From terry@terrym.net Wed Feb 3 16:03:30 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id F05593A68E1 for ; Wed, 3 Feb 2010 16:03:29 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -2.599 X-Spam-Level: X-Spam-Status: No, score=-2.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fQwg5K4yJ9o7 for ; Wed, 3 Feb 2010 16:03:29 -0800 (PST) Received: from ey-out-2122.google.com (ey-out-2122.google.com [74.125.78.26]) by core3.amsl.com (Postfix) with ESMTP id D029D3A689D for ; Wed, 3 Feb 2010 16:03:28 -0800 (PST) Received: by ey-out-2122.google.com with SMTP id 22so498040eye.51 for ; Wed, 03 Feb 2010 16:04:09 -0800 (PST) Received: by 10.213.109.140 with SMTP id j12mr201369ebp.84.1265241849264; Wed, 03 Feb 2010 16:04:09 -0800 (PST) Received: from ?192.168.1.101? (c122-104-151-4.fitzg3.qld.optusnet.com.au [122.104.151.4]) by mx.google.com with ESMTPS id 14sm1166864ewy.11.2010.02.03.16.04.06 (version=TLSv1/SSLv3 cipher=RC4-MD5); Wed, 03 Feb 2010 16:04:08 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Apple Message framework v1077) From: Terry manderson In-Reply-To: <4B4FA7AA.1090204@joelhalpern.com> Date: Thu, 4 Feb 2010 10:04:01 +1000 Content-Transfer-Encoding: quoted-printable Message-Id: <16E4E038-9870-4CAF-AEA6-F51A9E45D9DB@terrym.net> References: <4B4FA7AA.1090204@joelhalpern.com> To: lisp@ietf.org X-Mailer: Apple Mail (2.1077) Subject: Re: [lisp] WG Secretary X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Feb 2010 00:03:30 -0000 Folks, Just to remind you, we are still seeking someone to take on the LISP = secretary role. The LISP working-group charter has set the bar quite = high and if we are to have documents published this year there will be a = lot of exciting and vibrant action. What better way to be involved! Taking on the WG secretary role is an ideal way for you to become = involved in the chairing aspects of IETF work groups It also signals to = all your peers the commitment you make to the standards development = process, to such an extent that it may just be the perfect lead-in role = to being a work group chair yourself!=20 If you are interested please email Joel or myself ASAP and we will talk = you through it. Cheers Terry On 15/01/2010, at 9:24 AM, Joel M. Halpern wrote: > At IETF meetings, there is often the interesting spot at the beginning = of meetings while the chairs look for a minute taker. > There are also times between meetings when it is helpful to have = someone who has committed to take notes of things. > The practice has started developing to appoint working group = secretaries. This person is acknowledged in the Charter for the Working = Group. This person commits to coming to the meeting and taking notes, = and to helping the chairs out somewhat in between. >=20 > It is generally good if this is NOT someone who is presenting a lot, = since it is rather difficult to take notes and present at the same time. >=20 > Terry and I are looking for a volunteer to step forward and assit the = group in the role of WG secretary. > Please! >=20 > Yours, > Joel (and Terry) > _______________________________________________ > lisp mailing list > lisp@ietf.org > https://www.ietf.org/mailman/listinfo/lisp From terry.manderson@icann.org Wed Feb 3 16:58:58 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 4BADF3A690C for ; Wed, 3 Feb 2010 16:58:58 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -6.599 X-Spam-Level: X-Spam-Status: No, score=-6.