCB

   link significantly different from other 802.11 networks.  Also, the

   automotive applications have specific requirements for reliability,

   security and privacy, which further add to the particularity of the

   802.11-OCB link.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.1.  Vehicle ID


   Automotive networks require the unique representation of each of

   their node.  Accordingly, a vehicle must be identified by at least

   one unique identifier.  The current specification at ETSI and at IEEE

   1609 identifies a vehicle by its MAC address uniquely obtained from

   the 802.11-OCB NIC.

   A MAC address uniquely obtained from a IEEE 802.11-OCB NIC

   implicitely generates multiple vehicle IDs in case of multiple

   802.11-OCB NICs.  A mechanims to uniquely identify a vehicle

   irrespectively to the different NICs and/or technologies is required.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.2.  Reliability Requirements


   The dynamically changing topology, short connectivity, mobile

   transmitter and receivers, different antenna heights, and many-to-

   many communication types, make IEEE 802.11-OCB links significantly

   different from other IEEE 802.11 links.  Any IPv6 mechanism operating

   on IEEE 802.11-OCB link MUST support strong link asymetry, spatio-

   temporal link quality, fast address resolution and transmission.

   IEEE 802.11-OCB strongly differs from other 802.11 systems to operate

   outside of the context of a Basic Service Set.  This means in

   practice that IEEE 802.11-OCB does not rely on a Base Station for all

   Basic Service Set management.  In particular, IEEE 802.11-OCB SHALL

   NOT use beacons.  Any IPv6 mechanism requiring L2 services from IEEE

   802.11 beacons MUST support an alternative service.






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Internet-Draft             IPv6-over-80211ocb                August 2017


   Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST

   implement a mechanism for transmitter and receiver to converge to a

   common channel.

   Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST

   implement an distributed mechanism to authenticate transmitters and

   receivers without the support of a DHCP server.

   Time synchronization not being available, IPv6 over IEEE 802.11-OCB

   MUST implement a higher layer mechanism for time synchronization

   between transmitters and receivers without the support of a NTP

   server.

   The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB

   MUST disable management mechanisms requesting acknowledgements or

   replies.

   The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE

   802.11-OCB MUST implement fast IPv6 mobility management mechanisms.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.3.  Multiple interfaces


   There are considerations for 2 or more IEEE 802.11-OCB interface

   cards per vehicle.  For each vehicle taking part in road traffic, one

   IEEE 802.11-OCB interface card could be fully allocated for Non IP

   safety-critical communication.  Any other IEEE 802.11-OCB may be used

   for other type of traffic.

   The mode of operation of these other wireless interfaces is not

   clearly defined yet.  One possibility is to consider each card as an

   independent network interface, with a specific MAC Address and a set

   of IPv6 addresses.  Another possibility is to consider the set of

   these wireless interfaces as a single network interface (not

   including the IEEE 802.11-OCB interface used by Non IP safety

   critical communications).  This will require specific logic to

   ensure, for example, that packets meant for a vehicle in front are

   actually sent by the radio in the front, or that multiple copies of

   the same packet received by multiple interfaces are treated as a

   single packet.  Treating each wireless interface as a separate

   network interface pushes such issues to the application layer.

   The privacy requirements of [] imply that if these multiple

   interfaces are represented by many network interface, a single

   renumbering event SHALL cause renumbering of all these interfaces.

   If one MAC changed and another stayed constant, external observers

   would be able to correlate old and new values, and the privacy

   benefits of randomization would be lost.




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Internet-Draft             IPv6-over-80211ocb                August 2017


   The privacy requirements of Non IP safety-critical communications

   imply that if a change of pseudonyme occurs, renumbering of all other

   interfaces SHALL also occur.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.4.  MAC Address Generation


   When designing the IPv6 over 802.11-OCB address mapping, we will

   assume that the MAC Addresses will change during well defined

   "renumbering events".  The 48 bits randomized MAC addresses will have

   the following characteristics:

   o  Bit "Local/Global" set to "locally admninistered".

   o  Bit "Unicast/Multicast" set to "Unicast".

   o  46 remaining bits set to a random value, using a random number

      generator that meets the requirements of [https://tools.ietf.org/html=
/rfc4086].

   The way to meet the randomization requirements is to retain 46 bits

   from the output of a strong hash function, such as SHA256, taking as

   input a 256 bit local secret, the "nominal" MAC Address of the

   interface, and a representation of the date and time of the

   renumbering event.

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-D.  IEEE 802.11 Messages Transmitted in OCB mode


   For information, at the time of writing, this is the list of IEEE

   802.11 messages that may be transmitted in OCB mode, i.e. when

   dot11OCBActivated is true in a STA:

   o  The STA may send management frames of subtype Action and, if the

      STA maintains a TSF Timer, subtype Timing Advertisement;

   o  The STA may send control frames, except those of subtype PS-Poll,

      CF-End, and CF-End plus CFAck;

   o  The STA may send data frames of subtype Data, Null, QoS Data, and

      QoS Null.

Authors' Addresses

--_000_D5CA344D22C206sgundaveciscocom_
Content-Type: text/html; charset="Windows-1252"
Content-ID: <27E9639D378CB945B2D3DD7E8628CA4C@emea.cisco.com>
Content-Transfer-Encoding: quoted-printable







Hi Francois,







Thanks you for your response and also for clarification on the QoS asp=
ects which are present in OCB. Hopefully, you can address these comments an=
d my other comments in the next rev.






















Regards


Sri



















From: Fran=E7ois Simon <gsgsimon@gmail.com>

Date: Monday, August 28, 2017 at 11=
:08 AM

To: Sri Gundavelli <sgundave@cisco.com>

Cc: "its@ietf.org" <its@ietf.=
org>, "fygsimon@gmail.com=
" <fygsimon@gmail.com=
>

Subject: RE: [ipwave] Review commen=
ts on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt











RE: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb=
-04.txt



Mr. Gundaveli,


I provided some =
comments and responses in the text below your comments identified by=
=93[Fygs]
 and =93bold=94.


If you have addi=
tional questions, please, let me know.


Sincerely,




Francois Simon


From: its [mailto:its-bounces@ietf.org] On Beha=
lf Of Sri Gundavelli (sgundave)


Sent: Sunday, Au=
gust 27, 2017 11:01 PM


To: 
its@ietf.org


Subject: [ipwave=
] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt




Attached is my r=
eview feedback. 


In general there=
 is lot of good information in the document. But, there are also few areas =
where additional clarifications will greatly help.


1.) Its not clea=
r, if the document makes any assumption on the operating environment/commun=
ication profile. There is not much discussion on that aspect; For example, =
Is it always a one-hop communication between
 RSU and OBU where the 802.11-OCB link?  So, is the use of IPv6 only i=
n that context of 1-hop communication? 


2.) There is als=
o no discussion on how these links get formed in vehicular environment and =
when they are attached/detached. 


3.) How do nodes=
 discover each other?  How does ND resolution work? Are these messages=
 received by a multiple RSU=92s, or a single RSU? Whats the implication of =
that. Note that you don=92t have that issue in
 802.11, given the association to an access point, which in turn maps the l=
inks to a VLAN/subnet.


4.) What happens=
 as a vehicle moves between RSU=92s, how does it impact address configurati=
on?   Is DHCPv6 based address configuration relevant here?




 Please see=
 inline for additional comments.






----------------=
--------------------------------------------------


 


Transmission of =
IPv6 Packets over IEEE 802.11 Networks in mode Outside


  &nbs=
p;     


the Context of a=
 Basic Service Set (IPv6-over-80211ocb)


  &nbs=
p;           


draft-ietf-ipwav=
e-ipv6-over-80211ocb-04.txt






[Sri] May be cha=
nge to, =93..in mode .." =97> =93..operating in mode ..=94  ?<=
/font>


[Fygs] Agreed




Abstract<=
/span>


   In =
order to transmit IPv6 packets on IEEE 802.11 networks run outside


   the=
 context of a basic service set (OCB, earlier "802.11p") there is=



   a n=
eed to define a few parameters such as the recommended Maximum


   Tra=
nsmission Unit size, the header format preceding the IPv6 header,


   the=
 Type value within it, and others.  This document describes these


   par=
ameters for IPv6 and IEEE 802.11 OCB networks; it portrays the


   lay=
ering of IPv6 on 802.11 OCB similarly to other known 802.11 and


   Eth=
ernet layers - by using an Ethernet Adaptation Layer.


[Sri] Is it =93r=
ecommended MTU size", or "supported MTU size on the 802.11 OCB li=
nk? 





   In =
addition, the document attempts to list what is different in<=
/p>

   802=
.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n


   lay=
ers, layers over which IPv6 protocols operates without issues.


   Mos=
t notably, the operation outside the context of a BSS (OCB) has


   imp=
act on IPv6 handover behaviour and on IPv6 security.


[Sri] Minor comm=
ent. May be instead of using the =93layer=94 terminology, you may want to p=
resent this as IPv6 support on "802.11 OCB" links.<=
/p>

[Fygs] 802.11=
 OCB provides data link and PHY services to IPv6


 


   An =
example of an IPv6 packet captured while transmitted over an IEEE


   802=
.11 OCB link (802.11p) is given.


[Sri] Last parag=
raph can be ommitted in my view. That=92s too much of detail for Abstract.<=
/font>


[Fygs] - Agre=
e




Status of This M=
emo


   Thi=
s Internet-Draft is submitted in full conformance with the

   pro=
visions of 
https://tools.ietf.org/html/bcp78 and 
https://tools.ietf.org/html/bcp79.


   Int=
ernet-Drafts are working documents of the Internet Engineering


   Tas=
k Force (IETF).  Note that other groups may also distribute






Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 1]


________________=
________________________


http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-2<=
/font>


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   wor=
king documents as Internet-Drafts.  The list of current Internet-


   Dra=
fts is at 
http://datatracker.ietf.org/drafts/current/.


   Int=
ernet-Drafts are draft documents valid for a maximum of six months


   and=
 may be updated, replaced, or obsoleted by other documents at any


   tim=
e.  It is inappropriate to use Internet-Drafts as reference


   mat=
erial or to cite them other than as "work in progress."


   Thi=
s Internet-Draft will expire on February 18, 2018.


Copyright Notice=



   Cop=
yright (c) 2017 IETF Trust and the persons identified as the<=
/p>

   doc=
ument authors.  All rights reserved.


   Thi=
s document is subject to
https://tools.ietf.org/html/b=
cp78 and the IETF Trust's Legal


   Pro=
visions Relating to IETF Documents


   (http://trustee.ietf.org/lice=
nse-info) in effect on the date of


   pub=
lication of this document.  Please review these documents


   car=
efully, as they describe your rights and restrictions with respect


   to =
this document.  Code Components extracted from this document must


   inc=
lude Simplified BSD License text as described in Section 4.e of


   the=
 Trust Legal Provisions and are provided without warranty as<=
/p>

   des=
cribed in the Simplified BSD License.


Table of Content=
s


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-1.  Introduction  . . . . . . . . . . . . . . . . . . . . . =
. . .  

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-3<=
/a>


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .=
  

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-5<=
/a>


   3.&=
nbsp; Communication Scenarios where IEEE 802.11 OCB Links are Used &nb=
sp;  6


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-4.  Aspects introduced by the OCB mode to 802.11  . . . . . =
. . .  

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-6<=
/a>


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.  Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . .=
 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-10=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.1.  Maximum Transmission Unit (MTU) . . . . . . . . . . . . .&n=
bsp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-10=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.2. =
Frame Format  . . . . . . . . . . . . . . . . .=
 . . . . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-11=



   &=
nbsp;   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.2.1.  Ethernet Adaptation Layer . . . . . . . . . . . . . .&nbs=
p;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-12=



   &=
nbsp; 
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.3. Li=
nk-Local Addresses  . . . . . . . . . . . . . . . . . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-13=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.4.  Address Mapping . . . . . . . . . . . . . . . . . . . . .&n=
bsp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14=



  &nbs=
p;    
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.4.1.  Address Mapping -- Unicast  . . . . . . . . . . . . =
. 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14=



  &nbs=
p;    
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.4.2.  Address Mapping -- Multicast  . . . . . . . . . . . =
. 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.5.  Stateless Autoconfiguration . . . . . . . . . . . . . . .&n=
bsp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-15=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.6. =
Subnet Structure  . . . . . . . . . . . . . . .=
 . . . . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-16=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-6. Exam=
ple IPv6 Packet captured over a IEEE 802.11-OCB link  . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-16=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-6.1.  Capture in Monitor Mode . . . . . . . . . . . . . . . . .&n=
bsp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-17=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-6.2.  Capture in Normal Mode  . . . . . . . . . . . . . . . =
. . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-19=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-7.  Security Considerations . . . . . . . . . . . . . . . . . . .=
 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-21=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .=
 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-9.  Contributors  . . . . . . . . . . . . . . . . . . . . . =
. . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .=
 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22=







Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 2]


________________=
________________________


http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-3<=
/font>


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-11. References  . . . . . . . . . . . . . . . . . . . . . . . . .=
 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-23=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-11.1.  Normative References . . . . . . . . . . . . . . . . . .&n=
bsp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-23=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-11.2.  Informative References . . . . . . . . . . . . . . . . .&n=
bsp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-24=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-A.  ChangeLog  . . . . . . . . . . . . . . . . . . . . .&nb=
sp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-26=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-B.  Changes Needed on a software driver 802.11a to=



  &nbs=
p;             =
become a           &=
nbsp;         802.11-OCB driver . .=
 . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-28=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.  Design Considerations  . . . . . . . . . . . . . . .&nb=
sp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.1.  Vehicle ID  . . . . . . . . . . . . . . . . . . . . .=
 . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.2.  Reliability Requirements  . . . . . . . . . . . . . .=
 . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.3.  Multiple interfaces . . . . . . . . . . . . . . . . . . .&=
nbsp;

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-31=



  &nbs=
p;  
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.4.  MAC Address Generation  . . . . . . . . . . . . . . .=
 . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32=



   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-D.  IEEE 802.11 Messages Transmitted in OCB mode . . . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32=



   Aut=
hors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32=



h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
1.  Introduction




   Thi=
s document describes the transmission of IPv6 packets on IEEE Std


   802=
.11 OCB networks (earlier known as 802.11p).  


[Sri] Please add=
 a reference to the IEEE specification that defines the OCB mode.



[Fygs] Since =
2010 the OCB is defined in IEEE Std 802.11p, IEEE Std 802.11-2012, and IEEE=
 802.11-2016.




This involves th=
e


   lay=
ering of IPv6 networking on top of the IEEE 802.11 MAC layer (with


   an =
LLC layer).  Compared to running IPv6 over the Ethernet MAC layer,


   the=
re is no modification required to the standards: IPv6 works fine


   dir=
ectly over 802.11 OCB too (with an LLC layer).


   The=
 term "802.11p" is an earlier definition.  As of year 2012, =
the


   beh=
aviour of "802.11p" networks has been rolled in the document IEEE=



   Std=
 802.11-2012.  In this document the term 802.11p disappears.


   Ins=
tead, each 802.11p feature is conditioned by a flag in the

   Man=
agement Information Base.  That flag is named "OCBActivated"=
.


   Whe=
never OCBActivated is set to true the feature it relates to

   rep=
resents an earlier 802.11p feature.  For example, an 802.11


   STA=
tion operating outside the context of a basic service set has the


   OCB=
Activated flag set.  Such a station, when it has the flag set, it


   use=
s a BSS identifier equal to ff:ff:ff:ff:ff:ff.


   In =
the following text we use the term "802.11p" to mean 802.11-2012<=
/font>


   OCB=
.


   The=
 IPv6 network layer operates on 802.11 OCB in the same manner as


   it =
operates on 802.11 WiFi, with a few particular exceptions.  The=



   IPv=
6 network layer operates on WiFi by involving an Ethernet


   Ada=
ptation Layer; this Ethernet Adaptation Layer maps 802.11 headers


   to =
Ethernet II headers.  The operation of IP on Ethernet is described


   in =
[https://tools.ietf.org/htm=
l/rfc1042] and [https:/=
/tools.ietf.org/html/rfc2464].  The situation of
 IPv6 networking layer


   on =
Ethernet Adaptation Layer is illustrated below:














Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 3]


________________=
________________________


http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-4<=
/font>


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




  &nbs=
p;            &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp; |           &n=
bsp;     IPv6       =
           |


  &nbs=
p;            &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp; |       Ethernet Adaptation Layer =
      |


  &nbs=
p;            &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp; |           &n=
bsp; 802.11 WiFi MAC         &=
nbsp; |


  &nbs=
p;            &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp; |           &n=
bsp; 802.11 WiFi PHY         &=
nbsp; |


  &nbs=
p;            &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+




   (in=
 the above figure, a WiFi profile is represented; this is used


   als=
o for OCB profile.)


   A m=
ore theoretical and detailed view of layer stacking, and


   int=
erfaces between the IP layer and 802.11 OCB layers, is illustrated


   bel=
ow.  The IP layer operates on top of the EtherType Protocol


   Dis=
crimination (EPD); this Discrimination layer is described in IEEE


   Std=
 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP


   (Li=
nk Layer Control Service Accesss Point).




  &nbs=
p;        +-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+


  &nbs=
p;        |     =
;            IPv6&nb=
sp;            =
     |


  &nbs=
p;        +-+-+-+-+-=
+-{            }=
+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;       {   LLC_SAP  }&nbs=
p;            &=
nbsp;   802.11 OCB


  &nbs=
p;        +-+-+-+-+-=
+-{            }=
+-+-+-+-+-+-+-+  Boundary


  &nbs=
p;        |     =
;       EPD     &nbs=
p;    |       |  &nb=
sp;  |


  &nbs=
p;        |     =
;            &n=
bsp;       | MLME  |   &n=
bsp; |


  &nbs=
p;        +-+-+-{  MAC_=
SAP   }+-+-+-|  MLME_SAP   |


  &nbs=
p;        |     =
; MAC Sublayer       |    =
;   |     |  802.11 OCB

  &nbs=
p;        |     and =
ch. coord.      |     &nb=
sp; | SME |  Services


  &nbs=
p;        +-+-+-{  =
; PHY_SAP  }+-+-+-+-+-+-+-|  &nb=
sp;  |


  &nbs=
p;        |     =
;            &n=
bsp;       | PLME  |   &n=
bsp; |


  &nbs=
p;        |     =
;       PHY Layer    | &n=
bsp; PLME_SAP  |


  &nbs=
p;        +-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+




   In =
addition to the description of interface between IP and MAC using


   &qu=
ot;Ethernet Adaptation Layer" and "Ethernet Protocol Discriminati=
on


   (EP=
D)" it is worth mentioning that SNAP [https://tools.ietf.org/html/rfc1042] is used to carry


   the=
 IPv6 Ethertype.


   How=
ever, there may be some deployment considerations helping optimize


   the=
 performances of running IPv6 over 802.11-OCB (e.g. in the case of


   han=
dovers between 802.11 OCB-enabled access routers, or the


   con=
sideration of using the IP security layer [https://tools.ietf.org/html/rfc4301]).







Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 4]


________________=
________________________


http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-5<=
/font>


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   The=
re are currently no specifications for handover between OCB links


   sin=
ce these are currently specified as LLC-1 links (i.e.


   con=
nectionless).  Any handovers must be performed above the Data Link


   Lay=
er.  Also, while there is no encryption applied below the network


   lay=
er using 802.11p, 1609.2 [https://tools.ietf.org/html/d=
raft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee1609.2]
 does provide security


   ser=
vices for applications to use so that there can easily be data


   sec=
urity over the air without invoking IPsec.


   We =
briefly introduce the vehicular communication scenarios where IEEE


   802=
.11-OCB links are used. 


[Sri] I have not=
 seen much discussion on the link / communication assumptions.



[Fygs] Not su=
re of what is meant by assumptions in this context.




 This is fo=
llowed by a description of


   dif=
ferences in specification terms, between 802.11 OCB and


   802=
.11a/b/g/n (and the same differences expressed in terms of

   req=
uirements to software implementation are listed in

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-B.)


   The=
 document then concentrates on the parameters of layering IP over


   802=
.11 OCB as over Ethernet: value of MTU, the contents of Frame=



   For=
mat, the rules for forming Interface Identifiers, the mechanism


   for=
 Address Mapping and for State-less Address Auto-configuration.


   The=
se are precisely the same as IPv6 over Ethernet [https://tools.ietf.org/html/rfc2464].


   As =
an example, these characteristics of layering IPv6 straight over


   LLC=
 over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet


   cap=
tured over a 802.11 OCB link; this is described in the section


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-6.


   A c=
ouple of points can be considered as different, although they are


   not=
 required in order to have a working implementation of IPv6-over-


   802=
.11-OCB.  These points are consequences of the OCB operation which


   is =
particular to 802.11 OCB (Outside the Context of a BSS).  First,


   the=
 handovers between OCB links need specific behaviour for IP Router


   Adv=
ertisements, or otherwise 802.11 OCB's Time Advertisement, or of


   hig=
her layer messages such as the 'Basic Safety Message' (in the US)


   or =
the 'Cooperative Awareness Message' (in the EU) or the 'WAVE<=
/p>

   Rou=
ting Advertisement'; second, the IP security mechanisms are

   nec=
essary, since OCB means that 802.11 is stripped of all 802.11=



   lin=
k-layer security; a small additional security aspect which is=



   sha=
red between 802.11 OCB and other 802.11 links is the privacy<=
/p>

   con=
cerns related to the address formation mechanisms.


   In =
the published literature, many documents describe aspects related


   to =
running IPv6 over 802.11 OCB:


   [https://tools.ietf.org/=
html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.jeong-ipwave-vehicular=
-networking-survey].


h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
2.  Terminology




   The=
 key words "MUST", "MUST NOT", "REQUIRED", &q=
uot;SHALL", "SHALL NOT",


   &qu=
ot;SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY=
", and "OPTIONAL" in this


   doc=
ument are to be interpreted as described in
https://tools.ietf.org/html=
/rfc2119 [https://tools=
.ietf.org/html/rfc2119].






Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 5]


________________=
________________________


http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-6<=
/font>


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   RSU=
: Road Side Unit.  A computer equipped with at least one IEEE


   802=
.11 interface operated in OCB mode.  This definition applies to=



   thi=
s document.  An RSU may be connected to the Internet, and may be


   equ=
ipped with additional wired or wireless network interfaces running


   IP.=
  An RSU MAY be an IP Router.




[Sri] RSU can be=
 compared to an 802.11 access point; Or, WTP as defined in CAPWAP specifica=
tion, RFC5415.


[Fygs] While =
I am not familiar with =93WTP as defined in CAPWAP specification, RFC5415=
=94, I know that an RSU has no commonality with an 802.11 AP.




Perhaps. rephras=
e as below?:


"RSU: Road =
Side Unit. Its a wireless termination point (WTP), as defined in RFC5415 wi=
th one key difference, where the wireless physical and the mac layer is MAC=
 layers configured to operate in 802.11 OCB
 mode.  The RSU communicates with the On board Unit (OBU) in the vehic=
le over 802.11 wireless link operating in OCB mode.=94



[Fygs]: =
 This seems reasonable and accurate.  This would be for V2I mode.




** Also, since y=
ou are defining the RSU term, should you also not define OBU (On board Unit=
) in the vehicle which is the entity on the other end of the link? =93RSU -=
---802.11-OCB=97=97OBU=94 ? May be introduce the
 OCB definition separately, just as you did with RSU, and show the communic=
ation link as 802.11-OCB.


[Fygs] Here i=
s a definition of OBU (FCC): =93An On-Board Unit is a DSRCS transceiver tha=
t is normally mounted in or on a vehicle, or which in some instances may be=
 a portable unit. An OBU can be operational
 while a vehicle or person is either mobile or stationary.=94




   OCB=
: outside the context of a basic service set (BSS): A mode of=



   ope=
ration in which a STA is not a member of a BSS and does not

   uti=
lize IEEE Std 802.11 authentication, association, or data


   con=
fidentiality.


   802=
.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is


   fla=
gged by "dot11OCBActivated".  This means: IEEE 802.11e for q=
uality


   of =
service; 802.11j-2004 for half-clocked operations; and (what was


   kno=
wn earlier as) 802.11p for operation in the 5.9 GHz band and in


   mod=
e OCB.




[Sri] The text s=
tarting with. =93This means=94 is not clear to me. Does it 802.11e is suppo=
rted with 802.11OCB mode. Please clarify=



[Fygs]=
QoS is required f=
or 802.11 OCB.




h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
3.  Communication Scenarios where IEEE
 802.11 OCB Links are Used




   The=
 IEEE 802.11 OCB Networks are used for vehicular communications,


   as =
'Wireless Access in Vehicular Environments'.  The IP communication


   sce=
narios for these environments have been described in several<=
/p>

   doc=
uments, among which we refer the reader to one recently updated


   [https://tools.ietf.org/html/draft-ie=
tf-ipwave-ipv6-over-80211ocb-04#ref-I-D.petrescu-its-scenarios-reqs],
 about scenarios and requirements


   for=
 IP in Intelligent Transportation Systems.




[Sri] You can do=
 bit more justice to this section. 


Explain the link=
 model.  =93STA ----802.11-OCB=97=97STA=94. Then talk about the applic=
ability in Vehicular networks, with STA's as RSU and OCB.


You may also wan=
t to talk about, how links get formed/terminated; how nodes peer/discover a=
nd how mobility works ..etc.  While 802.11-OCB is clearly specified an=
d the use of IPv6 over such link is also not
 radically new, but the operating environment which is vehicular brings man=
y new things. That description is not present any where.


h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
4.  Aspects introduced by the OCB mode
 to 802.11




   In =
the IEEE 802.11 OCB mode, all nodes in the wireless range can=



   dir=
ectly communicate with each other without authentication/


   ass=
ociation procedures.  Briefly, the IEEE 802.11 OCB mode has the=



   fol=
lowing properties:




[Sri] Can you ad=
d some text on how nodes (ST1 and STA2) discover each other on such links s=
upporting 802.11 OCB mode.


   o&n=
bsp; The use by each node of a 'wildcard' BSSID (i.e., each bit of the


  &nbs=
p;   BSSID is set to 1)


   o&n=
bsp; No IEEE 802.11 Beacon frames transmitted


   o&n=
bsp; No authentication required


   o&n=
bsp; No association needed


o  =
;    No encryption provided




[Fygs] All th=
e nodes in the communication range (OBU and RSU) receivesall
the messages transmitted (OBU and RSU) within the communications range. =
The conflicts
 are resolved by the MAC CDMA function.  





[Sri] Can you cl=
arify what you mean when you say =93No xxx required=94 / =93No xxx needed=
=94  for the above capabilities.  What does =93needed=94 or =93re=
quired=94 mean?  Does it mean, =93Authentication", =93Association=
" and
 =93Encryption=94 is optional on this link, or that its not supported on 80=
2.11 OCB links.


[Fygs]The original text in IEEE 802.11p specifies:



=93=
Change
 the lettered list items (a) through (c) of 5.3.1 as follows:


<=
/b>a) Authe=
ntication (not used when dot11OCBEnabled is true)


b) =
Deauthentication (not used when dot11OCBEnabled is true)<=
/p>

c) Data confidentiality (not used when dot11OCBEnabled =
is true)=94 



   o&n=
bsp; Flag dot11OCBActivated set to true


   The=
 following message exchange diagram illustrates a comparison<=
/p>

   bet=
ween traditional 802.11 and 802.11 in OCB mode.  The 'Data'






Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 6]


________________=
________________________


http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-7<=
/font>


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   mes=
sages can be IP messages such as the messages used in Stateless or


   Sta=
teful Address Auto-Configuration, or other IP messages.  




[Sri] Lets separ=
ate the discussion on IP Address configuration using SLAAC/DHCP on such lin=
ks from the above description. The Data packets here can be application pac=
kets such as HTTP or other packets. May
 be additional discussion is needed on the IP address configuration on 802.=
11-OCB links.





Other


   802=
.11 management and control frames (non IP) may be transmitted, as


   spe=
cified in the 802.11 standard.  For information, the names of


   the=
se messages as currently specified by the 802.11 standard are=



   lis=
ted in 
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-D.












  &nbs=
p;  STA          &nb=
sp;         AP   &nb=
sp;          STA1  &=
nbsp;           &nbs=
p;    STA2


  &nbs=
p;  |           =
;           |  =
             |&=
nbsp;           &nbs=
p;         |


  &nbs=
p;  |<------ Beacon -------|      &nb=
sp;        |<------ Data -------->=
|


  &nbs=
p;  |           =
;           |  =
             |&=
nbsp;           &nbs=
p;         |


  &nbs=
p;  |---- Probe Req. ----->|      &nb=
sp;        |<------ Data -------->=
|


  &nbs=
p;  |<--- Probe Res. ------|      &nb=
sp;        |    &nbs=
p;            &=
nbsp;    |


  &nbs=
p;  |           =
;           |  =
             |&=
lt;------ Data -------->|


  &nbs=
p;  |---- Auth Req. ------>|      &nb=
sp;        |    &nbs=
p;            &=
nbsp;    |


  &nbs=
p;  |<--- Auth Res. -------|      &nb=
sp;        |<------ Data -------->=
|


  &nbs=
p;  |           =
;           |  =
             |&=
nbsp;           &nbs=
p;         |


  &nbs=
p;  |---- Asso Req. ------>|      &nb=
sp;        |<------ Data -------->=
|


  &nbs=
p;  |<--- Asso Res. -------|      &nb=
sp;        |    &nbs=
p;            &=
nbsp;    |


  &nbs=
p;  |           =
;           |  =
             |&=
lt;------ Data -------->|


  &nbs=
p;  |<------ Data -------->|      =
         |    &=
nbsp;           &nbs=
p;     |


  &nbs=
p;  |<------ Data -------->|      =
         |<------ Data --------&=
gt;|


  &nbs=
p; (a) 802.11 Infrastructure mode       =
  (b) 802.11 OCB mode




   The=
 link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010=



   [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-=
over-80211ocb-04#ref-ieee802.11p-2010] as an amendment
 to IEEE Std 802.11 (TM) -2007,


   tit=
led "Amendment 6: Wireless Access in Vehicular Environments".


   Sin=
ce then, this amendment has been included in IEEE 802.11(TM)-2012


   [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-o=
ver-80211ocb-04#ref-ieee802.11-2012], titled "IEEE
 Standard for Information technology--


   Tel=
ecommunications and information exchange between systems Local and


   met=
ropolitan area networks--Specific requirements Part 11: Wireless


   LAN=
 Medium Access Control (MAC) and Physical Layer (PHY)


   Spe=
cifications"; the modifications are diffused throughout various=



   sec=
tions (e.g. the Time Advertisement message described in the

   ear=
lier 802.11 (TM) p amendment is now described in section 'Frame


   for=
mats', and the operation outside the context of a BSS described in


   sec=
tion 'MLME').


   In =
document 802.11-2012, specifically anything referring


   &qu=
ot;OCBActivated", or "outside the context of a basic service set&=
quot; is


   act=
ually referring to the 802.11p aspects introduced to 802.11.  Note


   tha=
t in earlier 802.11p documents the term "OCBEnabled" was used


   ins=
tead of te current "OCBActivated".










Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 7]


________________=
________________________


http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-8<=
/font>


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   In =
order to delineate the aspects introduced by 802.11 OCB to 802.11,


   we =
refer to the earlier [https://tools.ietf.org/html=
/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee802.11p-2010]. 
 The amendment is


   con=
cerned with vehicular communications, where the wireless link is


   sim=
ilar to that of Wireless LAN (using a PHY layer specified by<=
/p>

   802=
.11a/b/g/n), but which needs to cope with the high mobility factor


   inh=
erent in scenarios of communications between moving vehicles, and


   bet=
ween vehicles and fixed infrastructure deployed along roads.<=
/p>

   Whi=
le 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is

   con=
cerned more with MAC modifications, and a little with PHY


   mod=
ifications; the others are mainly about PHY modifications.  It is


   pos=
sible in practice to combine a 'p' MAC with an 'a' PHY by


   ope=
rating outside the context of a BSS with OFDM at 5.4GHz.


   The=
 802.11 OCB links are specified to be compatible as much as

   pos=
sible with the behaviour of 802.11a/b/g/n and future generation


   IEE=
E WLAN links.  From the IP perspective, an 802.11 OCB MAC layer=



   off=
ers practically the same interface to IP as the WiFi and Ethernet


   lay=
ers do (802.11a/b/g/n and 802.3).




[Sri] A packet s=
ent from a vehicle=92s OBU is received by a single RSU, or multiple RSU=92s=
? How does the link-layer resolution happen?


[Fygs] Assumi=
ng that:


a)  =
;   If there aresingle
 or multip=
le RSUsin
 the communication range and it is a=
multicast<=
b> message=
,the
 single RSU or RSUs in the comm. range will receive it (eventually).
 There is no resolution at the link layer. The RSU(s<=
font face=3D"Calibri">)
 will determine their 
=93interes=
t=94 based=
 on the co=
ntent of the message at the higher layers (application);<=
span lang=3D"en-us">


b)  =
;   If there are single or multiple RSUs in the communication r=
and and it isunicast
 message, then the link-layer resolves by thedestination
MAC address.


    

    





   To =
support this similarity statement (IPv6 is layered on top of LLC


   on =
top of 802.11 OCB similarly as on top of LLC on top of


   802=
.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to


   ana=
lyze the differences between 802.11 OCB and 802.11 specifications.


   Whe=
reas the 802.11p amendment specifies relatively complex and

   num=
erous changes to the MAC layer (and very little to the PHY layer),


   we =
note there are only a few characteristics which may be important


   for=
 an implementation transmitting IPv6 packets on 802.11 OCB links.


   In =
the list below, the only 802.11 OCB fundamental points which<=
/p>

   inf=
luence IPv6 are the OCB operation and the 12Mbit/s maximum which


   may=
 be afforded by the IPv6 applications.




[Sri] I am reall=
y not sure how link throughput (12Mbps) relates to "IPv6 support on OC=
B links".


<=
/b>[Fygs] First of al=
l there is guarantee of 12 Mbps throughput because of collisions and other =
interferences, 12 Mbps data rate was probably
 intended.


<=
/b>The data rates<=
span lang=3D"en-us">
 for 20 MHz channel spacingare6,
 9, 12, 18, 24, 36,48,
 and 54 Mb/s wi=
th mandatory support of 6, 12, and 24 Mbps;


Data rates fo=
r 10 MHz channel spacing are<=
/span>3, 4.5, 6, 9, 12, 18, 24, and 27
 Mb/s.with mand=
atory support of 
 3, 6, and 12 Mb/s.




   o&n=
bsp; Operation Outside the Context of a BSS (OCB): the (earlier


  &nbs=
p;   802.11p) 802.11-OCB links are operated without a Basic Servi=
ce Set


  &nbs=
p;   (BSS).  This means that the frames IEEE 802.11 Beacon, =
Association


  &nbs=
p;   Request/Response, Authentication Request/Response, and simil=
ar,


  &nbs=
p;   are not used.  The used identifier of BSS (BSSID) has a=



  &nbs=
p;   hexadecimal value always 0xffffffffffff (48 '1' bits, repres=
ented


  &nbs=
p;   as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard=
'


  &nbs=
p;   BSSID), as opposed to an arbitrary BSSID value set by=



  &nbs=
p;   administrator (e.g.  'My-Home-AccessPoint').  The =
OCB operation -


  &nbs=
p;   namely the lack of beacon-based scanning and lack of<=
/span>


  &nbs=
p;   authentication - has a potentially strong impact on the use =
of the


  &nbs=
p;   Mobile IPv6 protocol [https://tools.ietf.org/html/rfc6275] and on the protocols for=
 IP layer


  &nbs=
p;   security [ht=
tps://tools.ietf.org/html/rfc4301].




[Sri] The docume=
nt till now has been arguing heavily on how IPv6 operates so naturally on t=
hese links and now I see discussion on =93Impact to a high-level protocol s=
uch as MIPv6=94. You may want to fix the earlier
 text. In any case,  the absence of link-layer security practically im=
pacts every application, not just MIPv6.  Also, MIPv6 does not make an=
y assumptions on the link-layer security.  Also, the the 0xFF-FF-FF-FF=
-FF-FF as the BSSID, makes the messages readable
 by all other RSU=92s in proximity. I think the discussion on the nature of=
 the link, who all see=92s the messages.. how L2 addresses are resolved is =
not explained clearly.







   o&n=
bsp; Timing Advertisement: is a new message defined in 802.11-OCB,


  &nbs=
p;   which does not exist in 802.11a/b/g/n.  This message is=
 used by






Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 8]


________________=
________________________


http=
s://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-9<=
/font>


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




  &nbs=
p;   stations to inform other stations about the value of time.&n=
bsp; It is


  &nbs=
p;   similar to the time as delivered by a GNSS system (Galileo, =
GPS,


  &nbs=
p;   ...) or by a cellular system.  This message is optional=
 for


  &nbs=
p;   implementation.  At the date of writing, an experienced=
 reviewer


  &nbs=
p;   considers that currently no field testing has used this mess=
age.


  &nbs=
p;   Another implementor considers this feature implemented in an=



  &nbs=
p;   initial manner.  In the future, it is speculated that t=
his message


  &nbs=
p;   may be useful for very simple devices which may not have the=
ir own


  &nbs=
p;   hardware source of time (Galileo, GPS, cellular network), or=
 by


  &nbs=
p;   vehicular devices situated in areas not covered by such netw=
ork


  &nbs=
p;   (in tunnels, underground, outdoors but shaded by foliage or<=
/font>


  &nbs=
p;   buildings, in remote areas, etc.)




[Sri] The first =
part explaining Timing Advertisement messages is great, but the rest of the=
 commentary is unnecessary and not needed. We don=92t speculate the protoco=
l adoption success in IETF specifications,
 or about the experience level of the =93reviewer" :)


[<=
/span>Fygs=
]: Absolutely
 agree.




   o&n=
bsp; Frequency range: this is a characteristic of the PHY layer, with


  &nbs=
p;   almost no impact to the interface between MAC and IP.  =
However, it


  &nbs=
p;   is worth considering that the frequency range is regulated b=
y a


  &nbs=
p;   regional authority (ARCEP, ETSI, FCC, etc.); as part of the<=
/font>


  &nbs=
p;   regulation process, specific applications are associated wit=
h


  &nbs=
p;   specific frequency ranges.  In the case of 802.11-OCB, =
the


  &nbs=
p;   regulator associates a set of frequency ranges, or slots wit=
hin a


  &nbs=
p;   band, to the use of applications of vehicular communications=
, in a


  &nbs=
p;   band known as "5.9GHz".  This band is "5=
.9GHz" which is different


  &nbs=
p;   from the bands "2.4GHz" or "5GHz" used b=
y Wireless LAN.  However,


  &nbs=
p;   as with Wireless LAN, the operation of 802.11-OCB in "5=
.9GHz"


  &nbs=
p;   bands is exempt from owning a license in EU (in US the 5.9GH=
z is a


  &nbs=
p;   licensed band of spectrum; for the the fixed infrastructure =
an


  &nbs=
p;   explicit FCC autorization is required; for an onboard device=
 a


  &nbs=
p;   'licensed-by-rule' concept applies: rule certification confo=
rmity


  &nbs=
p;   is required); however technical conditions are different tha=
n


  &nbs=
p;   those of the bands "2.4GHz" or "5GHz".&n=
bsp; On one hand, the allowed


  &nbs=
p;   power levels, and implicitly the maximum allowed distance be=
tween


  &nbs=
p;   vehicles, is of 33dBm for 802.11-OCB (in Europe), compared t=
o 20


  &nbs=
p;   dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum<=
/font>


  &nbs=
p;   distance of approximately 1km, compared to approximately 50m=
.  On


  &nbs=
p;   the other hand, specific conditions related to congestion


  &nbs=
p;   avoidance, jamming avoidance, and radar detection are impose=
d on


  &nbs=
p;   the use of DSRC (in US) and on the use of frequencies for


  &nbs=
p;   Intelligent Transportation Systems (in EU), compared to Wire=
less


  &nbs=
p;   LAN (802.11a/b/g/n).


   o&n=
bsp; Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB,


  &nbs=
p;   as opposed to IPv6 not being prohibited on any channel on wh=
ich


  &nbs=
p;   802.11a/b/g/n runs:


  &nbs=
p;   *  Some channels are reserved for safety communications=
; the IPv6


  &nbs=
p;      packets should not be sent on these channe=
ls.










Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;           &nbs=
p; [Page 9]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-10


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




  &nbs=
p;   *  At the time of writing, the prohibition is explicit =
at higher


  &nbs=
p;      layer protocols providing services to the =
application; these


  &nbs=
p;      higher layer protocols are specified in IE=
EE 1609 documents.


  &nbs=
p;   *  National or regional specifications and regulations =
specify the


  &nbs=
p;      use of different channels; these regulatio=
ns must be followed.


   o&n=
bsp; 'Half-rate' encoding: as the frequency range, this parameter is=



  &nbs=
p;   related to PHY, and thus has not much impact on the interfac=
e


  &nbs=
p;   between the IP layer and the MAC layer.


   o&n=
bsp; In vehicular communications using 802.11-OCB links, there are


  &nbs=
p;   strong privacy requirements with respect to addressing. =
; While the


  &nbs=
p;   802.11-OCB standard does not specify anything in particular =
with


  &nbs=
p;   respect to MAC addresses, in these settings there exists a s=
trong


  &nbs=
p;   need for dynamic change of these addresses (as opposed to th=
e non-


  &nbs=
p;   vehicular settings - real wall protection - where fixed MAC<=
/font>


  &nbs=
p;   addresses do not currently pose some privacy risks).  T=
his is


  &nbs=
p;   further described in section

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-7.  A relevant function is


  &nbs=
p;   described in IEEE 1609.3-2016 [https://t=
ools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee1609.3],
 clause 5.5.1 and IEEE


  &nbs=
p;   1609.4-2016 [https://tools.ietf.org/html=
/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee1609.4], clause
 6.7.


   Oth=
er aspects particular to 802.11-OCB which are also particular to


   802=
.11 (e.g. the 'hidden node' operation) may have an influence on


   the=
 use of transmission of IPv6 packets on 802.11-OCB networks.  The


   sub=
net structure which may be assumed in 802.11-OCB networks is<=
/p>

   str=
ongly influenced by the mobility of vehicles.