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ieba2qQ10Aqr for ; Wed, 3 Feb 2010 16:58:57 -0800 (PST) Received: from EXPFE100-2.exc.icann.org (expfe100-2.exc.icann.org [64.78.22.237]) by core3.amsl.com (Postfix) with ESMTP id 7FE753A6856 for ; Wed, 3 Feb 2010 16:58:57 -0800 (PST) Received: from EXVPMBX100-1.exc.icann.org ([64.78.22.232]) by EXPFE100-2.exc.icann.org ([64.78.22.237]) with mapi; Wed, 3 Feb 2010 16:59:41 -0800 From: Terry Manderson To: "lisp@ietf.org" Date: Wed, 3 Feb 2010 16:59:39 -0800 Thread-Topic: Timelines for IETF77 and new versions Thread-Index: AcqlNVO5N2r50JmDCEWhDRz1nRxbtg== Message-ID: Accept-Language: en, en-US Content-Language: en X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en, en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: [lisp] Timelines for IETF77 and new versions X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Feb 2010 00:58:58 -0000 Folks, I'd just like to cover some administrative items. The timeline you need to be aware of is: * 2010-03-01 (Monday): Internet Draft Cut-off for initial document (-00) submission by 17:00 PST (01:00 Tuesday, March 2 UTC), upload using IETF ID Submission Tool. * 2010-03-08 (Monday): Internet Draft final submission cut-off by 17:00 PST (01:00 Tuesday, March 9 UTC), upload using IETF ID Submission Tool. * 2010-03-12 (Friday): Early Bird registration and payment cut-off at 17:00 PST (01:00 Saturday, March 13 UTC). * 2010-03-15 (Monday): Registration cancellation cut-off at 17:00 PDT (24:0= 0 UTC). * 2010-03-19 (Friday): Final Pre-Registration and Pre-Payment cut-off at 17:00 PDT (24:00 UTC). ** 2010-03-21 - 2010-03-26: 77th IETF Meeting in Anaheim, California, USA. Please note that we (Joel and I), as chairs, are not accepting any new item= s unless they are 100% in charter and will not detract from the work at hand. to remind you, that work is (from charter): Goals and Milestones: Mar 2010 - Submit base LISP specification to the IESG as Experimental Mar 2010 - Submit base ALT specification to the IESG as Experimental Mar 2010 - Submit the LISP Interworking specification to the IESG as Experimental Jun 2010 - Submit the LISP Map Server specification to the IESG as Experimental Jun 2010 - Submit Recommendations for Securing the LISP Mapping System to the IESG as Experimental Jul 2010 - Submit LISP for Multicast Environments to the IESG as Experimental Dec 2010 - Submit a preliminary analysis as Informational Dec 2010 - Re-charter or close. If you are considering presenting at IETF 77, it would be appreciated if yo= u could contact Joel and myself sooner rather than later! Lastly, I hope you have noticed that the following documents have new versions: draft-ietf-lisp draft-ietf-lisp-alt So this is a reminder for ALL to review the documents and email comments to the list. Cheers Terry & Joel. From amos@oasis-tech.net Sat Feb 6 11:04:16 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 7F03928C124 for ; Sat, 6 Feb 2010 11:04:16 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -0.74 X-Spam-Level: X-Spam-Status: No, score=-0.74 tagged_above=-999 required=5 tests=[BAYES_20=-0.74] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dUjsl23wpLn9 for ; Sat, 6 Feb 2010 11:04:15 -0800 (PST) Received: from mtaout20.012.net.il (mtaout20.012.net.il [80.179.55.166]) by core3.amsl.com (Postfix) with ESMTP id AB4433A692C for ; Sat, 6 Feb 2010 11:04:14 -0800 (PST) Received: from conversion-daemon.a-mtaout20.012.net.il by a-mtaout20.012.net.il (HyperSendmail v2007.08) id <0KXF00700OTT2H00@a-mtaout20.012.net.il> for lisp@ietf.org; Sat, 06 Feb 2010 21:04:09 +0200 (IST) Received: from [192.168.254.12] ([192.117.158.233]) by a-mtaout20.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0KXF00541OYSUK40@a-mtaout20.012.net.il> for lisp@ietf.org; Sat, 06 Feb 2010 21:04:06 +0200 (IST) Date: Sat, 06 Feb 2010 21:04:03 +0200 From: Amos Rosenboim X-012-Sender: slick@inter.net.il To: lisp@ietf.org Message-id: MIME-version: 1.0 (Apple Message framework v936) X-Mailer: Apple Mail (2.936) Content-type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-transfer-encoding: 7bit X-Mailman-Approved-At: Sun, 07 Feb 2010 08:02:44 -0800 Subject: [lisp] experimenting with lisp X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 06 Feb 2010 19:08:12 -0000 Hello, I read a little about lisp both in NANOG tutorial as well as some Cisco documentation. Are you looking to extend the lisp deployment and add testers and sites? If so I will be more than happy to participate. Regards Amos From