[Sri] Per my ear=
lier comment, the link model, addressing ..etc needs to be explained in mor=
e detail. It is not clear what exactly the =93subnet structure=94 that is a=
ssumed in 802.11-OCB.


h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
5.  Layering of IPv6 over 802.11-OCB
 as over Ethernet




https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sectio=
n-5.1.  Maximum Transmission Unit (MTU)




   The=
 default MTU for IP packets on 802.11-OCB is 1500 octets.  It is


   the=
 same value as IPv6 packets on Ethernet links, as specified in


   [https://tools.ietf.org/html/r=
fc2464].  This value of the MTU respects the recommendation that


   eve=
ry link in the Internet must have a minimum MTU of 1280 octets


   (st=
ated in [https://tools.ietf=
.org/html/rfc2460], and the recommendations therein, especially<=
/span>


   wit=
h respect to fragmentation).  If IPv6 packets of size larger than


   150=
0 bytes are sent on an 802.11-OCB interface card then the IP stack


   wil=
l fragment.  In case there are IP fragments, the field "Sequence<=
/font>


   num=
ber" of the 802.11 Data header containing the IP fragment field is


   inc=
reased.


   Non=
-IP packets such as WAVE Short Message Protocol (WSMP) can be=



   del=
ivered on 802.11-OCB links.  Specifications of these packets are


   out=
 of scope of this document, and do not impose any limit on the MTU


   siz=
e, allowing an arbitrary number of 'containers'.  Non-IP packets


   suc=
h as ETSI 'geonet' packets have an MTU of 1492 bytes.






Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 10]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-11


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   The=
 Equivalent Transmit Time on Channel is a concept that may be used


   as =
an alternative to the MTU concept.  A rate of transmission may be


   spe=
cified as well.  The ETTC, rate and MTU may be in direct=



   rel=
ationship.


[Sri] The last p=
aragraph needs some additional context. Did 802.11-OCB introduce ETTC conce=
pt?


[Fygs] NO ! 







https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sectio=
n-5.2.  Frame Format




   IP =
packets are transmitted over 802.11-OCB as standard Ethernet<=
/p>

   pac=
kets.  As with all 802.11 frames, an Ethernet adaptation layer is


   use=
d with 802.11-OCB as well.  This Ethernet Adaptation Layer


   per=
forming 802.11-to-Ethernet is described in

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.2.1.  The


   Eth=
ernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD,


   or =
otherwise #86DD).


   The=
 Frame format for transmitting IPv6 on 802.11-OCB networks is the


   sam=
e as transmitting IPv6 on Ethernet networks, and is described in


   
https://tools.ietf.org/html/rfc2464#section-3.  The frame format f=
or transmitting IPv6


   pac=
kets over Ethernet is illustrated below:




  &nbs=
p;            &=
nbsp;    0        &n=
bsp;          1<=
/p>

  &nbs=
p;            &=
nbsp;    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5


  &nbs=
p;            &=
nbsp;    +-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp; Destination          |


  &nbs=
p;            &=
nbsp;    +-       &nb=
sp;            =
         -+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp;   Ethernet        &n=
bsp;  |


  &nbs=
p;            &=
nbsp;    +-       &nb=
sp;            =
         -+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp;   Address        &nb=
sp;   |


  &nbs=
p;            &=
nbsp;    +-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp;    Source       &nbs=
p;    |


  &nbs=
p;            &=
nbsp;    +-       &nb=
sp;            =
         -+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp;   Ethernet        &n=
bsp;  |


  &nbs=
p;            &=
nbsp;    +-       &nb=
sp;            =
         -+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp;   Address        &nb=
sp;   |


  &nbs=
p;            &=
nbsp;    +-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|


  &nbs=
p;            &=
nbsp;    +-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp;    IPv6        =
      |


  &nbs=
p;            &=
nbsp;    +-       &nb=
sp;            =
         -+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp;   header        &nbs=
p;    |


  &nbs=
p;            &=
nbsp;    +-       &nb=
sp;            =
         -+


  &nbs=
p;            &=
nbsp;    |        &n=
bsp;    and        &=
nbsp;      |


  &nbs=
p;            &=
nbsp;    +-       &nb=
sp;            =
         -+


  &nbs=
p;            &=
nbsp;    /        &n=
bsp;   payload ...        /


  &nbs=
p;            &=
nbsp;    +-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;    (Each tic mark represents one bit.)









Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 11]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-12


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   Eth=
ernet II Fields:


   Des=
tination Ethernet Address


  &nbs=
p;   the MAC destination address.


   Sou=
rce Ethernet Address


  &nbs=
p;   the MAC source address.


   1 0=
 0 0 0 1 1 0 1 1 0 1 1 1 0 1


  &nbs=
p;   binary representation of the EtherType value 0x86DD.<=
/span>


   IPv=
6 header and payload


  &nbs=
p;   the IPv6 packet containing IPv6 header and payload.


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-5.2.1.  Ethernet Adaptation Layer




   In =
general, an 'adaptation' layer is inserted between a MAC layer and


   the=
 Networking layer.  This is used to transform some parameters


   bet=
ween their form expected by the IP stack and the form provided by


   the=
 MAC layer.  For example, an 802.15.4 adaptation layer may perform


   fra=
gmentation and reassembly operations on a MAC whose maximum Packet


   Dat=
a Unit size is smaller than the minimum MTU recognized by the IPv6


   Net=
working layer.  Other examples involve link-layer address


   tra=
nsformation, packet header insertion/removal, and so on.


   An =
Ethernet Adaptation Layer makes an 802.11 MAC look to IP


   Net=
working layer as a more traditional Ethernet layer.  At reception,


   thi=
s layer takes as input the IEEE 802.11 Data Header and the

   Log=
ical-Link Layer Control Header and produces an Ethernet II Header.


   At =
sending, the reverse operation is performed.




 +-----=
---------------+------------+-------------+---------+------=
-----+


 | 802.11 D=
ata Header | LLC Header | IPv6 Header | Payload |.11 Trailer|=



 +-----=
---------------+------------+-------------+---------+------=
-----+


  \ &n=
bsp;            =
;            &n=
bsp;    /        &nb=
sp;            =
    \         /


  &nbs=
p; -----------------------------       &=
nbsp;           &nbs=
p;         --------

  &nbs=
p;            &=
nbsp;   ^---------------------------------------------/


  &nbs=
p;            &=
nbsp;   |


  &nbs=
p;        802.11-to-Ethernet Adaptation =
Layer


  &nbs=
p;            &=
nbsp;   |


  &nbs=
p;            &=
nbsp;   v


 +-----=
----------------+-------------+---------+


 | Ethernet=
 II Header  | IPv6 Header | Payload |


 +-----=
----------------+-------------+---------+












Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 12]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-13


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   The=
 Receiver and Transmitter Address fields in the 802.11 Data Header


   con=
tain the same values as the Destination and the Source Address


   fie=
lds in the Ethernet II Header, respectively.  The value of the<=
/span>


   Typ=
e field in the LLC Header is the same as the value of the Type


   fie=
ld in the Ethernet II Header.


   The=
 ".11 Trailer" contains solely a 4-byte Frame Check Sequence.


   The=
 Ethernet Adaptation Layer performs operations in relation to IP


   fra=
gmentation and MTU.  One of these operations is briefly described


   in =
section 
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-5.1.


   In =
OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11


   Dat=
a" or alternatively as "IEEE 802.11 QoS Data", as illustrate=
d in


   the=
 following figure:




+-----------=
---------+-------------+-------------+---------+-----------=
+


| 802.11 Data He=
ader | LLC Header  | IPv6 Header | Payload |.11 Trailer|=



+-----------=
---------+-------------+-------------+---------+-----------=
+


or=



+-----------=
---------+-------------+-------------+---------+-----------=
+


| 802.11 QoS Dat=
a Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|=



+-----------=
---------+-------------+-------------+---------+-----------=
+




   The=
 distinction between the two formats is given by the value of the


   fie=
ld "Type/Subtype".  The value of the field "Type/Subtyp=
e" in the


   802=
.11 Data header is 0x0020.  The value of the field "Type/Subtype&=
quot;


   in =
the 802.11 QoS header is 0x0028.


   The=
 mapping between qos-related fields in the IPv6 header (e.g.<=
/p>

   &qu=
ot;Traffic Class", "Flow label") and fields in the "802=
.11 QoS Data


   Hea=
der" (e.g.  "QoS Control") are not specified in this do=
cument.


   Gui=
dance for a potential mapping is provided in


   [https://tools.ietf.org/html/draft-ietf-ip=
wave-ipv6-over-80211ocb-04#ref-I-D.ietf-tsvwg-ieee-802-11],
 although it is not specific to OCB


   mod=
e.






[Sri] The applic=
ability of the QoS mapping draft to 802.11-OCB needs further investigation,=
 IMO.


<=
font face=3D"Calibri">[Fygs] I am not familiar with QoS control of IPv6.  As for the OCB MAC QoS
 it is somewhat involved.  It is based on<=
span lang=3D"en-us">transmission
 priority of MAC frames.  A higher priority f=
rame is intended to be transmitted ahead of lower priority frames. <=
font face=3D"Calibri">
 If a detail process is required, please, let me know and I would provide t=
he text.






https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sectio=
n-5.3.  Link-Local Addresses




   The=
 link-local address of an 802.11-OCB interface is formed in the


   sam=
e manner as on an Ethernet interface.  This manner is described in


   
https://tools.ietf.org/html/rfc2464#section-5.






[Sri] Does this =
go against the 8064 recommendation on Interface identifier generation?


May be RFC7217 f=
or interface identifier generation in conjunction with the link-local addre=
ss generation per RFC2464










Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 13]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sectio=
n-5.4.  Address Mapping




   For=
 unicast as for multicast, there is no change from the unicast and


   mul=
ticast address mapping format of Ethernet interfaces, as defined


   by =
sections 
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-6 and

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-7 of [https://tools.ie=
tf.org/html/rfc2464].






[Sri] RFC6085 sp=
ecified mapping is also relevant; If the communication peers are aware that=
 there is only one peer, it should apply 6085 specified mapping. That mode =
is relevant for 802.11-OCB types links
 as well.




https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-5.4.1.  Address Mapping -- Unicast




   The=
 procedure for mapping IPv6 unicast addresses into Ethernet link-


   lay=
er addresses is described in [https://tools.ietf.org/html/rfc4861].  The Source/Target Link-<=
/font>


   lay=
er Address option has the following form when the link-layer is


   Eth=
ernet.


[Sri] I thought,=
 mapping of IPv6 unicast addresses to Ethernet link-layer addresses is spec=
ified in section 6, of RFC2464 and not in RFC4861.






  &nbs=
p;            &=
nbsp;      0      &n=
bsp;            1


  &nbs=
p;            &=
nbsp;      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5<=
/span>


  &nbs=
p;            &=
nbsp;     +-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;     |     Type  &nb=
sp;   |    Length     |=



  &nbs=
p;            &=
nbsp;     +-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;     |       &n=
bsp;            =
;           |


  &nbs=
p;            &=
nbsp;     +-      &nb=
sp;   Ethernet        &nb=
sp;  -+


  &nbs=
p;            &=
nbsp;     |       &n=
bsp;            =
;           |


  &nbs=
p;            &=
nbsp;     +-      &nb=
sp;    Address       &nbs=
p;   -+


  &nbs=
p;            &=
nbsp;     |       &n=
bsp;            =
;           |


  &nbs=
p;            &=
nbsp;     +-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+




   Opt=
ion fields:


   Typ=
e


  &nbs=
p;   1 for Source Link-layer address.


  &nbs=
p;   2 for Target Link-layer address.


   Len=
gth


  &nbs=
p;   1 (in units of 8 octets).


   Eth=
ernet Address


  &nbs=
p;   The 48 bit Ethernet IEEE 802 address, in canonical bit order=
.


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sect=
ion-5.4.2.  Address Mapping -- Multicast




   IPv=
6 protocols often make use of IPv6 multicast addresses in the=



   des=
tination field of IPv6 headers.  For example, an ICMPv6 link-


   sco=
ped Neighbor Advertisement is sent to the IPv6 address ff02::1


   den=
oted "all-nodes" address.  When transmitting these packets o=
n


   802=
.11-OCB links it is necessary to map the IPv6 address to a MAC


   add=
ress.








Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 14]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-15


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   The=
 same mapping requirement applies to the link-scoped multicast


   add=
resses of other IPv6 protocols as well.  In DHCPv6, the<=
/p>

   &qu=
ot;All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF the=



   &qu=
ot;All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped<=
/font>


   on =
a multicast MAC address.


   An =
IPv6 packet with a multicast destination address DST, consisting


   of =
the sixteen octets DST[1] through DST[16], is transmitted to the


   IEE=
E 802.11-OCB MAC multicast address whose first two octets are the


   val=
ue 0x3333 and whose last four octets are the last four octets of


   DST=
.


[Sri] Please add=
 a reference to Section 7, RFC4861 and also RFC6085. In general, for both u=
nicast and multicast, you may want to clearly say that this is per the exis=
ting specs and duplicated here for convenience.



  &nbs=
p;            &=
nbsp;     +-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;     |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|


  &nbs=
p;            &=
nbsp;     +-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;     |   DST[13]    =
 |   DST[14]     |


  &nbs=
p;            &=
nbsp;     +-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;            &=
nbsp;     |   DST[15]    =
 |   DST[16]     |


  &nbs=
p;            &=
nbsp;     +-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+




   A G=
roup ID TBD of length 112bits may be requested from IANA; this


   Gro=
up ID signifies "All 80211OCB Interfaces Address".  Only the=
 least


   32 =
significant bits of this "All 80211OCB Interfaces Address" will b=
e


   map=
ped to and from a MAC multicast address.


   Tra=
nsmitting IPv6 packets to multicast destinations over 802.11 links


   pro=
ved to have some performance issues


   [https://tools.ietf.org/html/dr=
aft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.perkins-intarea-multicast-iee=
e802]. 
 These issues may be


   exa=
cerbated in OCB mode.  Solutions for these problems should


   con=
sider the OCB mode of operation.


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sectio=
n-5.5.  Stateless Autoconfiguration




   The=
 Interface Identifier for an 802.11-OCB interface is formed using


   the=
 same rules as the Interface Identifier for an Ethernet interface;


   thi=
s is described in 
https://tools.ietf.org/html/rfc2464#section-4.  No changes are nee=
ded,


   but=
 some care must be taken when considering the use of the SLAAC


   pro=
cedure.




[Sri] Per my ear=
lier comment, please refer to the current recommendation on interface-ident=
ifier generation and its use in link-local, global or other addresses.




   The=
 bits in the the interface identifier have no generic meaning and


   the=
 identifier should be treated as an opaque value.  The bits


   'Un=
iversal' and 'Group' in the identifier of an 802.11-OCB interface


   are=
 significant, as this is an IEEE link-layer address.  The details


   of =
this significance are described in [https://tools=
.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.ietf-6man-ug=
].










Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 15]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-16


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   As =
with all Ethernet and 802.11 interface identifiers ([https://tools.ietf.org/html/rfc7721]),=



   the=
 identifier of an 802.11-OCB interface may involve privacy risks.


   A v=
ehicle embarking an On-Board Unit whose egress interface is

   802=
.11-OCB may expose itself to eavesdropping and subsequent


   cor=
relation of data; this may reveal data considered private by the


   veh=
icle owner; there is a risk of being tracked; see the privacy=



   con=
siderations described in

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.




[Sri] I think th=
ere are other security issues here; the absence of link-layer security open=
s up Mac-spoofing and IP address hijacking.  That should be mentioned.=





   If =
stable Interface Identifiers are needed in order to form IPv6=



   add=
resses on 802.11-OCB links, it is recommended to follow the

   rec=
ommendation in [https://tools.ietf.org/=
html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.ietf-6man-default-iids=
].


https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sectio=
n-5.6.  Subnet Structure




   The=
 802.11 networks in OCB mode may be considered as 'ad-hoc'

   net=
works.  The addressing model for such networks is described in<=
/span>


   [https://tools.ietf.org/html/r=
fc5889].




[Sri] Per my ear=
lier comment, there is no system level view of the network where 802.11-OCB=
 links are used. So, in the absence of such discussion So, I am not sure wh=
at part of RFC5889 is applicable here.
 For example, link-local addresses may just work fine. 




h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
6.  Example IPv6 Packet captured over
 a IEEE 802.11-OCB link




   We =
remind that a main goal of this document is to make the case that


   IPv=
6 works fine over 802.11-OCB networks.  Consequently, this section


   is =
an illustration of this concept and thus can help the implementer


   whe=
n it comes to running IPv6 over IEEE 802.11-OCB.  By way of


   exa=
mple we show that there is no modification in the headers when


   tra=
nsmitted over 802.11-OCB networks - they are transmitted like any


   oth=
er 802.11 and Ethernet packets.


   We =
describe an experiment of capturing an IPv6 packet on an


   802=
.11-OCB link.  In this experiment, the packet is an IPv6 Router=



   Adv=
ertisement.  This packet is emitted by a Router on its 802.11-OCB


   int=
erface.  The packet is captured on the Host, using a network


   pro=
tocol analyzer (e.g.  Wireshark); the capture is performed in two


   dif=
ferent modes: direct mode and 'monitor' mode.  The topology used


   dur=
ing the capture is depicted below.




  &nbs=
p;           +-------=
-+           &nb=
sp;            =
        +-------+<=
/p>

  &nbs=
p;           |  =
;      |       =
 802.11-OCB Link         | &nb=
sp;     |


  &nbs=
p;        ---| Router |-----------------=
---------------| Host  |


  &nbs=
p;           |  =
;      |       =
            &nb=
sp;            |&nbs=
p;      |


  &nbs=
p;           +-------=
-+           &nb=
sp;            =
        +-------+<=
/p>



   Dur=
ing several capture operations running from a few moments to<=
/p>

   sev=
eral hours, no message relevant to the BSSID contexts were

   cap=
tured (no Association Request/Response, Authentication Req/Resp,








Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 16]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-17


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   Bea=
con).  This shows that the operation of 802.11-OCB is outside the


   con=
text of a BSSID.


   Ove=
rall, the captured message is identical with a capture of an IPv6


   pac=
ket emitted on a 802.11b interface.  The contents are precisely=



   sim=
ilar.




[Sri] I suggest =
moving this discussion under the section =93Implementation Status=94, which=
 will eventually be removed from the RFC. There is nothing new here. This a=
re details on experimentation. But, if you
 think there is some useful information  such as discussion on Capture=
 mode ..etc, you may want to move this entire section to Appendix. Implemen=
tors may use these tools for verification.






https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#sectio=
n-6.1.  Capture in Monitor Mode




   The=
 IPv6 RA packet captured in monitor mode is illustrated below.


   The=
 radio tap header provides more flexibility for reporting the=



   cha=
racteristics of frames.  The Radiotap Header is prepended by this


   par=
ticular stack and operating system on the Host machine to the RA


   pac=
ket received from the network (the Radiotap Header is not present


   on =
the air).  The implementation-dependent Radiotap Header is useful


   for=
 piggybacking PHY information from the chip's registers as data in


   a p=
acket understandable by userland applications using Socket

   int=
erfaces (the PHY interface can be, for example: power levels, data


   rat=
e, ratio of signal to noise).


   The=
 packet present on the air is formed by IEEE 802.11 Data Header,


   Log=
ical Link Control Header, IPv6 Base Header and ICMPv6 Header.=







  &nbs=
p;  Radiotap Header v0


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |Header Revision|  Header Pad   |   =
 Header length          &=
nbsp;   |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;            &n=
bsp; Present flags         &nb=
sp;            =
   |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  | Data Rate     |     =
;        Pad    &nbs=
p;            &=
nbsp;           &nbs=
p; |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  IEEE 802.11 Data Header


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |  Type/Subtype and Frame Ctrl  |    =
;      Duration      =
;       |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;           Receiver Addr=
ess...


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  ... Receiver Address       &nbs=
p;   |      Transmitter Address...


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  ... Transmitter Address       &=
nbsp;           &nbs=
p;            &=
nbsp;       |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;            &n=
bsp;    BSS Id...


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  ... BSS Id         &n=
bsp;           |  Fr=
ag Number and Seq Number   |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+






Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 17]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-18


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




  &nbs=
p;  Logical-Link Control Header


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |      DSAP   |I|  &n=
bsp;  SSAP    |C| Control field | Org. code...


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  ... Organizational Code        =
|             T=
ype            =
  |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  IPv6 Base Header


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |Version| Traffic Class |       =
;    Flow Label       &nb=
sp;          |

  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |         Payload Length&n=
bsp;       |  Next Header  | &=
nbsp; Hop Limit   |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;            &=
nbsp;           &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;  Source Address        &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;            &=
nbsp;           &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;            &=
nbsp;           &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           Destinati=
on Address           =
;           +<=
/span>


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;            &=
nbsp;           &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  Router Advertisement


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |     Type      |&nbs=
p;    Code      |   =
       Checksum     =
        |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  | Cur Hop Limit |M|O|  Reserved |    &nbs=
p;  Router Lifetime         |<=
/font>


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;            &n=
bsp; Reachable Time         &n=
bsp;            =
;  |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;            &n=
bsp;  Retrans Timer        &nb=
sp;            =
   |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |   Options ...


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-




   The=
 value of the Data Rate field in the Radiotap header is set to 6


   Mb/=
s.  This indicates the rate at which this RA was received.










Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 18]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-19


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   The=
 value of the Transmitter address in the IEEE 802.11 Data Header


   is =
set to a 48bit value.  The value of the destination address is<=
/span>


   33:=
33:00:00:00:1 (all-nodes multicast address).  The value of the BSS


   Id =
field is ff:ff:ff:ff:ff:ff, which is recognized by the network


   pro=
tocol analyzer as being "broadcast".  The Fragment number an=
d


   seq=
uence number fields are together set to 0x90C6.


   The=
 value of the Organization Code field in the Logical-Link Control


   Hea=
der is set to 0x0, recognized as "Encapsulated Ethernet".  T=
he


   val=
ue of the Type field is 0x86DD (hexadecimal 86DD, or otherwise


   #86=
DD), recognized as "IPv6".


   A R=
outer Advertisement is periodically sent by the router to


   mul=
ticast group address ff02::1.  It is an icmp packet type 134.  Th=
e


   IPv=
6 Neighbor Discovery's Router Advertisement message contains an


   8-b=
it field reserved for single-bit flags, as described in [https://tools.ietf.org/html/rfc4861].


   The=
 IPv6 header contains the link local address of the router

   (so=
urce) configured via EUI-64 algorithm, and destination address set


   to =
ff02::1.  Recent versions of network protocol analyzers (e.g.


   Wir=
eshark) provide additional informations for an IP address, if a


   geo=
localization database is present.  In this example, the<=
/p>

   geo=
localization database is absent, and the "GeoIP" information is


   set=
 to unknown for both source and destination addresses (although


   the=
 IPv6 source and destination addresses are set to useful values).


   Thi=
s "GeoIP" can be a useful information to look up the city,=



   cou=
ntry, AS number, and other information for an IP address.


[Sri] Not sure, =
why all of this text should be in the specification.



   The=
 Ethernet Type field in the logical-link control header is set to


   0x8=
6dd which indicates that the frame transports an IPv6 packet.  In


   the=
 IEEE 802.11 data, the destination address is 33:33:00:00:00:01


   whi=
ch is he corresponding multicast MAC address.  The BSS id is a<=
/span>


   bro=
adcast address of ff:ff:ff:ff:ff:ff.  Due to the short link


   dur=
ation between vehicles and the roadside infrastructure, there is


   no =
need in IEEE 802.11-OCB to wait for the completion of association


   and=
 authentication procedures before exchanging data.  IEEE=



   802=
.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s)


   and=
 may start communicating as soon as they arrive on the


  communication channel.


ht=
tps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-6=
.2. Capt=
ure
 in Normal Mode




   The=
 same IPv6 Router Advertisement packet described above (monitor


   mod=
e) is captured on the Host, in the Normal mode, and depicted<=
/p>

   bel=
ow.












Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 19]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-20


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




  &nbs=
p; Ethernet II Header


   &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+


   &=
nbsp; |           &n=
bsp;           Destinatio=
n...


   &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+


   &=
nbsp; ...Destination         &=
nbsp;       |     &n=
bsp;     Source...


   &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+


   &=
nbsp; ...Source          =
            &nb=
sp;            =
            &nb=
sp;      |


   &=
nbsp;+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+


  &nbs=
p;  |          Type =
            &nb=
sp;   |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+


  &nbs=
p;  IPv6 Base Header


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |Version| Traffic Class |       =
;    Flow Label       &nb=
sp;          |

  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |         Payload Length&n=
bsp;       |  Next Header  | &=
nbsp; Hop Limit   |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;            &=
nbsp;           &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;  Source Address        &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;            &=
nbsp;           &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;            &=
nbsp;           &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           Destinati=
on Address           =
;           +<=
/span>


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +          &=
nbsp;           &nbs=
p;            &=
nbsp;           &nbs=
p;            &=
nbsp;  +


  &nbs=
p;  |           =
;            &n=
bsp;            =
;            &n=
bsp;            =
;  |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  Router Advertisement


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  |     Type      |&nbs=
p;    Code      |   =
       Checksum     =
        |


  &nbs=
p;  +-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+


  &nbs=
p;  | Cur Hop Limit |M|O|  Reserved |    &nbs=
p;  Router Lifetime         |<=
/font>


  &nbs=
p; +-+-+-+-+-+-+-+-+-+=
-+-+-+-+-+-+-+-+-+-+-+-+-&#=
43;-+-+-+-+-+-+-+-+-+-+


   &=
nbsp; |           &n=
bsp;            =
; Reachable Time          =
;            &n=
bsp; |


   &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+


   &=
nbsp; |           &n=
bsp;            =
;  Retrans Timer         =
            &nb=
sp;  |


   &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-+-+-+-+-+-+-+-+-+-+-+-+-=
+-+-+-+-+-+-+-+-+


   &=
nbsp; |   Options ...


   &=
nbsp; +-+-+-+-+-+-+-+-+-+-+-=
3;-










Petrescu, et al.&nb=
sp;      <=
font face=3D"Calibri">Expires February 18, 2018    &nbs=
p;         [Page 20]<=
/p>

________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-21


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   One=
 notices that the Radiotap Header is not prepended, and that the


   IEE=
E 802.11 Data Header and the Logical-Link Control Headers are not


   pre=
sent.  On another hand, a new header named Ethernet II Header is


   pre=
sent.


   The=
 Destination and Source addresses in the Ethernet II header

   con=
tain the same values as the fields Receiver Address and


   Tra=
nsmitter Address present in the IEEE 802.11 Data Header in the


   &qu=
ot;monitor" mode capture.


   The=
 value of the Type field in the Ethernet II header is 0x86DD<=
/p>

   (re=
cognized as "IPv6"); this value is the same value as the value of=



   the=
 field Type in the Logical-Link Control Header in the "monitor"


   mod=
e capture.


   The=
 knowledgeable experimenter will no doubt notice the similarity of


   thi=
s Ethernet II Header with a capture in normal mode on a pure<=
/p>

   Eth=
ernet cable interface.


   It =
may be interpreted that an Adaptation layer is inserted in a pure


   IEE=
E 802.11 MAC packets in the air, before delivering to the


   app=
lications.  In detail, this adaptation layer may consist in


   eli=
mination of the Radiotap, 802.11 and LLC headers and insertion of


   the=
 Ethernet II header.  In this way, it can be stated that IPv6 runs


   nat=
urally straight over LLC over the 802.11-OCB MAC layer, as shown


   by =
the use of the Type 0x86DD, and assuming an adaptation layer<=
/p>

   (ad=
apting 802.11 LLC/MAC to Ethernet II header).


h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
7.  Security Considerations




   Any=
 security mechanism at the IP layer or above that may be carried


   out=
 for the general case of IPv6 may also be carried out for IPv6


   ope=
rating over 802.11-OCB.


   802=
.11-OCB does not provide any cryptographic protection, because it


   ope=
rates outside the context of a BSS (no Association Request/

   Res=
ponse, no Challenge messages).  Any attacker can therefore just=



   sit=
 in the near range of vehicles, sniff the network (just set the


   int=
erface card's frequency to the proper range) and perform attacks


   wit=
hout needing to physically break any wall.  Such a link is way<=
/span>


   les=
s protected than commonly used links (wired link or protected=



   802=
.11).


[Sri] Per my ear=
lier comment, there is more than one attack vector possible

1.) Absence of l=
ink-layer security and the potential for mac address spoofing



2.) IP address /=
 Session hijacking



3.) Data pr=
ivacy per your text




   At =
the IP layer, IPsec can be used to protect unicast communications,


   and=
 SeND can be used for multicast communications. 


[Sri] IPSec can =
be used for protecting both multicast or unicast communication; RFC-5374 wi=
th GDOI.






 If no prot=
ection


   is =
used by the IP layer, upper layers should be protected.


   Oth=
erwise, the end-user or system should be warned about the risks


   the=
y run.






Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 21]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   As =
with all Ethernet and 802.11 interface identifiers, there may=



   exi=
st privacy risks in the use of 802.11-OCB interface identifiers.


   Mor=
eover, in outdoors vehicular settings, the privacy risks are more


   imp=
ortant than in indoors settings.  New risks are induced by the<=
/span>


   pos=
sibility of attacker sniffers deployed along routes which listen


   for=
 IP packets of vehicles passing by.  For this reason, in the


   802=
.11-OCB deployments, there is a strong necessity to use protection


   too=
ls such as dynamically changing MAC addresses.  This may help


   mit=
igate privacy risks to a certain level.  On another hand, it may


   hav=
e an impact in the way typical IPv6 address auto-configuration is


   per=
formed for vehicles (SLAAC would rely on MAC addresses amd would


   hen=
ce dynamically change the affected IP address), in the way the


   IPv=
6 Privacy addresses were used, and other effects.


h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
8.  IANA Considerations




h=
ttps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-=
9.  Contributors




   Rom=
ain Kuntz contributed extensively about IPv6 handovers between


   lin=
ks running outside the context of a BSS (802.11-OCB links).

   Tim=
 Leinmueller contributed the idea of the use of IPv6 over


   802=
.11-OCB for distribution of certificates.


   Mar=
ios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey


   Vor=
onov provided significant feedback on the experience of using IP


   mes=
sages over 802.11-OCB in initial trials.


   Mic=
helle Wetterwald contributed extensively the MTU discussion,<=
/p>

   off=
ered the ETSI ITS perspective, and reviewed other parts of the


   doc=
ument.


=
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-10.  Acknowledgements




   The=
 authors would like to thank Witold Klaudel, Ryuji Wakikawa,<=
/p>

   Emm=
anuel Baccelli, John Kenney, John Moring, Francois Simon, Dan=



   Rom=
ascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray


   Hun=
ter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan,


   Din=
o Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne,=



   Han=
s-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark,


   Bob=
 Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and


   Wil=
liam Whyte.  Their valuable comments clarified certain issues and


   gen=
erally helped to improve the document.


   Pie=
rre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB

   dri=
vers for linux and described how.










Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 22]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-23


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   For=
 the multicast discussion, the authors would like to thank Owen


   DeL=
ong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and

   par=
ticipants to discussions in network working groups.


   The=
 authours would like to thank participants to the Birds-of-

   a-F=
eather "Intelligent Transportation Systems" meetings held at IETF=



   in =
2016.


=
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section=
-11.  References




   [I-=
D.ietf-6man-default-iids]


  &nbs=
p;           Gont, F., Co=
oper, A., Thaler, D., and S. LIU,


  &nbs=
p;           "Recomm=
endation on Stable IPv6 Interface Identifiers",


  &nbs=
p;           
https://tools.ietf.org/html/draft-ietf-6man-default-iids-16 (work in pr=
ogress),


  &nbs=
p;           September 20=
16.


   [I-=
D.ietf-6man-ug]


  &nbs=
p;           Carpenter, B=
. and S. Jiang, "Significance of IPv6


  &nbs=
p;           Interface Id=
entifiers",
https://tools=
.ietf.org/html/draft-ietf-6man-ug-06 (work in


  &nbs=
p;           progress), D=
ecember 2013.


   [I-=
D.ietf-tsvwg-ieee-802-11]


  &nbs=
p;           Szigeti, T.,=
 Henry, J., and F. Baker, "Diffserv to IEEE


  &nbs=
p;           802.11 Mappi=
ng",
htt=
ps://tools.ietf.org/html/draft-ietf-tsvwg-ieee-802-11-06 (work in


  &nbs=
p;           progress), A=
ugust 2017.


   [RF=
C1042]  Postel, J. and J. Reynolds, "Standard for the transmissio=
n


  &nbs=
p;           of IP datagr=
ams over IEEE 802 networks", STD 43,
https://tools.ietf.org/html=
/rfc1042,


  &nbs=
p;           DOI 10.17487=
/RFC1042, February 1988, <https://www.rfc-editor.org/info/rfc1042


  &nbs=
p;           
https://www.rfc-editor.org/info/rfc1042>.


   [RF=
C2119]  Bradner, S., "Key words for use in RFCs to Indicate


  &nbs=
p;           Requirement =
Levels",
https://tools.ietf.org/html/b=
cp14,
https://tools.ietf.org/html=
/rfc2119,


  &nbs=
p;           DOI 10.17487=
/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119


  &nbs=
p;           
https://www.rfc-editor.org/info/rfc2119>.


   [RF=
C2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6<=
/font>


  &nbs=
p;           (IPv6) Speci=
fication",
https://tools.ietf.org/html=
/rfc2460, DOI 10.17487/RFC2460,


  &nbs=
p;           December 199=
8, <https://www.rfc-=
editor.org/info/rfc2460>.


   [RF=
C2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet=



  &nbs=
p;           Networks&quo=
t;, 
https://tools.ietf.org/html/rfc2464, DOI 10.17487/RFC2464, December 199=
8,


  &nbs=
p;           <https://www.rfc-editor.org/inf=
o/rfc2464>.












Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 23]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-24


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   [RF=
C3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.


  &nbs=
p;           Thubert, &qu=
ot;Network Mobility (NEMO) Basic Support Protocol",


  &nbs=
p;           
https://tools.ietf.org/html/rfc3963, DOI 10.17487/RFC3963, January 2005=
,


  &nbs=
p;           <https://www.rfc-editor.org/inf=
o/rfc3963>.


   [RF=
C4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,<=
/p>

  &nbs=
p;           "Random=
ness Requirements for Security",
https://tools.ietf.org/html/=
bcp106,
https://tools.ietf.org/html=
/rfc4086,


  &nbs=
p;          DOI 1=
0.17487/RFC4086, June 2005, <https://www.rfc-editor.org/info/rfc4086


   &=
nbsp;          
https://www.rfc-editor.org/info/rfc4086>.


  =
[RFC4301]  Kent, S.=
 and K. Seo, "Security Architecture for the


  &nbs=
p;          Inter=
net Protocol",
https://tools.ietf.org/html=
/rfc4301, DOI 10.17487/RFC4301,


   &=
nbsp;         December 2005, <https://www.rfc-editor.org/info/rfc43=
01>.


   [RF=
C4429]  Moore, N., "Optimistic Duplicate Address Detection (DAD)<=
/font>


  &nbs=
p;           for IPv6&quo=
t;, 
https://tools.ietf.org/html/rfc4429, DOI 10.17487/RFC4429, April 2006,<=
/font>


  &nbs=
p;           <https://www.rfc-editor.org/inf=
o/rfc4429>.


   [RF=
C4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,<=
/span>


  &nbs=
p;           "Neighb=
or Discovery for IP version 6 (IPv6)",
https://tools.ietf.org/html=
/rfc4861,


  &nbs=
p;           DOI 10.17487=
/RFC4861, September 2007, <https://www.rfc-editor.org/info/rfc4861


  &nbs=
p;           
https://www.rfc-editor.org/info/rfc4861>.


   [RF=
C5889]  Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing


  &nbs=
p;           Model in Ad =
Hoc Networks",
https://tools.ietf.org/html=
/rfc5889, DOI 10.17487/RFC5889,


  &nbs=
p;           September 20=
10, <https://www.rfc=
-editor.org/info/rfc5889>.


   [RF=
C6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility


  &nbs=
p;           Support in I=
Pv6",
https://tools.ietf.org/html=
/rfc6275, DOI 10.17487/RFC6275, July


  &nbs=
p;           2011, <https://www.rfc-editor.or=
g/info/rfc6275>.


   [RF=
C6775]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.<=
/span>


  &nbs=
p;           Bormann, &qu=
ot;Neighbor Discovery Optimization for IPv6 over


  &nbs=
p;           Low-Power Wi=
reless Personal Area Networks (6LoWPANs)",


  &nbs=
p;           
https://tools.ietf.org/html/rfc6775, DOI 10.17487/RFC6775, November 201=
2,


  &nbs=
p;           <https://www.rfc-editor.org/inf=
o/rfc6775>.


   [RF=
C7721]  Cooper, A., Gont, F., and D. Thaler, "Security and Privac=
y


  &nbs=
p;           Consideratio=
ns for IPv6 Address Generation Mechanisms",


  &nbs=
p;           
https://tools.ietf.org/html/rfc7721, DOI 10.17487/RFC7721, March 2016,<=
/font>


  &nbs=
p;           <https://www.rfc-editor.org/inf=
o/rfc7721>.


Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 24]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-25


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   [fc=
c-cc]   "'Report and Order, Before the Federal Communication=
s


  &nbs=
p;           Commission W=
ashington, D.C. 20554', FCC 03-324, Released


  &nbs=
p;           on February =
10, 2004, document FCC-03-324A1.pdf, document


  &nbs=
p;           freely avail=
able at URL


  &nbs=
p;           
http://www.its.dot.gov/exit/fcc_edocs.htm downloaded on

  &nbs=
p;           October 17th=
, 2013.".


   [fc=
c-cc-172-184]


  &nbs=
p;           "'Memor=
andum Opinion and Order, Before the Federal


  &nbs=
p;           Communicatio=
ns Commission Washington, D.C. 20554', FCC


  &nbs=
p;           06-10, Relea=
sed on July 26, 2006, document FCC-


  &nbs=
p;           06-110A1.pdf=
, document freely available at URL


  &nbs=
p;           
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A1.pdf


  &nbs=
p;           
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A1.pdf down=
loaded on June 5th, 2014.".


   [I-=
D.jeong-ipwave-vehicular-networking-survey]


  &nbs=
p;           Jeong, J., C=
espedes, S., Benamar, N., Haerri, J., and M.


  &nbs=
p;           Wetterwald, =
"Survey on IP-based Vehicular Networking for


  &nbs=
p;           Intelligent =
Transportation Systems",

https://tools.ietf.org/html/draft-jeong-ipwave-vehicular-networking-survey-=
03


  &nbs=
p;           
https://tools.ietf.org/html/draft-jeong-ipwave-vehicular-networking-survey-=
03 (work in progress), June


  &nbs=
p;           2017.=



   [I-=
D.perkins-intarea-multicast-ieee802]


  &nbs=
p;           Perkins, C.,=
 Stanley, D., Kumari, W., and J. Zuniga,


  &nbs=
p;           "Multic=
ast Considerations over IEEE 802 Wireless Media",


  &nbs=
p;           
https://tools.ietf.org/html/draft-perkins-intarea-multicast-ieee802-03 =
(work in


  &nbs=
p;           progress), J=
uly 2017.


   [I-=
D.petrescu-its-scenarios-reqs]


  &nbs=
p;           Petrescu, A.=
, Janneteau, C., Boc, M., and W. Klaudel,


  &nbs=
p;           "Scenar=
ios and Requirements for IP in Intelligent


  &nbs=
p;           Transportati=
on Systems",
https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs-03


  &nbs=
p;           
https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs-03 (work =
in progress), October 2013.


   [ie=
ee1609.2]


  &nbs=
p;           "IEEE S=
A - 1609.2-2016 - IEEE Standard for Wireless Access


  &nbs=
p;           in Vehicular=
 Environments (WAVE) -- Security Services for


  &nbs=
p;           Applications=
 and Management Messages.  Example URL


  &nbs=
p;           
http://ieeexplore.ieee.org/document/7426684/ accessed on<=
/p>

  &nbs=
p;           August 17th,=
 2017.".


   [ie=
ee1609.3]


  &nbs=
p;           "IEEE S=
A - 1609.3-2016 - IEEE Standard for Wireless Access


  &nbs=
p;           in Vehicular=
 Environments (WAVE) -- Networking Services.


  &nbs=
p;           Example URL =

http://ieeexplore.ieee.org/document/7458115/accessed


  &nbs=
p;           
http://ieeexplore.ieee.org/document/7458115/accessed on August 17th, 20=
17.".










Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 25]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-26


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   [ie=
ee1609.4]


  &nbs=
p;           "IEEE S=
A - 1609.4-2016 - IEEE Standard for Wireless Access


  &nbs=
p;           in Vehicular=
 Environments (WAVE) -- Multi-Channel


  &nbs=
p;           Operation.&n=
bsp; Example URL


  &nbs=
p;           
http://ieeexplore.ieee.org/document/7435228/ accessed on<=
/p>

  &nbs=
p;           August 17th,=
 2017.".


   [ie=
ee802.11-2012]


  &nbs=
p;           "802.11=
-2012 - IEEE Standard for Information technology--


  &nbs=
p;           Telecommunic=
ations and information exchange between


  &nbs=
p;           systems Loca=
l and metropolitan area networks--Specific


  &nbs=
p;           requirements=
 Part 11: Wireless LAN Medium Access Control


  &nbs=
p;           (MAC) and Ph=
ysical Layer (PHY) Specifications.  Downloaded


  &nbs=
p;           on October 1=
7th, 2013, from IEEE Standards, document


  &nbs=
p;           freely avail=
able at URL


  &nbs=
p;           
http://standards.ieee.org/findstds/standard/802.11-2012.html


  &nbs=
p;           
http://standards.ieee.org/findstds/standard/802.11-2012.html retrieved =
on October 17th,


  &nbs=
p;           2013.".=



   [ie=
ee802.11p-2010]


  &nbs=
p;           "IEEE S=
td 802.11p (TM)-2010, IEEE Standard for Information


  &nbs=
p;           Technology -=
 Telecommunications and information exchange


  &nbs=
p;           between syst=
ems - Local and metropolitan area networks -


  &nbs=
p;           Specific req=
uirements, Part 11: Wireless LAN Medium Access


  &nbs=
p;           Control (MAC=
) and Physical Layer (PHY) Specifications,


  &nbs=
p;           Amendment 6:=
 Wireless Access in Vehicular Environments;


  &nbs=
p;           document fre=
ely available at URL


  &nbs=
p;           
http://standards.ieee.org/getieee802/download/802.11p-2010.pdf


  &nbs=
p;           
http://standards.ieee.org/getieee802/download/802.11p-2010.pdf retrieve=
d on September 20th,


  &nbs=
p;           2013.".=



=
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-A.  ChangeLog




   The=
 changes are listed in reverse chronological order, most recent


   cha=
nges appearing at the top of the list.