dino@cisco.com Tue Feb 9 09:50:14 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 8B80728C24F for ; Tue, 9 Feb 2010 09:50:14 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -10.242 X-Spam-Level: X-Spam-Status: No, score=-10.242 tagged_above=-999 required=5 tests=[AWL=-0.357, BAYES_00=-2.599, HTML_COMMENT_SAVED_URL=0.114, HTML_MESSAGE=0.001, J_CHICKENPOX_43=0.6, RCVD_IN_DNSWL_HI=-8] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EW-O0M8tN96p for ; Tue, 9 Feb 2010 09:50:10 -0800 (PST) Received: from sj-iport-6.cisco.com (sj-iport-6.cisco.com [171.71.176.117]) by core3.amsl.com (Postfix) with ESMTP id AFB6928C24B for ; Tue, 9 Feb 2010 09:50:10 -0800 (PST) Authentication-Results: sj-iport-6.cisco.com; dkim=neutral (message not signed) header.i=none X-Files: draft-farinacci-lisp-lig-02.txt, rfcdiff-lisp-lig-01-to-02.html : 24591, 24724 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApoEAN8vcUurR7Hu/2dsb2JhbADCa4ohjXiCSQiCAwSORw X-IronPort-AV: E=Sophos;i="4.49,437,1262563200"; d="txt'?html'217?scan'217,208,217";a="480565519" Received: from sj-core-5.cisco.com ([171.71.177.238]) by sj-iport-6.cisco.com with ESMTP; 09 Feb 2010 17:51:16 +0000 Received: from xbh-sjc-211.amer.cisco.com (xbh-sjc-211.cisco.com [171.70.151.144]) by sj-core-5.cisco.com (8.13.8/8.14.3) with ESMTP id o19HpGL8026283 for ; Tue, 9 Feb 2010 17:51:16 GMT Received: from xfe-sjc-211.amer.cisco.com ([171.70.151.174]) by xbh-sjc-211.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.3959); Tue, 9 Feb 2010 09:51:16 -0800 Received: from [192.168.5.214] ([10.21.114.100]) by xfe-sjc-211.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.3959); Tue, 9 Feb 2010 09:51:15 -0800 Message-Id: <47E76F21-47C3-4373-998B-0D6F57F1A6E5@cisco.com> From: Dino Farinacci To: lisp@ietf.org Content-Type: multipart/mixed; boundary=Apple-Mail-2--332133380 Mime-Version: 1.0 (Apple Message framework v936) Date: Tue, 9 Feb 2010 09:51:15 -0800 X-Mailer: Apple Mail (2.936) X-OriginalArrivalTime: 09 Feb 2010 17:51:15.0846 (UTC) FILETIME=[79EE0260:01CAA9B0] Subject: [lisp] New lig draft -02 version update X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Feb 2010 17:50:14 -0000 --Apple-Mail-2--332133380 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Since the lig ID expired, we did a refresh update. ID and diff file enclosed. Thanks, Dino/Dave --Apple-Mail-2--332133380 Content-Disposition: attachment; filename=draft-farinacci-lisp-lig-02.txt Content-Type: text/plain; x-unix-mode=0644; name="draft-farinacci-lisp-lig-02.txt" Content-Transfer-Encoding: quoted-printable Network Working Group D. Farinacci Internet-Draft D. Meyer Intended status: Experimental cisco Systems Expires: August 13, 2010 February 9, 2010 LISP Internet Groper (LIG) draft-farinacci-lisp-lig-02.txt Abstract A simple tool called the LISP Internet Groper or 'lig' can be used to query the LISP mapping database. This draft describes how it works. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 13, 2010. Copyright Notice Copyright (c) 2010 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 Farinacci & Meyer Expires August 13, 2010 [Page 1] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 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 BSD License. Table of Contents 1. Requirements Notation . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 5 4. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . . 7 5. Implementation Details . . . . . . . . . . . . . . . . . . . . 9 5.1. LISP Router Implementation . . . . . . . . . . . . . . . . 9 5.2. Public Domain Host Implementation . . . . . . . . . . . . 10 6. Testing the ALT . . . . . . . . . . . . . . . . . . . . . . . 12 7. Future Enhancements . . . . . . . . . . . . . . . . . . . . . 13 8. Deployed Network Diagnostic Tools . . . . . . . . . . . . . . 14 9. Security Considerations . . . . . . . . . . . . . . . . . . . 15 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 10.2. Informative References . . . . . . . . . . . . . . . . . . 