   Fro=
m 
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03 to =

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04


   o&n=
bsp; Removed a few informative references pointing to Dx draft IEEE<=
/span>


  &nbs=
p;   1609 documents.


   o&n=
bsp; Removed outdated informative references to ETSI documents.


   o&n=
bsp; Added citations to IEEE 1609.2, .3 and .4-2016.


   o&n=
bsp; Minor textual issues.








Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 26]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-27


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   Fro=
m 
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02 to =

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03


   o&n=
bsp; Keep the previous text on multiple addresses, so remove talk about


  &nbs=
p;   MIP6, NEMOv6 and MCoA.


   o&n=
bsp; Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.


   o&n=
bsp; Clarified the figure showing Infrastructure mode and OCB mode side


  &nbs=
p;   by side.


   o&n=
bsp; Added a reference to the IP Security Architecture RFC.

   o&n=
bsp; Detailed the IPv6-per-channel prohibition paragraph which reflects


  &nbs=
p;   the discussion at the last IETF IPWAVE WG meeting.


   o&n=
bsp; Added section "Address Mapping -- Unicast".

   o&n=
bsp; Added the ".11 Trailer" to pictures of 802.11 frames.=



   o&n=
bsp; Added text about SNAP carrying the Ethertype.


   o&n=
bsp; New RSU definition allowing for it be both a Router and not


  &nbs=
p;   necessarily a Router some times.


   o&n=
bsp; Minor textual issues.


   Fro=
m 
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01 to =

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02


   o&n=
bsp; Replaced almost all occurences of 802.11p with 802.11-OCB, leaving


  &nbs=
p;   only when explanation of evolution was necessary.


   o&n=
bsp; Shortened by removing parameter details from a paragraph in the=



  &nbs=
p;   Introduction.


   o&n=
bsp; Moved a reference from Normative to Informative.


   o&n=
bsp; Added text in intro clarifying there is no handover spec at IEEE,


  &nbs=
p;   and that 1609.2 does provide security services.


   o&n=
bsp; Named the contents the fields of the EthernetII header (including


  &nbs=
p;   the Ethertype bitstring).


   o&n=
bsp; Improved relationship between two paragraphs describing the


  &nbs=
p;   increase of the Sequence Number in 802.11 header upon IP


  &nbs=
p;  <=
font face=3D"Calibri">fragmentation.








Petrescu, et al.&nb=
sp;       Expires February 18, 2018 &nbs=
p;            [Page =
27]


___________________=
_____________________


https:=
//tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-28


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   o&n=
bsp; Added brief clarification of "tracking".


   Fro=
m 
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-00 to =

https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01


   
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01


   o&n=
bsp; Introduced message exchange diagram illustrating differences


  &nbs=
p;   between 802.11 and 802.11 in OCB mode.


   o&n=
bsp; Introduced an appendix listing for information the set of 802.11


  &nbs=
p;   messages that may be transmitted in OCB mode.<=
/p>

   o&n=
bsp; Removed appendix sections "Privacy Requirements", "Auth=
entication


  &nbs=
p;   Requirements" and "Security Certificate Generation=
".


   o&n=
bsp; Removed appendix section "Non IP Communications".


   o&n=
bsp; Introductory phrase in the Security Considerations section.


   o&n=
bsp; Improved the definition of "OCB".


   o&n=
bsp; Introduced theoretical stacked layers about IPv6 and IEEE layers


  &nbs=
p;   including EPD.


   o&n=
bsp; Removed the appendix describing the details of prohibiting IPv6 on


  &nbs=
p;   certain channels relevant to 802.11-OCB.


   o&n=
bsp; Added a brief reference in the privacy text about a precise clause


  &nbs=
p;   in IEEE 1609.3 and .4.


   o&n=
bsp; Clarified the definition of a Road Side Unit.


   o&n=
bsp; Removed the discussion about security of WSA (because is non-IP).


   o&n=
bsp; Removed mentioning of the GeoNetworking discussion.


   o&n=
bsp; Moved references to scientific articles to a separate 'overview'


  &nbs=
p;   draft, and referred to it.


=
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-B.  Changes Needed on a software driver
 802.11a to become a


  &nbs=
p;          802.11-OCB driver<=
/font>


   The=
 802.11p amendment modifies both the 802.11 stack's physical and


   MAC=
 layers but all the induced modifications can be quite easily=



   obt=
ained by modifying an existing 802.11a ad-hoc stack.


   Con=
ditions for a 802.11a hardware to be 802.11-OCB compliant:









Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 28]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-29


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   o&n=
bsp; The chip must support the frequency bands on which the regulator


  &nbs=
p;   recommends the use of ITS communications, for example using =
IEEE


  &nbs=
p;   802.11-OCB layer, in France: 5875MHz to 5925MHz.


   o&n=
bsp; The chip must support the half-rate mode (the internal clock


  &nbs=
p;   should be able to be divided by two).


   o&n=
bsp; The chip transmit spectrum mask must be compliant to the "Transmi=
t


  &nbs=
p;   spectrum mask" from the IEEE 802.11p amendment (but exp=
erimental


  &nbs=
p;   environments tolerate otherwise).


   o&n=
bsp; The chip should be able to transmit up to 44.8 dBm when used by=



  &nbs=
p;   the US government in the United States, and up to 33 dBm in<=
/font>


  &nbs=
p;   Europe; other regional conditions apply.


   Cha=
nges needed on the network stack in OCB mode:


   o&n=
bsp; Physical layer:


  &nbs=
p;   *  The chip must use the Orthogonal Frequency Multiple =
Access


  &nbs=
p;      (OFDM) encoding mode.


  &nbs=
p;   *  The chip must be set in half-mode rate mode (the int=
ernal clock


  &nbs=
p;      frequency is divided by two).


  &nbs=
p;   *  The chip must use dedicated channels and should allo=
w the use


  &nbs=
p;      of higher emission powers.  This may =
require modifications to


  &nbs=
p;      the regulatory domains rules, if used by t=
he kernel to enforce


  &nbs=
p;      local specific restrictions.  Such mo=
difications must respect


  &nbs=
p;      the location-specific laws.<=
/p>

  &nbs=
p;   MAC layer:


  &nbs=
p;   *  All management frames (beacons, join, leave, and oth=
ers)


  &nbs=
p;      emission and reception must be disabled ex=
cept for frames of


  &nbs=
p;      subtype Action and Timing Advertisement (d=
efined below).


  &nbs=
p;   *  No encryption key or method must be used.


  &nbs=
p;   *  Packet emission and reception must be performed as i=
n ad-hoc


  &nbs=
p;      mode, using the wildcard BSSID (ff:ff:ff:f=
f:ff:ff).


  &nbs=
p;   *  The functions related to joining a BSS (Association =
Request/


  &nbs=
p;      Response) and for authentication (Authenti=
cation Request/Reply,


  &nbs=
p;      Challenge) are not called.

  &nbs=
p;   *  The beacon interval is always set to 0 (zero).








Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 29]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




  &nbs=
p;   *  Timing Advertisement frames, defined in the amendmen=
t, should


  &nbs=
p;      be supported.  The upper layer should=
 be able to trigger such


  &nbs=
p;      frames emission and to retrieve informatio=
n contained in


  &nbs=
p;      received Timing Advertisements.


=
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-C.  Design Considerations




   The=
 networks defined by 802.11-OCB are in many ways similar to other


   net=
works of the 802.11 family.  In theory, the encapsulation of IPv6


   ove=
r 802.11-OCB could be very similar to the operation of IPv6 over


   oth=
er networks of the 802.11 family.  However, the high mobility,<=
/span>


   str=
ong link asymetry and very short connection makes the 802.11-OCB


   lin=
k significantly different from other 802.11 networks.  Also, the


   aut=
omotive applications have specific requirements for reliability,


   sec=
urity and privacy, which further add to the particularity of the


   802=
.11-OCB link.


   Aut=
omotive networks require the unique representation of each of=



   the=
ir node.  Accordingly, a vehicle must be identified by at least=



   one=
 unique identifier.  The current specification at ETSI and at IEEE


   160=
9 identifies a vehicle by its MAC address uniquely obtained from


   the=
 802.11-OCB NIC.


   A M=
AC address uniquely obtained from a IEEE 802.11-OCB NIC


   imp=
licitely generates multiple vehicle IDs in case of multiple

   802=
.11-OCB NICs.  A mechanims to uniquely identify a vehicle


   irr=
espectively to the different NICs and/or technologies is required.


   The=
 dynamically changing topology, short connectivity, mobile

   tra=
nsmitter and receivers, different antenna heights, and many-to-


   man=
y communication types, make IEEE 802.11-OCB links significantly


   dif=
ferent from other IEEE 802.11 links.  Any IPv6 mechanism operating


   on =
IEEE 802.11-OCB link MUST support strong link asymetry, spatio-


   tem=
poral link quality, fast address resolution and transmission.=



   IEE=
E 802.11-OCB strongly differs from other 802.11 systems to operate


   out=
side of the context of a Basic Service Set.  This means in


   pra=
ctice that IEEE 802.11-OCB does not rely on a Base Station for all


   Bas=
ic Service Set management.  In particular, IEEE 802.11-OCB SHALL


   NOT=
 use beacons.  Any IPv6 mechanism requiring L2 services from IEEE


   802=
.11 beacons MUST support an alternative service.












Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 30]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-31


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   Cha=
nnel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST<=
/p>

   imp=
lement a mechanism for transmitter and receiver to converge to a


   com=
mon channel.


   Aut=
hentication not being possible, IPv6 over IEEE 802.11-OCB MUST


   imp=
lement an distributed mechanism to authenticate transmitters and


   rec=
eivers without the support of a DHCP server.


   Tim=
e synchronization not being available, IPv6 over IEEE 802.11-OCB


   MUS=
T implement a higher layer mechanism for time synchronization=



   bet=
ween transmitters and receivers without the support of a NTP<=
/p>

   ser=
ver.


   The=
 IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB


   MUS=
T disable management mechanisms requesting acknowledgements or


   rep=
lies.


   The=
 IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE


   802=
.11-OCB MUST implement fast IPv6 mobility management mechanisms.


   The=
re are considerations for 2 or more IEEE 802.11-OCB interface=



   car=
ds per vehicle.  For each vehicle taking part in road traffic, one


   IEE=
E 802.11-OCB interface card could be fully allocated for Non IP


   saf=
ety-critical communication.  Any other IEEE 802.11-OCB may be used


   for=
 other type of traffic.


   The=
 mode of operation of these other wireless interfaces is not<=
/p>

   cle=
arly defined yet.  One possibility is to consider each card as an


   ind=
ependent network interface, with a specific MAC Address and a set


   of =
IPv6 addresses.  Another possibility is to consider the set of<=
/span>


   the=
se wireless interfaces as a single network interface (not


   inc=
luding the IEEE 802.11-OCB interface used by Non IP safety

   cri=
tical communications).  This will require specific logic to


   ens=
ure, for example, that packets meant for a vehicle in front are


   act=
ually sent by the radio in the front, or that multiple copies of


   the=
 same packet received by multiple interfaces are treated as a=



   sin=
gle packet.  Treating each wireless interface as a separate


   net=
work interface pushes such issues to the application layer.

   The=
 privacy requirements of [] imply that if these multiple


   int=
erfaces are represented by many network interface, a single

   ren=
umbering event SHALL cause renumbering of all these interfaces.


   If =
one MAC changed and another stayed constant, external observers


   wou=
ld be able to correlate old and new values, and the privacy

   ben=
efits of randomization would be lost.








Petrescu, et al.=
        Expires February 18, 2018 &=
nbsp;            [Pa=
ge 31]


________________=
________________________


htt=
ps://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32


Internet-Draft&n=
bsp;            IPv6=
-over-80211ocb          &=
nbsp;     August 2017




   The=
 privacy requirements of Non IP safety-critical communications


   imp=
ly that if a change of pseudonyme occurs, renumbering of all other


   int=
erfaces SHALL also occur.


   Whe=
n designing the IPv6 over 802.11-OCB address mapping, we will=



   ass=
ume that the MAC Addresses will change during well defined

   &qu=
ot;renumbering events".  The 48 bits randomized MAC addresses wil=
l have


   the=
 following characteristics:


   o&n=
bsp; Bit "Local/Global" set to "locally admninistered".=



   o&n=
bsp; Bit "Unicast/Multicast" set to "Unicast".


   o&n=
bsp; 46 remaining bits set to a random value, using a random number<=
/span>


  &nbs=
p;   generator that meets the requirements of [https://tools.ietf.org/html/rfc4086].


   The=
 way to meet the randomization requirements is to retain 46 bits


   fro=
m the output of a strong hash function, such as SHA256, taking as


   inp=
ut a 256 bit local secret, the "nominal" MAC Address of the


   int=
erface, and a representation of the date and time of the


   ren=
umbering event.


=
https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendi=
x-D.  IEEE 802.11 Messages Transmitted
 in OCB mode




   For=
 information, at the time of writing, this is the list of IEEE


   802=
.11 messages that may be transmitted in OCB mode, i.e. when

   dot=
11OCBActivated is true in a STA:


   o&n=
bsp; The STA may send management frames of subtype Action and, if the


  &nbs=
p;   STA maintains a TSF Timer, subtype Timing Advertisement;


   o&n=
bsp; The STA may send control frames, except those of subtype PS-Poll,


  &nbs=
p;   CF-End, and CF-End plus CFAck;


   o&n=
bsp; The STA may send data frames of subtype Data, Null, QoS Data, and


  &nbs=
p;   QoS Null.


Authors' Address=
es











--_000_D5CA344D22C206sgundaveciscocom_--


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To: Sri Gundavelli 
References: 
Cc: its@ietf.org
From: Alexandre Petrescu 
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Date: Wed, 30 Aug 2017 16:33:10 +0200
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Subject: Re: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
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Sri,

I want to let you know I have today finished to read the entire set of
comments.  I will try to address them soon.

Alex

Le 28/08/2017 à 05:00, Sri Gundavelli (sgundave) a écrit :
> 
> Attached is my review feedback.
> 
> In general there is lot of good information in the document. But,
> there are also few areas where additional clarifications will greatly
> help.
> 
> 1.) Its not clear, if the document makes any assumption on the
> operating environment/communication profile. There is not much
> discussion on that aspect; For example, Is it always a one-hop
> communication between RSU and OBU where the 802.11-OCB link?  So, is
> the use of IPv6 only in that context of 1-hop communication?
> 
> 2.) There is also no discussion on how these links get formed in 
> vehicular environment and when they are attached/detached.
> 
> 3.) How do nodes discover each other?  How does ND resolution work?
> Are these messages received by a multiple RSU’s, or a single RSU?
> Whats the implication of that. Note that you don’t have that issue in
> 802.11, given the association to an access point, which in turn maps
> the links to a VLAN/subnet.
> 
> 4.) What happens as a vehicle moves between RSU’s, how does it impact
>  address configuration?   Is DHCPv6 based address configuration
> relevant here?
> 
> 
> Please see inline for additional comments.
> 
[...]
> 
> Transmission of IPv6 Packets over IEEE 802.11 Networks in mode
> Outside
> 
> 
> 
> 
> 
> the Context of a Basic Service Set (IPv6-over-80211ocb)
> 
> 
> 
> 
> 
> draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
> 
> 
> 
> 
> [Sri] May be change to, “..in mode .." —> “..operating in mode ..”?
> 
> 
> 
> Abstract
> 
> In order to transmit IPv6 packets on IEEE 802.11 networks run
> outside the context of a basic service set (OCB, earlier "802.11p")
> there is a need to define a few parameters such as the recommended
> Maximum Transmission Unit size, the header format preceding the IPv6
> header, the Type value within it, and others.  This document
> describes these parameters for IPv6 and IEEE 802.11 OCB networks; it
> portrays the layering of IPv6 on 802.11 OCB similarly to other known
> 802.11 and Ethernet layers - by using an Ethernet Adaptation Layer.
> 
> [Sri] Is it “recommended MTU size", or "supported MTU size on the
> 802.11 OCB link?
> 
> 
> 
> In addition, the document attempts to list what is different in 
> 802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n 
> layers, layers over which IPv6 protocols operates without issues. 
> Most notably, the operation outside the context of a BSS (OCB) has 
> impact on IPv6 handover behaviour and on IPv6 security.
> 
> [Sri] Minor comment. May be instead of using the “layer” terminology,
>  you may want to present this as IPv6 support on "802.11 OCB" links.
> 
> 
> An example of an IPv6 packet captured while transmitted over an IEEE 
> 802.11 OCB link (802.11p) is given.
> 
> [Sri] Last paragraph can be ommitted in my view. That’s too much of 
> detail for Abstract.
> 
> 
> Status of This Memo
> 
> This Internet-Draft is submitted in full conformance with the 
> provisions ofBCP 78   andBCP 79
> .
> 
> Internet-Drafts are working documents of the Internet Engineering 
> Task Force (IETF).  Note that other groups may also distribute
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 1]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> working documents as Internet-Drafts.  The list of current Internet- 
> Drafts is athttp://datatracker.ietf.org/drafts/current/.
> 
> Internet-Drafts are draft documents valid for a maximum of six
> months and may be updated, replaced, or obsoleted by other documents
> at any time.  It is inappropriate to use Internet-Drafts as
> reference material or to cite them other than as "work in progress."
> 
> This Internet-Draft will expire on February 18, 2018.
> 
> Copyright Notice
> 
> Copyright (c) 2017 IETF Trust and the persons identified as the 
> document authors.  All rights reserved.
> 
> This document is subject toBCP 78 
> and the IETF Trust's Legal Provisions Relating to IETF Documents 
> (http://trustee.ietf.org/license-info) in effect on the date of 
> publication of this document.  Please review these documents 
> carefully, as they describe your rights and restrictions with
> respect to this document.  Code Components extracted from this
> document must include Simplified BSD License text as described in
> Section 4.e of the Trust Legal Provisions and are provided without
> warranty as described in the Simplified BSD License.
> 
> Table of Contents
> 
> 1 
> .
> Introduction  . . . . . . . . . . . . . . . . . . . . . . . .3 
> 
>
> 
2
> .
> Terminology . . . . . . . . . . . . . . . . . . . . . . . . .5 
> 
>
> 
3.  Communication Scenarios where IEEE 802.11 OCB Links are Used    6
> 4 
> .
> Aspects introduced by the OCB mode to 802.11  . . . . . . . .6 
> 
>
> 
5
> .
> Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . .10 
> 
>
> 
5.1
> .
> Maximum Transmission Unit (MTU) . . . . . . . . . . . . .10 
> 
>
> 
5.2
> .
> Frame Format  . . . . . . . . . . . . . . . . . . . . . .11 
> 
>
> 
5.2.1
> .
> Ethernet Adaptation Layer . . . . . . . . . . . . . .12 
> 
>
> 
5.3
> .
> Link-Local Addresses  . . . . . . . . . . . . . . . . . .13 
> 
>
> 
5.4
> .
> Address Mapping . . . . . . . . . . . . . . . . . . . . .14 
> 
>
> 
5.4.1
> .
> Address Mapping -- Unicast  . . . . . . . . . . . . .14 
> 
>
> 
5.4.2
> .
> Address Mapping -- Multicast  . . . . . . . . . . . .14 
> 
>
> 
5.5
> .
> Stateless Autoconfiguration . . . . . . . . . . . . . . .15 
> 
>
> 
5.6
> .
> Subnet Structure  . . . . . . . . . . . . . . . . . . . .16 
> 
>
> 
6
> .
> Example IPv6 Packet captured over a IEEE 802.11-OCB link  . .16 
> 
>
> 
6.1
> .
> Capture in Monitor Mode . . . . . . . . . . . . . . . . .17 
> 
>
> 
6.2
> .
> Capture in Normal Mode  . . . . . . . . . . . . . . . . .19 
> 
>
> 
7
> .
> Security Considerations . . . . . . . . . . . . . . . . . . .21 
> 
>
> 
8
> .
> IANA Considerations . . . . . . . . . . . . . . . . . . . . .22 
> 
>
> 
9
> .
> Contributors  . . . . . . . . . . . . . . . . . . . . . . . .22 
> 
>
> 
10
> .
> Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .22 
> 
>
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 2]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> 11 
> .
> References  . . . . . . . . . . . . . . . . . . . . . . . . .23 
> 
>
> 
11.1
> .
> Normative References . . . . . . . . . . . . . . . . . .23 
> 
>
> 
11.2
> .
> Informative References . . . . . . . . . . . . . . . . .24 
> 
>
> 
Appendix A
> .
> ChangeLog  . . . . . . . . . . . . . . . . . . . . .26 
> 
>
> 
Appendix B
> .
> Changes Needed on a software driver 802.11a to become a
> 802.11-OCB driver . . .28 
> 
>
> 
Appendix C
> .
> Design Considerations  . . . . . . . . . . . . . . .30 
> 
>
> 
C.1
> .
> Vehicle ID  . . . . . . . . . . . . . . . . . . . . . . .30 
> 
>
> 
C.2
> .
> Reliability Requirements  . . . . . . . . . . . . . . . .30 
> 
>
> 
C.3
> .
> Multiple interfaces . . . . . . . . . . . . . . . . . . .31 
> 
>
> 
C.4
> .
> MAC Address Generation  . . . . . . . . . . . . . . . . .32 
> 
>
> 
Appendix D
> .
> IEEE 802.11 Messages Transmitted in OCB mode . . . .32 
> 
>
> 
Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .32
> 
>
> 
> 
> 1 
> .
>
> 
Introduction
> 
> 
> 
> This document describes the transmission of IPv6 packets on IEEE Std 
> 802.11 OCB networks (earlier known as 802.11p).
> 
> 
> [Sri] Please add a reference to the IEEE specification that defines
> the OCB mode.
> 
> 
> 
> This involves the layering of IPv6 networking on top of the IEEE
> 802.11 MAC layer (with an LLC layer).  Compared to running IPv6 over
> the Ethernet MAC layer, there is no modification required to the
> standards: IPv6 works fine directly over 802.11 OCB too (with an LLC
> layer).
> 
> The term "802.11p" is an earlier definition.  As of year 2012, the 
> behaviour of "802.11p" networks has been rolled in the document IEEE 
> Std 802.11-2012.  In this document the term 802.11p disappears. 
> Instead, each 802.11p feature is conditioned by a flag in the 
> Management Information Base.  That flag is named "OCBActivated". 
> Whenever OCBActivated is set to true the feature it relates to 
> represents an earlier 802.11p feature.  For example, an 802.11 
> STAtion operating outside the context of a basic service set has the 
> OCBActivated flag set.  Such a station, when it has the flag set, it 
> uses a BSS identifier equal to ff:ff:ff:ff:ff:ff.
> 
> In the following text we use the term "802.11p" to mean 802.11-2012 
> OCB.
> 
> The IPv6 network layer operates on 802.11 OCB in the same manner as 
> it operates on 802.11 WiFi, with a few particular exceptions.  The 
> IPv6 network layer operates on WiFi by involving an Ethernet 
> Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers 
> to Ethernet II headers.  The operation of IP on Ethernet is
> described in [RFC1042 ] and
> [RFC2464 ].  The situation of
> IPv6 networking layer on Ethernet Adaptation Layer is illustrated
> below:
> 
> 
> 
> 
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 3]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |                 IPv6
> | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |       Ethernet
> Adaptation Layer       | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> 802.11 WiFi MAC           | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |             802.11 WiFi
> PHY           | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> 
> (in the above figure, a WiFi profile is represented; this is used 
> also for OCB profile.)
> 
> A more theoretical and detailed view of layer stacking, and 
> interfaces between the IP layer and 802.11 OCB layers, is
> illustrated below.  The IP layer operates on top of the EtherType
> Protocol Discrimination (EPD); this Discrimination layer is described
> in IEEE Std 802.3-2012; the interface between IPv6 and EPD is the
> LLC_SAP (Link Layer Control Service Accesss Point).
> 
> 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |                 IPv6
> | +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+ {   LLC_SAP  }
> 802.11 OCB +-+-+-+-+-+-{            }+-+-+-+-+-+-+-+  Boundary |
> EPD          |       |     | |                         | MLME  |
> | +-+-+-{  MAC_SAP   }+-+-+-|  MLME_SAP   | |      MAC Sublayer
> |       |     |  802.11 OCB |     and ch. coord.      |       | SME |
> Services +-+-+-{   PHY_SAP  }+-+-+-+-+-+-+-|     | |
> | PLME  |     | |            PHY Layer    |   PLME_SAP  | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> 
> In addition to the description of interface between IP and MAC using 
> "Ethernet Adaptation Layer" and "Ethernet Protocol Discrimination 
> (EPD)" it is worth mentioning that SNAP [RFC1042
> ] is used to carry the IPv6
> Ethertype.
> 
> However, there may be some deployment considerations helping
> optimize the performances of running IPv6 over 802.11-OCB (e.g. in
> the case of handovers between 802.11 OCB-enabled access routers, or
> the consideration of using the IP security layer [RFC4301
> ]).
> 
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 4]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> There are currently no specifications for handover between OCB links 
> since these are currently specified as LLC-1 links (i.e. 
> connectionless).  Any handovers must be performed above the Data
> Link Layer.  Also, while there is no encryption applied below the
> network layer using 802.11p, 1609.2 [ieee1609.2 
> ]
> does provide security services for applications to use so that there
> can easily be data security over the air without invoking IPsec.
> 
> We briefly introduce the vehicular communication scenarios where
> IEEE 802.11-OCB links are used.
> 
> 
> [Sri] I have not seen much discussion on the link / communication 
> assumptions.
> 
> 
> 
> This is followed by a description of differences in specification
> terms, between 802.11 OCB and 802.11a/b/g/n (and the same differences
> expressed in terms of requirements to software implementation are
> listed inAppendix B 
> .)
>
>  The document then concentrates on the parameters of layering IP
> over 802.11 OCB as over Ethernet: value of MTU, the contents of
> Frame Format, the rules for forming Interface Identifiers, the
> mechanism for Address Mapping and for State-less Address
> Auto-configuration. These are precisely the same as IPv6 over
> Ethernet [RFC2464 ].
> 
> As an example, these characteristics of layering IPv6 straight over 
> LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet 
> captured over a 802.11 OCB link; this is described in the section 
> Section 6 
> .
>
>  A couple of points can be considered as different, although they
> are not required in order to have a working implementation of
> IPv6-over- 802.11-OCB.  These points are consequences of the OCB
> operation which is particular to 802.11 OCB (Outside the Context of a
> BSS).  First, the handovers between OCB links need specific behaviour
> for IP Router Advertisements, or otherwise 802.11 OCB's Time
> Advertisement, or of higher layer messages such as the 'Basic Safety
> Message' (in the US) or the 'Cooperative Awareness Message' (in the
> EU) or the 'WAVE Routing Advertisement'; second, the IP security
> mechanisms are necessary, since OCB means that 802.11 is stripped of
> all 802.11 link-layer security; a small additional security aspect
> which is shared between 802.11 OCB and other 802.11 links is the
> privacy concerns related to the address formation mechanisms.
> 
> In the published literature, many documents describe aspects related 
> to running IPv6 over 802.11 OCB: 
> [I-D.jeong-ipwave-vehicular-networking-survey 
> ].
>
> 
> 
> 2 
> .
>
> 
Terminology
> 
> 
> 
> The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 
> "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 
> document are to be interpreted as described inRFC 2119
>   [RFC2119
> ].
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 5]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> RSU: Road Side Unit.  A computer equipped with at least one IEEE 
> 802.11 interface operated in OCB mode.  This definition applies to 
> this document.  An RSU may be connected to the Internet, and may be 
> equipped with additional wired or wireless network interfaces
> running IP.  An RSU MAY be an IP Router.
> 
> 
> [Sri] RSU can be compared to an 802.11 access point; Or, WTP as
> defined in CAPWAP specification, RFC5415.
> 
> 
> Perhaps. rephrase as below?:
> 
> 
> "RSU: Road Side Unit. Its a wireless termination point (WTP), as
> defined in RFC5415 with one key difference, where the wireless
> physical and the mac layer is configured to operate in 802.11 OCB
> mode.  The RSU communicates with the On board Unit (OBU) in the
> vehicle over 802.11 wireless link operating in OCB mode.”
> 
> 
> 
> ** Also, since you are defining the RSU term, should you also not
> define OBU (On board Unit) in the vehicle which is the entity on the
> other end of the link? “RSU ----802.11-OCB——OBU” ? May be introduce
> the OCB definition separately, just as you did with RSU, and show the
>  communication link as 802.11-OCB.
> 
> 
> 
> OCB: outside the context of a basic service set (BSS): A mode of 
> operation in which a STA is not a member of a BSS and does not 
> utilize IEEE Std 802.11 authentication, association, or data 
> confidentiality.
> 
> 802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is 
> flagged by "dot11OCBActivated".  This means: IEEE 802.11e for
> quality of service; 802.11j-2004 for half-clocked operations; and
> (what was known earlier as) 802.11p for operation in the 5.9 GHz band
> and in mode OCB.
> 
> 
> [Sri] The text starting with. “This means” is not clear to me. Does
> it 802.11e is supported with 802.11OCB mode. Please clarify
> 
> 
> 
> 3 
> .
>
> 
Communication Scenarios where IEEE 802.11 OCB Links are Used
> 
> 
> 
> The IEEE 802.11 OCB Networks are used for vehicular communications, 
> as 'Wireless Access in Vehicular Environments'.  The IP
> communication scenarios for these environments have been described in
> several documents, among which we refer the reader to one recently
> updated [I-D.petrescu-its-scenarios-reqs 
> ],
> about scenarios and requirements for IP in Intelligent Transportation
> Systems.
> 
> 
> [Sri] You can do bit more justice to this section.
> 
> Explain the link model. “STA ----802.11-OCB——STA”. Then talk about
> the applicability in Vehicular networks, with STA's as RSU and OCB.
> 
> You may also want to talk about, how links get formed/terminated; how
>  nodes peer/discover and how mobility works ..etc. While 802.11-OCB
> is clearly specified and the use of IPv6 over such link is also not 
> radically new, but the operating environment which is vehicular
> brings many new things. That description is not present any where.
> 
> 
> 4 
> .
>
> 
Aspects introduced by the OCB mode to 802.11
> 
> 
> 
> In the IEEE 802.11 OCB mode, all nodes in the wireless range can 
> directly communicate with each other without authentication/ 
> association procedures.  Briefly, the IEEE 802.11 OCB mode has the 
> following properties:
> 
> 
> 
> [Sri] Can you add some text on how nodes (ST1 and STA2) discover each
>  other on such links supporting 802.11 OCB mode.
> 
> o  The use by each node of a 'wildcard' BSSID (i.e., each bit of the 
> BSSID is set to 1)
> 
> o  No IEEE 802.11 Beacon frames transmitted
> 
> o  No authentication required
> 
> o  No association needed
> 
> o  No encryption provided
> 
> 
> [Sri] Can you clarify what you mean when you say “No xxx required” /
> “No xxx needed” for the above capabilities.  What does “needed” or 
> “required” mean? Does it mean, “Authentication", “Association" and 
> “Encryption” is optional on this link, or that its not supported on 
> 802.11 OCB links.
> 
> 
> o  Flag dot11OCBActivated set to true
> 
> The following message exchange diagram illustrates a comparison 
> between traditional 802.11 and 802.11 in OCB mode.  The 'Data'
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 6]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> messages can be IP messages such as the messages used in Stateless
> or Stateful Address Auto-Configuration, or other IP messages.
> 
> 
> 
> [Sri] Lets separatethe discussion on IP Address configuration using 
> SLAAC/DHCP on such links from the above description. The Data packets
>  here can be application packets such as HTTP or other packets. May
> be additional discussion is needed on the IP address configuration on
>  802.11-OCB links.
> 
> 
> 
> Other 802.11 management and control frames (non IP) may be
> transmitted, as specified in the 802.11 standard.  For information,
> the names of these messages as currently specified by the 802.11
> standard are listed inAppendix D 
> .
>
> 
> 
> 
> 
> 
> 
> STA                    AP              STA1                   STA2 |
> |               |                      | |<------ Beacon -------|
> |<------ Data -------->| |                      |               |
> | |---- Probe Req. ----->|               |<------ Data -------->| 
> |<--- Probe Res. ------|               |                      | |
> |               |<------ Data -------->| |---- Auth Req. ------>|
> |                      | |<--- Auth Res. -------|
> |<------ Data -------->| |                      |               |
> | |---- Asso Req. ------>|               |<------ Data -------->| 
> |<--- Asso Res. -------|               |                      | |
> |               |<------ Data -------->| |<------ Data -------->|
> |                      | |<------ Data -------->|
> |<------ Data -------->|
> 
> (a) 802.11 Infrastructure mode         (b) 802.11 OCB mode
> 
> 
> The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010 
> [ieee802.11p-2010 
> ]
> as an amendment to IEEE Std 802.11 (TM) -2007, titled "Amendment 6:
> Wireless Access in Vehicular Environments". Since then, this
> amendment has been included in IEEE 802.11(TM)-2012 [ieee802.11-2012
>  
> ],
> titled "IEEE Standard for Information technology-- Telecommunications
> and information exchange between systems Local and metropolitan area
> networks--Specific requirements Part 11: Wireless LAN Medium Access
> Control (MAC) and Physical Layer (PHY) Specifications"; the
> modifications are diffused throughout various sections (e.g. the Time
> Advertisement message described in the earlier 802.11 (TM) p
> amendment is now described in section 'Frame formats', and the
> operation outside the context of a BSS described in section 'MLME').
> 
> In document 802.11-2012, specifically anything referring 
> "OCBActivated", or "outside the context of a basic service set" is 
> actually referring to the 802.11p aspects introduced to 802.11.
> Note that in earlier 802.11p documents the term "OCBEnabled" was
> used instead of te current "OCBActivated".
> 
> 
> 
> 
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> 
> 
> In order to delineate the aspects introduced by 802.11 OCB to
> 802.11, we refer to the earlier [ieee802.11p-2010 
> ].
> The amendment is concerned with vehicular communications, where the
> wireless link is similar to that of Wireless LAN (using a PHY layer
> specified by 802.11a/b/g/n), but which needs to cope with the high
> mobility factor inherent in scenarios of communications between
> moving vehicles, and between vehicles and fixed infrastructure
> deployed along roads. While 'p' is a letter just like 'a, b, g' and
> 'n' are, 'p' is concerned more with MAC modifications, and a little
> with PHY modifications; the others are mainly about PHY
> modifications.  It is possible in practice to combine a 'p' MAC with
> an 'a' PHY by operating outside the context of a BSS with OFDM at
> 5.4GHz.
> 
> The 802.11 OCB links are specified to be compatible as much as 
> possible with the behaviour of 802.11a/b/g/n and future generation 
> IEEE WLAN links.* From the IP perspective, an 802.11 OCB MAC layer
> offers practically the same interface to IP as the WiFi and Ethernet
> layers do (802.11a/b/g/n and 802.3).*
> 
> 
> [Sri] A packet sent from a vehicle’s OBU is received by a single RSU,
> or multiple RSU’s? How does the link-layer resolution happen?
> 
> 
> To support this similarity statement (IPv6 is layered on top of LLC 
> on top of 802.11 OCB similarly as on top of LLC on top of 
> 802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to 
> analyze the differences between 802.11 OCB and 802.11
> specifications. Whereas the 802.11p amendment specifies relatively
> complex and numerous changes to the MAC layer (and very little to the
> PHY layer), we note there are only a few characteristics which may be
> important for an implementation transmitting IPv6 packets on 802.11
> OCB links.
> 
> In the list below, the only 802.11 OCB fundamental points which 
> influence IPv6 are the OCB operation and the 12Mbit/s maximum which 
> may be afforded by the IPv6 applications.
> 
> 
> [Sri] I am really not sure how link throughput (12Mbps) relates to
> "IPv6 support on OCB links".
> 
> 
> 
> o  Operation Outside the Context of a BSS (OCB): the (earlier 
> 802.11p) 802.11-OCB links are operated without a Basic Service Set 
> (BSS).  This means that the frames IEEE 802.11 Beacon, Association 
> Request/Response, Authentication Request/Response, and similar, are
> not used.  The used identifier of BSS (BSSID) has a hexadecimal value
> always 0xffffffffffff (48 '1' bits, represented as MAC address
> ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' BSSID), as opposed to
> an arbitrary BSSID value set by administrator (e.g.
> 'My-Home-AccessPoint').  The OCB operation - namely the lack of
> beacon-based scanning and lack of authentication - has a potentially
> strong impact on the use of the Mobile IPv6 protocol [RFC6275
> ] and on the protocols for IP
> layer security [RFC4301 ].
> 
> 
> [Sri] The document till now has been arguing heavily on how IPv6 
> operates so naturally on these links and now I see discussion on
> “Impact to a high-level protocol such as MIPv6”. You may want to fix
> the earlier text. In any case, the absence of link-layer security
> practically impacts every application, not just MIPv6. Also, MIPv6
> does not make any assumptions on the link-layer security. Also, the
> the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes the messages readable by
> all other RSU’s in proximity. I think the discussion on the nature of
> the link, who all see’s the messages.. how L2 addresses are resolved
> is not explained clearly.
> 
> 
> 
> 
> o  Timing Advertisement: is a new message defined in 802.11-OCB, 
> which does not exist in 802.11a/b/g/n.  This message is used by
> 
> 
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> 
> 
> stations to inform other stations about the value of time.  It is 
> similar to the time as delivered by a GNSS system (Galileo, GPS, ...)
> or by a cellular system.  This message is optional for 
> implementation.*At the date of writing, an experienced reviewer
> considers that currently no field testing has used this message.
> Another implementor considers this feature implemented in an initial
> manner. In the future, it is speculated that this message may be
> useful for very simple devices which may not have their own hardware
> source of time (Galileo, GPS, cellular network), or by vehicular
> devices situated in areas not covered by such network (in tunnels,
> underground, outdoors but shaded by foliage or buildings, in remote
> areas, etc.) *
> 
> 
> [Sri] The first part explaining Timing Advertisement messages is
> great, but the rest of the commentary is unnecessary and not needed.
> We don’t speculate the protocol adoption success in IETF
> specifications, or about the experience level of the “reviewer" :)
> 
> 
> 
> o  Frequency range: this is a characteristic of the PHY layer, with 
> almost no impact to the interface between MAC and IP.  However, it is
> worth considering that the frequency range is regulated by a regional
> authority (ARCEP, ETSI, FCC, etc.); as part of the regulation
> process, specific applications are associated with specific frequency
> ranges.  In the case of 802.11-OCB, the regulator associates a set of
> frequency ranges, or slots within a band, to the use of applications
> of vehicular communications, in a band known as "5.9GHz".  This band
> is "5.9GHz" which is different from the bands "2.4GHz" or "5GHz" used
> by Wireless LAN.  However, as with Wireless LAN, the operation of
> 802.11-OCB in "5.9GHz" bands is exempt from owning a license in EU
> (in US the 5.9GHz is a licensed band of spectrum; for the the fixed
> infrastructure an explicit FCC autorization is required; for an
> onboard device a 'licensed-by-rule' concept applies: rule
> certification conformity is required); however technical conditions
> are different than those of the bands "2.4GHz" or "5GHz".  On one
> hand, the allowed power levels, and implicitly the maximum allowed
> distance between vehicles, is of 33dBm for 802.11-OCB (in Europe),
> compared to 20 dBm for Wireless LAN 802.11a/b/g/n; this leads to a
> maximum distance of approximately 1km, compared to approximately 50m.
> On the other hand, specific conditions related to congestion 
> avoidance, jamming avoidance, and radar detection are imposed on the
> use of DSRC (in US) and on the use of frequencies for Intelligent
> Transportation Systems (in EU), compared to Wireless LAN
> (802.11a/b/g/n).
> 
> o  Prohibition of IPv6 on some channels relevant for IEEE
> 802.11-OCB, as opposed to IPv6 not being prohibited on any channel on
> which 802.11a/b/g/n runs:
> 
> *  Some channels are reserved for safety communications; the IPv6 
> packets should not be sent on these channels.
> 
> 
> 
> 
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> 
> 
> *  At the time of writing, the prohibition is explicit at higher 
> layer protocols providing services to the application; these higher
> layer protocols are specified in IEEE 1609 documents.
> 
> *  National or regional specifications and regulations specify the 
> use of different channels; these regulations must be followed.
> 
> o  'Half-rate' encoding: as the frequency range, this parameter is 
> related to PHY, and thus has not much impact on the interface between
> the IP layer and the MAC layer.
> 
> o  In vehicular communications using 802.11-OCB links, there are 
> strong privacy requirements with respect to addressing.  While the 
> 802.11-OCB standard does not specify anything in particular with 
> respect to MAC addresses, in these settings there exists a strong 
> need for dynamic change of these addresses (as opposed to the non- 
> vehicular settings - real wall protection - where fixed MAC addresses
> do not currently pose some privacy risks).  This is further described
> in sectionSection 7 
> .
> A relevant function is described in IEEE 1609.3-2016 [ieee1609.3 
> ],
> clause 5.5.1 and IEEE 1609.4-2016 [ieee1609.4 
> ],
> clause 6.7.
> 
> 
> Other aspects particular to 802.11-OCB which are also particular to 
> 802.11 (e.g. the 'hidden node' operation) may have an influence on 
> the use of transmission of IPv6 packets on 802.11-OCB networks.*The
> subnet structure which may be assumed in 802.11-OCB networks is 
> strongly influenced by the mobility of vehicles.*
> 
> 
> [Sri] Per my earlier comment, the link model, addressing ..etc needs
> to be explained in more detail. It is not clear what exactly the
> “subnet structure” that is assumed in 802.11-OCB.
> 
> 
> 5 
> .
>
> 
Layering of IPv6 over 802.11-OCB as over Ethernet
> 
> 
> 
> 5.1 
> .
>
> 
Maximum Transmission Unit (MTU)
> 
> 
> 
> The default MTU for IP packets on 802.11-OCB is 1500 octets.  It is 
> the same value as IPv6 packets on Ethernet links, as specified in 
> [RFC2464 ].  This value of the
> MTU respects the recommendation that every link in the Internet must
> have a minimum MTU of 1280 octets (stated in [RFC2460
> ], and the recommendations
> therein, especially with respect to fragmentation).  If IPv6 packets
> of size larger than 1500 bytes are sent on an 802.11-OCB interface
> card then the IP stack will fragment.  In case there are IP
> fragments, the field "Sequence number" of the 802.11 Data header
> containing the IP fragment field is increased.
> 
> Non-IP packets such as WAVE Short Message Protocol (WSMP) can be 
> delivered on 802.11-OCB links.  Specifications of these packets are 
> out of scope of this document, and do not impose any limit on the
> MTU size, allowing an arbitrary number of 'containers'.  Non-IP
> packets such as ETSI 'geonet' packets have an MTU of 1492 bytes.
> 
> 
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> 
> 
> The Equivalent Transmit Time on Channel is a concept that may be
> used as an alternative to the MTU concept.  A rate of transmission
> may be specified as well.  The ETTC, rate and MTU may be in direct 
> relationship.
> 
> [Sri] The last paragraph needs some additional context. Did
> 802.11-OCB introduce ETTC concept?
> 
> 
> 
> 
> 5.2 
> .
>
> 
Frame Format
> 
> 
> 
> IP packets are transmitted over 802.11-OCB as standard Ethernet 
> packets.  As with all 802.11 frames, an Ethernet adaptation layer is 
> used with 802.11-OCB as well.  This Ethernet Adaptation Layer 
> performing 802.11-to-Ethernet is described inSection 5.2.1 
> .
> The Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal
> 86DD, or otherwise #86DD).
> 
> The Frame format for transmitting IPv6 on 802.11-OCB networks is the 
> same as transmitting IPv6 on Ethernet networks, and is described in 
> section 3 of [RFC2464]
> .  The frame format
> for transmitting IPv6 packets over Ethernet is illustrated below:
> 
> 
> 0                   1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |          Destination          | 
> +-                             -+ |            Ethernet           | 
> +-                             -+ |            Address            | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |             Source            | 
> +-                             -+ |            Ethernet           | 
> +-                             -+ |            Address            | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1| 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |             IPv6              | 
> +-                             -+ |            header             | 
> +-                             -+ |             and               | 
> +-                             -+ /            payload ...        / 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (Each tic mark represents one
> bit.)
> 
> 
> 
> 
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> 
> 
> Ethernet II Fields:
> 
> Destination Ethernet Address the MAC destination address.
> 
> Source Ethernet Address the MAC source address.
> 
> 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 binary representation of the
> EtherType value 0x86DD.
> 
> IPv6 header and payload the IPv6 packet containing IPv6 header and
> payload.
> 
> 
> 5.2.1 
> .
>
> 
Ethernet Adaptation Layer
> 
> 
> 
> In general, an 'adaptation' layer is inserted between a MAC layer
> and the Networking layer.  This is used to transform some parameters 
> between their form expected by the IP stack and the form provided by 
> the MAC layer.  For example, an 802.15.4 adaptation layer may
> perform fragmentation and reassembly operations on a MAC whose
> maximum Packet Data Unit size is smaller than the minimum MTU
> recognized by the IPv6 Networking layer.  Other examples involve
> link-layer address transformation, packet header insertion/removal,
> and so on.
> 
> An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 
> Networking layer as a more traditional Ethernet layer.  At
> reception, this layer takes as input the IEEE 802.11 Data Header and
> the Logical-Link Layer Control Header and produces an Ethernet II
> Header. At sending, the reverse operation is performed.
> 
> 
> +--------------------+------------+-------------+---------+-----------+
>
> 
| 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer|
> +--------------------+------------+-------------+---------+-----------+
>
> 
\                               /                         \         /
> -----------------------------                             -------- 
> ^---------------------------------------------/ | 802.11-to-Ethernet
> Adaptation Layer | v +---------------------+-------------+---------+ 
> | Ethernet II Header  | IPv6 Header | Payload | 
> +---------------------+-------------+---------+
> 
> 
> 
> 
> 
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> 
> 
> The Receiver and Transmitter Address fields in the 802.11 Data
> Header contain the same values as the Destination and the Source
> Address fields in the Ethernet II Header, respectively.  The value of
> the Type field in the LLC Header is the same as the value of the
> Type field in the Ethernet II Header.
> 
> The ".11 Trailer" contains solely a 4-byte Frame Check Sequence.
> 
> The Ethernet Adaptation Layer performs operations in relation to IP 
> fragmentation and MTU.  One of these operations is briefly described 
> in sectionSection 5.1 
> .
>
>  In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11 
> Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in 
> the following figure:
> 
> 
> +--------------------+-------------+-------------+---------+-----------+
>
> 
| 802.11 Data Header | LLC Header  | IPv6 Header | Payload |.11 Trailer|
> +--------------------+-------------+-------------+---------+-----------+
>
>  or
> 
> +--------------------+-------------+-------------+---------+-----------+
>
> 
| 802.11 QoS Data Hdr| LLC Header  | IPv6 Header | Payload |.11 Trailer|
> +--------------------+-------------+-------------+---------+-----------+
>
> 
> 
> The distinction between the two formats is given by the value of the 
> field "Type/Subtype".  The value of the field "Type/Subtype" in the 
> 802.11 Data header is 0x0020.  The value of the field "Type/Subtype" 
> in the 802.11 QoS header is 0x0028.
> 
> The mapping between qos-related fields in the IPv6 header (e.g. 
> "Traffic Class", "Flow label") and fields in the "802.11 QoS Data 
> Header" (e.g.  "QoS Control") are not specified in this document. 
> Guidance for a potential mapping is provided in 
> [I-D.ietf-tsvwg-ieee-802-11 
> ],
> although it is not specific to OCB mode.
> 
> 
> 
> [Sri] The applicability of the QoS mapping draft to 802.11-OCB needs
>  further investigation, IMO.
> 
> 
> 
> 
> 5.3 
> .
>
> 
Link-Local Addresses
> 
> 
> 
> The link-local address of an 802.11-OCB interface is formed in the 
> same manner as on an Ethernet interface.  This manner is described
> in section 5 of [RFC2464]
> .
> 
> 
> 
> [Sri] Does this go against the 8064 recommendation on Interface 
> identifier generation?
> 
> May be RFC7217 for interface identifier generation in conjunction
> with the link-local address generation per RFC2464
> 
> 
> 
> 
> 
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> 
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> 
> 
> 5.4 
> .
>
> 
Address Mapping
> 
> 
> 
> For unicast as for multicast, there is no change from the unicast
> and multicast address mapping format of Ethernet interfaces, as
> defined by sections6 
> 
> and7 
> 
> of [RFC2464 ].
> 
> 
> 
> [Sri] RFC6085 specified mapping is also relevant; If the
> communication peers are aware that there is only one peer, it should
> apply 6085 specified mapping. That mode is relevant for 802.11-OCB
> types links as well.
> 
> 
> 
> 5.4.1 
> .
>
> 
Address Mapping -- Unicast
> 
> 
> 
> The procedure for mapping IPv6 unicast addresses into Ethernet link- 
> layer addresses is described in [RFC4861
> ].  The Source/Target Link- 
> layer Address option has the following form when the link-layer is 
> Ethernet.
> 
> [Sri] I thought, mapping of IPv6 unicast addresses to Ethernet 
> link-layer addresses is specified in section 6, of RFC2464 and not in
>  RFC4861.
> 
> 
> 
> 
> 0                   1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |     Type      |    Length     | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |                               | 
> +-          Ethernet           -+ |                               | 
> +-           Address           -+ |                               | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> 
> Option fields:
> 
> Type 1 for Source Link-layer address. 2 for Target Link-layer
> address.
> 
> Length 1 (in units of 8 octets).
> 
> Ethernet Address The 48 bit Ethernet IEEE 802 address, in canonical
> bit order.
> 
> 
> 5.4.2 
> .
>
> 
Address Mapping -- Multicast
> 
> 
> 
> IPv6 protocols often make use of IPv6 multicast addresses in the 
> destination field of IPv6 headers.  For example, an ICMPv6 link- 
> scoped Neighbor Advertisement is sent to the IPv6 address ff02::1 
> denoted "all-nodes" address.  When transmitting these packets on 
> 802.11-OCB links it is necessary to map the IPv6 address to a MAC 
> address.
> 
> 
> 
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> 
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> 
> 
> The same mapping requirement applies to the link-scoped multicast 
> addresses of other IPv6 protocols as well.  In DHCPv6, the 
> "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF the 
> "All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped 
> on a multicast MAC address.
> 
> An IPv6 packet with a multicast destination address DST, consisting 
> of the sixteen octets DST[1] through DST[16], is transmitted to the 
> IEEE 802.11-OCB MAC multicast address whose first two octets are the 
> value 0x3333 and whose last four octets are the last four octets of 
> DST.
> 
> [Sri] Please add a reference to Section 7, RFC4861 and also RFC6085.
> In general, for both unicast and multicast, you may want to clearly
> say that this is per the existing specs and duplicated here for
> convenience.
> 
> 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1| 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |   DST[13]     |   DST[14]     | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |   DST[15]     |   DST[16]     | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> 
> A Group ID TBD of length 112bits may be requested from IANA; this 
> Group ID signifies "All 80211OCB Interfaces Address".  Only the
> least 32 significant bits of this "All 80211OCB Interfaces Address"
> will be mapped to and from a MAC multicast address.
> 
> Transmitting IPv6 packets to multicast destinations over 802.11
> links proved to have some performance issues 
> [I-D.perkins-intarea-multicast-ieee802 
> ].
> These issues may be exacerbated in OCB mode.  Solutions for these
> problems should consider the OCB mode of operation.
> 
> 
> 5.5 
> .
>
> 
Stateless Autoconfiguration
> 
> 
> 
> The Interface Identifier for an 802.11-OCB interface is formed using 
> the same rules as the Interface Identifier for an Ethernet
> interface; this is described insection 4 of [RFC2464]
> .  No changes are
> needed, but some care must be taken when considering the use of the
> SLAAC procedure.
> 
> 
> 
> [Sri] Per my earlier comment, please refer to the current
> recommendation on interface-identifier generation and its use in
> link-local, global or other addresses.
> 
> The bits in the the interface identifier have no generic meaning and
> the identifier should be treated as an opaque value. The bits
> 'Universal' and 'Group' in the identifier of an 802.11-OCB interface
> are significant, as this is an IEEE link-layer address. The details
> of this significance are described in [I-D.ietf-6man-ug 
> ].
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> 
> 
> As with all Ethernet and 802.11 interface identifiers ([RFC7721
> ]), the identifier of an
> 802.11-OCB interface may involve privacy risks. A vehicle embarking
> an On-Board Unit whose egress interface is 802.11-OCB may expose
> itself to eavesdropping and subsequent correlation of data; this may
> reveal data considered private by the vehicle owner; there is a risk
> of being tracked; see the privacy considerations described inAppendix
> C 
> .
>
> 
> 
> [Sri] I think there are other security issues here; the absence of 
> link-layer security opens up Mac-spoofing and IP address hijacking.
> That should be mentioned.
> 
> 
> 
> If stable Interface Identifiers are needed in order to form IPv6 
> addresses on 802.11-OCB links, it is recommended to follow the 
> recommendation in [I-D.ietf-6man-default-iids 
> ].
>
> 
> 
> 5.6 
> .
>
> 
Subnet Structure
> 
> 
> 
> The 802.11 networks in OCB mode may be considered as 'ad-hoc' 
> networks.  The addressing model for such networks is described in 
> [RFC5889 ].
> 
> 
> [Sri] Per my earlier comment, there is no system level view of the 
> network where 802.11-OCB links are used. So, in the absence of such 
> discussion So, I am not sure what part of RFC5889 is applicable here.
>  For example, link-local addresses may just work fine.
> 
> 
> 
> 6 
> .
>
> 
Example IPv6 Packet captured over a IEEE 802.11-OCB link
> 
> 
> 
> We remind that a main goal of this document is to make the case that 
> IPv6 works fine over 802.11-OCB networks.  Consequently, this
> section is an illustration of this concept and thus can help the
> implementer when it comes to running IPv6 over IEEE 802.11-OCB.  By
> way of example we show that there is no modification in the headers
> when transmitted over 802.11-OCB networks - they are transmitted like
> any other 802.11 and Ethernet packets.
> 
> We describe an experiment of capturing an IPv6 packet on an 
> 802.11-OCB link.  In this experiment, the packet is an IPv6 Router 
> Advertisement.  This packet is emitted by a Router on its 802.11-OCB 
> interface.  The packet is captured on the Host, using a network 
> protocol analyzer (e.g.  Wireshark); the capture is performed in two 
> different modes: direct mode and 'monitor' mode.  The topology used 
> during the capture is depicted below.
> 
> 
> +--------+                                +-------+ |        |
> 802.11-OCB Link         |       | ---| Router
> |--------------------------------| Host  | |        |
> |       | +--------+                                +-------+
> 
> 
> During several capture operations running from a few moments to 
> several hours, no message relevant to the BSSID contexts were 
> captured (no Association Request/Response, Authentication Req/Resp,
> 
> 
> 
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> 
> 
> Beacon).  This shows that the operation of 802.11-OCB is outside the 
> context of a BSSID.
> 
> Overall, the captured message is identical with a capture of an IPv6 
> packet emitted on a 802.11b interface.  The contents are precisely 
> similar.
> 
> 
> [Sri] I suggest moving this discussion under the section
> “Implementation Status”, which will eventually be removed from the
> RFC. There is nothing new here. This are details on experimentation.
> But, if you think there is some useful information such as discussion
> on Capture mode ..etc, you may want to move this entire section to
> Appendix. Implementors may use these tools for verification.
> 
> 
> 
> 
> 6.1 
> .
>
> 
Capture in Monitor Mode
> 
> 
> 
> The IPv6 RA packet captured in monitor mode is illustrated below. The
> radio tap header provides more flexibility for reporting the 
> characteristics of frames.  The Radiotap Header is prepended by this 
> particular stack and operating system on the Host machine to the RA 
> packet received from the network (the Radiotap Header is not present 
> on the air).  The implementation-dependent Radiotap Header is useful 
> for piggybacking PHY information from the chip's registers as data
> in a packet understandable by userland applications using Socket 
> interfaces (the PHY interface can be, for example: power levels,
> data rate, ratio of signal to noise).
> 
> The packet present on the air is formed by IEEE 802.11 Data Header, 
> Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.
> 
> 
> 
> Radiotap Header v0 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
> |Header Revision|  Header Pad   |    Header length              | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Present flags                         | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Data Rate     |             Pad                               | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> IEEE 802.11 Data Header 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Type/Subtype and Frame Ctrl  |          Duration             | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Receiver Address... 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ...
> Receiver Address           |      Transmitter Address... 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ...
> Transmitter Address                                        | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> BSS Id... 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ...
> BSS Id                     |  Frag Number and Seq Number   | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 17]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> Logical-Link Control Header 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> DSAP   |I|     SSAP    |C| Control field | Org. code... 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ...
> Organizational Code        |             Type              | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> IPv6 Base Header 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
> |Version| Traffic Class |           Flow Label                  | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Payload Length        |  Next Header  |   Hop Limit   | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> | +                                                               + |
> | +                         Source Address                        + |
> | +                                                               + |
> | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> | +                                                               + |
> | +                      Destination Address                      + |
> | +                                                               + |
> | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> Router Advertisement 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Type      |     Code      |          Checksum             | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Cur Hop Limit |M|O|  Reserved |       Router Lifetime         | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Reachable Time                        | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Retrans Timer                        | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Options ... +-+-+-+-+-+-+-+-+-+-+-+-
> 
> 
> The value of the Data Rate field in the Radiotap header is set to 6 
> Mb/s.  This indicates the rate at which this RA was received.
> 
> 
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 18]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> The value of the Transmitter address in the IEEE 802.11 Data Header 
> is set to a 48bit value.  The value of the destination address is 
> 33:33:00:00:00:1 (all-nodes multicast address).  The value of the
> BSS Id field is ff:ff:ff:ff:ff:ff, which is recognized by the
> network protocol analyzer as being "broadcast".  The Fragment number
> and sequence number fields are together set to 0x90C6.
> 
> The value of the Organization Code field in the Logical-Link Control 
> Header is set to 0x0, recognized as "Encapsulated Ethernet".  The 
> value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 
> #86DD), recognized as "IPv6".
> 
> A Router Advertisement is periodically sent by the router to 
> multicast group address ff02::1.  It is an icmp packet type 134.
> The IPv6 Neighbor Discovery's Router Advertisement message contains
> an 8-bit field reserved for single-bit flags, as described in
> [RFC4861 ].
> 
> The IPv6 header contains the link local address of the router 
> (source) configured via EUI-64 algorithm, and destination address
> set to ff02::1.  Recent versions of network protocol analyzers (e.g. 
> Wireshark) provide additional informations for an IP address, if a 
> geolocalization database is present.  In this example, the 
> geolocalization database is absent, and the "GeoIP" information is 
> set to unknown for both source and destination addresses (although 
> the IPv6 source and destination addresses are set to useful values). 
> This "GeoIP" can be a useful information to look up the city, 
> country, AS number, and other information for an IP address.
> 
> 
> [Sri] Not sure, why all of this text should be in the specification.
> 
> 
> The Ethernet Type field in the logical-link control header is set to 
> 0x86dd which indicates that the frame transports an IPv6 packet.  In 
> the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 
> which is he corresponding multicast MAC address.  The BSS id is a 
> broadcast address of ff:ff:ff:ff:ff:ff.  Due to the short link 
> duration between vehicles and the roadside infrastructure, there is 
> no need in IEEE 802.11-OCB to wait for the completion of association 
> and authentication procedures before exchanging data.  IEEE 
> 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 
> and may start communicating as soon as they arrive on the 
> communication channel.
> 
> 
> 6.2 
> .
>
> 
Capture in Normal Mode
> 
> 
> 
> The same IPv6 Router Advertisement packet described above (monitor 
> mode) is captured on the Host, in the Normal mode, and depicted 
> below.
> 
> 
> 
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 19]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> Ethernet II Header 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Destination... 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
> ...Destination                 |           Source... 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
> ...Source                                                      | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Type                 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> IPv6 Base Header 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
> |Version| Traffic Class |           Flow Label                  | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Payload Length        |  Next Header  |   Hop Limit   | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> | +                                                               + |
> | +                         Source Address                        + |
> | +                                                               + |
> | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> | +                                                               + |
> | +                      Destination Address                      + |
> | +                                                               + |
> | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> Router Advertisement 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Type      |     Code      |          Checksum             | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Cur Hop Limit |M|O|  Reserved |       Router Lifetime         | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Reachable Time                        | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Retrans Timer                        | 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> Options ... +-+-+-+-+-+-+-+-+-+-+-+-
> 
> 
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 20]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> One notices that the Radiotap Header is not prepended, and that the 
> IEEE 802.11 Data Header and the Logical-Link Control Headers are not 
> present.  On another hand, a new header named Ethernet II Header is 
> present.
> 
> The Destination and Source addresses in the Ethernet II header 
> contain the same values as the fields Receiver Address and 
> Transmitter Address present in the IEEE 802.11 Data Header in the 
> "monitor" mode capture.
> 
> The value of the Type field in the Ethernet II header is 0x86DD 
> (recognized as "IPv6"); this value is the same value as the value of 
> the field Type in the Logical-Link Control Header in the "monitor" 
> mode capture.
> 
> The knowledgeable experimenter will no doubt notice the similarity
> of this Ethernet II Header with a capture in normal mode on a pure 
> Ethernet cable interface.
> 
> It may be interpreted that an Adaptation layer is inserted in a pure 
> IEEE 802.11 MAC packets in the air, before delivering to the 
> applications.  In detail, this adaptation layer may consist in 
> elimination of the Radiotap, 802.11 and LLC headers and insertion of 
> the Ethernet II header.  In this way, it can be stated that IPv6
> runs naturally straight over LLC over the 802.11-OCB MAC layer, as
> shown by the use of the Type 0x86DD, and assuming an adaptation
> layer (adapting 802.11 LLC/MAC to Ethernet II header).
> 
> 
> 7 
> .
>
> 
Security Considerations
> 
> 
> 
> Any security mechanism at the IP layer or above that may be carried 
> out for the general case of IPv6 may also be carried out for IPv6 
> operating over 802.11-OCB.
> 
> 
> 802.11-OCB does not provide any cryptographic protection, because it 
> operates outside the context of a BSS (no Association Request/ 
> Response, no Challenge messages).  Any attacker can therefore just 
> sit in the near range of vehicles, sniff the network (just set the 
> interface card's frequency to the proper range) and perform attacks 
> without needing to physically break any wall.  Such a link is way 
> less protected than commonly used links (wired link or protected 
> 802.11).
> 
> [Sri] Per my earlier comment, there is more than one attack vector
> possible
> 
> 1.) Absence of link-layer security and the potential for mac address
>  spoofing
> 
> 2.) IP address / Session hijacking
> 
> 3.) Data privacy per your text
> 
> 
> 
> At the IP layer, IPsec can be used to protect unicast
> communications, and SeND can be used for multicast communications.
> 
> 
> [Sri] IPSec can be used for protecting both multicast or unicast 
> communication; RFC-5374 with GDOI.
> 
> 
> 
> 
> If no protection is used by the IP layer, upper layers should be
> protected. Otherwise, the end-user or system should be warned about
> the risks they run.
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 21]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> As with all Ethernet and 802.11 interface identifiers, there may 
> exist privacy risks in the use of 802.11-OCB interface identifiers. 
> Moreover, in outdoors vehicular settings, the privacy risks are more 
> important than in indoors settings.  New risks are induced by the 
> possibility of attacker sniffers deployed along routes which listen 
> for IP packets of vehicles passing by.  For this reason, in the 
> 802.11-OCB deployments, there is a strong necessity to use
> protection tools such as dynamically changing MAC addresses.  This
> may help mitigate privacy risks to a certain level.  On another hand,
> it may have an impact in the way typical IPv6 address
> auto-configuration is performed for vehicles (SLAAC would rely on MAC
> addresses amd would hence dynamically change the affected IP
> address), in the way the IPv6 Privacy addresses were used, and other
> effects.
> 
> 
> 8 
> .
>
> 
IANA Considerations
> 
> 
> 
> 9 
> .
>
> 
Contributors
> 
> 
> 
> Romain Kuntz contributed extensively about IPv6 handovers between 
> links running outside the context of a BSS (802.11-OCB links).
> 
> Tim Leinmueller contributed the idea of the use of IPv6 over 
> 802.11-OCB for distribution of certificates.
> 
> Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 
> Voronov provided significant feedback on the experience of using IP 
> messages over 802.11-OCB in initial trials.
> 
> Michelle Wetterwald contributed extensively the MTU discussion, 
> offered the ETSI ITS perspective, and reviewed other parts of the 
> document.
> 
> 
> 10 
> .
>
> 
Acknowledgements
> 
> 
> 
> The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 
> Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 
> Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 
> Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 
> Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 
> Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 
> Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and 
> William Whyte.  Their valuable comments clarified certain issues and 
> generally helped to improve the document.
> 
> Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 
> drivers for linux and described how.
> 
> 
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 22]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> For the multicast discussion, the authors would like to thank Owen 
> DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 
> participants to discussions in network working groups.
> 
> The authours would like to thank participants to the Birds-of- 
> a-Feather "Intelligent Transportation Systems" meetings held at IETF 
> in 2016.
> 
> 
> 11 
> .
>
> 
References
> 
> 
> 
> 11.1 
> .
>
> 
Normative References
> 
> 
> 
> [I-D.ietf-6man-default-iids] Gont, F., Cooper, A., Thaler, D., and S.
> LIU, "Recommendation on Stable IPv6 Interface Identifiers", 
> draft-ietf-6man-default-iids-16 
>   (work
> in progress), September 2016.
> 
> [I-D.ietf-6man-ug] Carpenter, B. and S. Jiang, "Significance of IPv6 
> Interface Identifiers",draft-ietf-6man-ug-06
>   (work in 
> progress), December 2013.
> 
> [I-D.ietf-tsvwg-ieee-802-11] Szigeti, T., Henry, J., and F. Baker,
> "Diffserv to IEEE 802.11 Mapping",draft-ietf-tsvwg-ieee-802-11-06 
>   (work
> in progress), August 2017.
> 
> [RFC1042]  Postel, J. and J. Reynolds, "Standard for the
> transmission of IP datagrams over IEEE 802 networks", STD 43,RFC 1042
> , DOI 10.17487/RFC1042, February
> 1988,  
> editor.org/info/rfc1042 >.
> 
> [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate 
> Requirement Levels",BCP 14 ,RFC
> 2119 , DOI 10.17487/RFC2119,
> March 1997,   editor.org/info/rfc2119
> >.
> 
> [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6 
> (IPv6) Specification",RFC 2460 ,
> DOI 10.17487/RFC2460, December 1998,
> .
> 
> [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet 
> Networks",RFC 2464 , DOI
> 10.17487/RFC2464, December 1998, 
> .
> 
> 
> 
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 23]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> [RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P. 
> Thubert, "Network Mobility (NEMO) Basic Support Protocol", RFC 3963
> , DOI 10.17487/RFC3963, January
> 2005, .
> 
> [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker, 
> "Randomness Requirements for Security",BCP 106
> ,RFC 4086
> , DOI 10.17487/RFC4086, June
> 2005,  
> editor.org/info/rfc4086 >.
> 
> [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the 
> Internet Protocol",RFC 4301 ,
> DOI 10.17487/RFC4301, December 2005,
> .
> 
> [RFC4429]  Moore, N., "Optimistic Duplicate Address Detection (DAD) 
> for IPv6",RFC 4429 , DOI
> 10.17487/RFC4429, April 2006, 
> .
> 
> [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 
> "Neighbor Discovery for IP version 6 (IPv6)",RFC 4861
> , DOI 10.17487/RFC4861,
> September 2007,   editor.org/info/rfc4861
> >.
> 
> [RFC5889]  Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 
> Model in Ad Hoc Networks",RFC 5889
> , DOI 10.17487/RFC5889, 
> September 2010, .
> 
> [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 
> Support in IPv6",RFC 6275 , DOI
> 10.17487/RFC6275, July 2011,
> .
> 
> [RFC6775]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 
> Bormann, "Neighbor Discovery Optimization for IPv6 over Low-Power
> Wireless Personal Area Networks (6LoWPANs)", RFC 6775
> , DOI 10.17487/RFC6775, November
> 2012, .
> 
> [RFC7721]  Cooper, A., Gont, F., and D. Thaler, "Security and
> Privacy Considerations for IPv6 Address Generation Mechanisms", RFC
> 7721 , DOI 10.17487/RFC7721,
> March 2016, .
> 
> 
> 11.2 
> .
>
> 
Informative References
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Petrescu, et al. Expires February 18, 2018 [Page 24]
> 
> ------------------------------------------------------------------------
>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> [fcc-cc]   "'Report and Order, Before the Federal Communications 
> Commission Washington, D.C. 20554', FCC 03-324, Released on February
> 10, 2004, document FCC-03-324A1.pdf, document freely available at
> URL http://www.its.dot.gov/exit/fcc_edocs.htm  downloaded on October
> 17th, 2013.".
> 
> [fcc-cc-172-184] "'Memorandum Opinion and Order, Before the Federal 
> Communications Commission Washington, D.C. 20554', FCC 06-10,
> Released on July 26, 2006, document FCC- 06-110A1.pdf, document
> freely available at URL 
> http://hraunfoss.fcc.gov/edocs_public/attachmatch/ 
>  
> FCC-06-110A1.pdf 
> 
> downloaded on June 5th, 2014.".
> 
> [I-D.jeong-ipwave-vehicular-networking-survey] Jeong, J., Cespedes,
> S., Benamar, N., Haerri, J., and M. Wetterwald, "Survey on IP-based
> Vehicular Networking for Intelligent Transportation
> Systems",draft-jeong-ipwave- 
> 
>
> 
vehicular-networking-survey-03
> 
> (work in progress), June 2017.
> 
> [I-D.perkins-intarea-multicast-ieee802] Perkins, C., Stanley, D.,
> Kumari, W., and J. Zuniga, "Multicast Considerations over IEEE 802
> Wireless Media", draft-perkins-intarea-multicast-ieee802-03 
> 
> (work in progress), July 2017.
> 
> [I-D.petrescu-its-scenarios-reqs] Petrescu, A., Janneteau, C., Boc,
> M., and W. Klaudel, "Scenarios and Requirements for IP in
> Intelligent Transportation Systems",draft-petrescu-its-scenarios- 
>  
> reqs-03
> 
> (work in progress), October 2013.
> 
> [ieee1609.2] "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless
> Access in Vehicular Environments (WAVE) -- Security Services for 
> Applications and Management Messages.  Example URL 
> http://ieeexplore.ieee.org/document/7426684/  accessed on August
> 17th, 2017.".
> 
> [ieee1609.3] "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless
> Access in Vehicular Environments (WAVE) -- Networking Services. 
> Example URLhttp://ieeexplore.ieee.org/document/7458115/ 
>  accessed
>   on August
> 17th, 2017.".
> 
> 
> 
> 
> 
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> 
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>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> [ieee1609.4] "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless
> Access in Vehicular Environments (WAVE) -- Multi-Channel Operation.
> Example URL http://ieeexplore.ieee.org/document/7435228/  accessed
> on August 17th, 2017.".
> 
> [ieee802.11-2012] "802.11-2012 - IEEE Standard for Information
> technology-- Telecommunications and information exchange between 
> systems Local and metropolitan area networks--Specific requirements
> Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer
> (PHY) Specifications.  Downloaded on October 17th, 2013, from IEEE
> Standards, document freely available at URL 
> http://standards.ieee.org/findstds/ 
>  
> standard/802.11-2012.html 
> 
> retrieved on October 17th, 2013.".
> 
> [ieee802.11p-2010] "IEEE Std 802.11p (TM)-2010, IEEE Standard for
> Information Technology - Telecommunications and information exchange 
> between systems - Local and metropolitan area networks - Specific
> requirements, Part 11: Wireless LAN Medium Access Control (MAC) and
> Physical Layer (PHY) Specifications, Amendment 6: Wireless Access in
> Vehicular Environments; document freely available at URL 
> http://standards.ieee.org/getieee802/ 
>  
> download/802.11p-2010.pdf 
> 
> retrieved on September 20th, 2013.".
> 
> 
> Appendix A 
> .
>
> 
ChangeLog
> 
> 
> 
> The changes are listed in reverse chronological order, most recent 
> changes appearing at the top of the list.
> 
> Fromdraft-ietf-ipwave-ipv6-over-80211ocb-03 
> 
> todraft-ietf-ipwave- 
> 
>
> 
ipv6-over-80211ocb-04
> 
>
>  o  Removed a few informative references pointing to Dx draft IEEE 
> 1609 documents.
> 
> o  Removed outdated informative references to ETSI documents.
> 
> o  Added citations to IEEE 1609.2, .3 and .4-2016.
> 
> o  Minor textual issues.
> 
> 
> 
> 
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> 
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>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> Fromdraft-ietf-ipwave-ipv6-over-80211ocb-02 
> 
> todraft-ietf-ipwave- 
> 
>
> 
ipv6-over-80211ocb-03
> 
>
>  o  Keep the previous text on multiple addresses, so remove talk
> about MIP6, NEMOv6 and MCoA.
> 
> o  Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon.
> 
> o  Clarified the figure showing Infrastructure mode and OCB mode
> side by side.
> 
> o  Added a reference to the IP Security Architecture RFC.
> 
> o  Detailed the IPv6-per-channel prohibition paragraph which
> reflects the discussion at the last IETF IPWAVE WG meeting.
> 
> o  Added section "Address Mapping -- Unicast".
> 
> o  Added the ".11 Trailer" to pictures of 802.11 frames.
> 
> o  Added text about SNAP carrying the Ethertype.
> 
> o  New RSU definition allowing for it be both a Router and not 
> necessarily a Router some times.
> 
> o  Minor textual issues.
> 
> Fromdraft-ietf-ipwave-ipv6-over-80211ocb-01 
> 
> todraft-ietf-ipwave- 
> 
>
> 
ipv6-over-80211ocb-02
> 
>
>  o  Replaced almost all occurences of 802.11p with 802.11-OCB,
> leaving only when explanation of evolution was necessary.
> 
> o  Shortened by removing parameter details from a paragraph in the 
> Introduction.
> 
> o  Moved a reference from Normative to Informative.
> 
> o  Added text in intro clarifying there is no handover spec at IEEE, 
> and that 1609.2 does provide security services.
> 
> o  Named the contents the fields of the EthernetII header (including 
> the Ethertype bitstring).
> 
> o  Improved relationship between two paragraphs describing the 
> increase of the Sequence Number in 802.11 header upon IP 
> fragmentation.
> 
> 
> 
> 
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> 
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>
>  
> 
>
> 
Internet-Draft IPv6-over-80211ocb August 2017
> 
> 
> o  Added brief clarification of "tracking".
> 
> Fromdraft-ietf-ipwave-ipv6-over-80211ocb-00 
> 
> todraft-ietf-ipwave- 
> 
>
> 
ipv6-over-80211ocb-01
> 
>
>  o  Introduced message exchange diagram illustrating differences 
> between 802.11 and 802.11 in OCB mode.
> 
> o  Introduced an appendix listing for information the set of 802.11 
> messages that may be transmitted in OCB mode.
> 
> o  Removed appendix sections "Privacy Requirements", "Authentication 
> Requirements" and "Security Certificate Generation".
> 
> o  Removed appendix section "Non IP Communications".
> 
> o  Introductory phrase in the Security Considerations section.
> 
> o  Improved the definition of "OCB".
> 
> o  Introduced theoretical stacked layers about IPv6 and IEEE layers 
> including EPD.
> 
> o  Removed the appendix describing the details of prohibiting IPv6
> on certain channels relevant to 802.11-OCB.
> 
> o  Added a brief reference in the privacy text about a precise
> clause in IEEE 1609.3 and .4.
> 
> o  Clarified the definition of a Road Side Unit.
> 
> o  Removed the discussion about security of WSA (because is non-IP).
> 
> o  Removed mentioning of the GeoNetworking discussion.
> 
> o  Moved references to scientific articles to a separate 'overview' 
> draft, and referred to it.
> 
> 
> Appendix B 
> .
>
> 
Changes Needed on a software driver 802.11a to become a
> 
> 
> 802.11-OCB driver
> 
> The 802.11p amendment modifies both the 802.11 stack's physical and 
> MAC layers but all the induced modifications can be quite easily 
> obtained by modifying an existing 802.11a ad-hoc stack.
> 
> Conditions for a 802.11a hardware to be 802.11-OCB compliant:
> 
> 
> 
> 
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> 
> o  The chip must support the frequency bands on which the regulator 
> recommends the use of ITS communications, for example using IEEE 
> 802.11-OCB layer, in France: 5875MHz to 5925MHz.
> 
> o  The chip must support the half-rate mode (the internal clock 
> should be able to be divided by two).
> 
> o  The chip transmit spectrum mask must be compliant to the
> "Transmit spectrum mask" from the IEEE 802.11p amendment (but
> experimental environments tolerate otherwise).
> 
> o  The chip should be able to transmit up to 44.8 dBm when used by 
> the US government in the United States, and up to 33 dBm in Europe;
> other regional conditions apply.
> 
> Changes needed on the network stack in OCB mode:
> 
> o  Physical layer:
> 
> *  The chip must use the Orthogonal Frequency Multiple Access (OFDM)
> encoding mode.
> 
> *  The chip must be set in half-mode rate mode (the internal clock 
> frequency is divided by two).
> 
> *  The chip must use dedicated channels and should allow the use of
> higher emission powers.  This may require modifications to the
> regulatory domains rules, if used by the kernel to enforce local
> specific restrictions.  Such modifications must respect the
> location-specific laws.
> 
> MAC layer:
> 
> *  All management frames (beacons, join, leave, and others) emission
> and reception must be disabled except for frames of subtype Action
> and Timing Advertisement (defined below).
> 
> *  No encryption key or method must be used.
> 
> *  Packet emission and reception must be performed as in ad-hoc mode,
> using the wildcard BSSID (ff:ff:ff:ff:ff:ff).
> 
> *  The functions related to joining a BSS (Association Request/ 
> Response) and for authentication (Authentication Request/Reply, 
> Challenge) are not called.
> 
> *  The beacon interval is always set to 0 (zero).
> 
> 
> 
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> 
> *  Timing Advertisement frames, defined in the amendment, should be
> supported.  The upper layer should be able to trigger such frames
> emission and to retrieve information contained in received Timing
> Advertisements.
> 
> 
> Appendix C 
> .
>
> 
Design Considerations
> 
> 
> 
> The networks defined by 802.11-OCB are in many ways similar to other 
> networks of the 802.11 family.  In theory, the encapsulation of IPv6 
> over 802.11-OCB could be very similar to the operation of IPv6 over 
> other networks of the 802.11 family.  However, the high mobility, 
> strong link asymetry and very short connection makes the 802.11-OCB 
> link significantly different from other 802.11 networks.  Also, the 
> automotive applications have specific requirements for reliability, 
> security and privacy, which further add to the particularity of the 
> 802.11-OCB link.
> 
> 
> C.1 
> .
>
> 
Vehicle ID
> 
> 
> 
> Automotive networks require the unique representation of each of 
> their node.  Accordingly, a vehicle must be identified by at least 
> one unique identifier.  The current specification at ETSI and at
> IEEE 1609 identifies a vehicle by its MAC address uniquely obtained
> from the 802.11-OCB NIC.
> 
> A MAC address uniquely obtained from a IEEE 802.11-OCB NIC 
> implicitely generates multiple vehicle IDs in case of multiple 
> 802.11-OCB NICs.  A mechanims to uniquely identify a vehicle 
> irrespectively to the different NICs and/or technologies is
> required.
> 
> 
> C.2 
> .
>
> 
Reliability Requirements
> 
> 
> 
> The dynamically changing topology, short connectivity, mobile 
> transmitter and receivers, different antenna heights, and many-to- 
> many communication types, make IEEE 802.11-OCB links significantly 
> different from other IEEE 802.11 links.  Any IPv6 mechanism
> operating on IEEE 802.11-OCB link MUST support strong link asymetry,
> spatio- temporal link quality, fast address resolution and
> transmission.
> 
> IEEE 802.11-OCB strongly differs from other 802.11 systems to
> operate outside of the context of a Basic Service Set.  This means
> in practice that IEEE 802.11-OCB does not rely on a Base Station for
> all Basic Service Set management.  In particular, IEEE 802.11-OCB
> SHALL NOT use beacons.  Any IPv6 mechanism requiring L2 services from
> IEEE 802.11 beacons MUST support an alternative service.
> 
> 
> 
> 
> 
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> 
> Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST 
> implement a mechanism for transmitter and receiver to converge to a 
> common channel.
> 
> Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST 
> implement an distributed mechanism to authenticate transmitters and 
> receivers without the support of a DHCP server.
> 
> Time synchronization not being available, IPv6 over IEEE 802.11-OCB 
> MUST implement a higher layer mechanism for time synchronization 
> between transmitters and receivers without the support of a NTP 
> server.
> 
> The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB 
> MUST disable management mechanisms requesting acknowledgements or 
> replies.
> 
> The IEEE 802.11-OCB link having a short duration time, IPv6 over
> IEEE 802.11-OCB MUST implement fast IPv6 mobility management
> mechanisms.
> 
> 
> C.3 
> .
>
> 
Multiple interfaces
> 
> 
> 
> There are considerations for 2 or more IEEE 802.11-OCB interface 
> cards per vehicle.  For each vehicle taking part in road traffic,
> one IEEE 802.11-OCB interface card could be fully allocated for Non
> IP safety-critical communication.  Any other IEEE 802.11-OCB may be
> used for other type of traffic.
> 
> The mode of operation of these other wireless interfaces is not 
> clearly defined yet.  One possibility is to consider each card as an 
> independent network interface, with a specific MAC Address and a set 
> of IPv6 addresses.  Another possibility is to consider the set of 
> these wireless interfaces as a single network interface (not 
> including the IEEE 802.11-OCB interface used by Non IP safety 
> critical communications).  This will require specific logic to 
> ensure, for example, that packets meant for a vehicle in front are 
> actually sent by the radio in the front, or that multiple copies of 
> the same packet received by multiple interfaces are treated as a 
> single packet.  Treating each wireless interface as a separate 
> network interface pushes such issues to the application layer.
> 
> The privacy requirements of [] imply that if these multiple 
> interfaces are represented by many network interface, a single 
> renumbering event SHALL cause renumbering of all these interfaces. If
> one MAC changed and another stayed constant, external observers would
> be able to correlate old and new values, and the privacy benefits of
> randomization would be lost.
> 
> 
> 
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> 
> 
> The privacy requirements of Non IP safety-critical communications 
> imply that if a change of pseudonyme occurs, renumbering of all
> other interfaces SHALL also occur.
> 
> 
> C.4 
> .
>
> 
MAC Address Generation
> 
> 
> 
> When designing the IPv6 over 802.11-OCB address mapping, we will 
> assume that the MAC Addresses will change during well defined 
> "renumbering events".  The 48 bits randomized MAC addresses will
> have the following characteristics:
> 
> o  Bit "Local/Global" set to "locally admninistered".
> 
> o  Bit "Unicast/Multicast" set to "Unicast".
> 
> o  46 remaining bits set to a random value, using a random number 
> generator that meets the requirements of [RFC4086
> ].
> 
> The way to meet the randomization requirements is to retain 46 bits 
> from the output of a strong hash function, such as SHA256, taking as 
> input a 256 bit local secret, the "nominal" MAC Address of the 
> interface, and a representation of the date and time of the 
> renumbering event.
> 
> 
> Appendix D 
> .
>
> 
IEEE 802.11 Messages Transmitted in OCB mode
> 
> 
> 
> For information, at the time of writing, this is the list of IEEE 
> 802.11 messages that may be transmitted in OCB mode, i.e. when 
> dot11OCBActivated is true in a STA:
> 
> o  The STA may send management frames of subtype Action and, if the 
> STA maintains a TSF Timer, subtype Timing Advertisement;
> 
> o  The STA may send control frames, except those of subtype PS-Poll, 
> CF-End, and CF-End plus CFAck;
> 
> o  The STA may send data frames of subtype Data, Null, QoS Data, and 
> QoS Null.
> 
> Authors' Addresses
> 
> 
> 
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