16 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Farinacci & Meyer Expires August 13, 2010 [Page 2] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 1. Requirements Notation 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 [RFC2119]. Farinacci & Meyer Expires August 13, 2010 [Page 3] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 2. Introduction LISP [LISP] specifies an architecture and mechanism for replacing the addresses currently used by IP with two separate name spaces: Endpoint IDS (EIDs), used within sites, and Routing Locators (RLOCs), used on the transit networks that make up the Internet infrastructure. To achieve this separation, the Locator/ID Separation Protocol (LISP) defines protocol mechanisms for mapping from EIDs to RLOCs. In addition, LISP assumes the existence of a database to store and propagate those mappings globally. Several such databases have been proposed, among them: LISP-CONS [CONS], LISP-NERD [NERD], and LISP+ALT [ALT], with LISP+ALT being the system that is currently being implemented and deployed on the pilot LISP network. In conjunction with the various mapping systems, there exists a network based API called LISP Map-Server [LISP-MS]. Using Map Resolvers and Map Servers allows LISP sites to query and register into the database in a uniform way independent of the mapping system used. Sending Map-Requests to Map Resolvers provides a secure mechanism mechanism to obtain a Map-Reply containing the authoritative EID-to-RLOC mapping for a destination LISP site. The 'lig' is a manual management tool to query the mapping database. It can be run by all devices which implement LISP, including ITRs, ETRs, PTR, Map-Resolvers, Map-Servers, and LISP-ALT routers, as well as by a host system at either a LISP-capable or non-LISP-capable site. Farinacci & Meyer Expires August 13, 2010 [Page 4] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 3. Definition of Terms Map-Server: a network infrastructure component which learns EID-to- RLOC mapping entries from an authoritative source (typically, an ETR, though static configuration or another out-of-band mechanism may be used). A Map-Server advertises these mappings in the distributed mapping database. Map-Resolver: a network infrastructure component which accepts LISP Encapsulated Map-Requests, typically from an ITR, quickly determines whether or not the destination IP address is part of the EID namespace; if it is not, a Negative Map-Reply is immediately returned. Otherwise, the Map-Resolver finds the appropriate EID-to-RLOC mapping by consulting the distributed mapping database system. Routing Locator (RLOC): the IPv4 or IPv6 address of an egress tunnel router (ETR). It is the output of a EID-to-RLOC mapping lookup. An EID maps to one or more RLOCs. Typically, RLOCs are numbered from topologically-aggregatable blocks that are assigned to a site at each point to which it attaches to the global Internet; where the topology is defined by the connectivity of provider networks, RLOCs can be thought of as PA addresses. Multiple RLOCs can be assigned to the same ETR device or to multiple ETR devices at a site. Endpoint ID (EID): a 32-bit (for IPv4) or 128-bit (for IPv6) value used in the source and destination address fields of the first (most inner) LISP header of a packet. The host obtains a destination EID the same way it obtains an destination address today, for example through a DNS lookup or SIP exchange. The source EID is obtained via existing mechanisms used to set a host's "local" IP address. An EID is allocated to a host from an EID-prefix block associated with the site where the host is located. An EID can be used by a host to refer to other hosts. EIDs MUST NOT be used as LISP RLOCs. Note that EID blocks may be assigned in a hierarchical manner, independent of the network topology, to facilitate scaling of the mapping database. In addition, an EID block assigned to a site may have site-local structure (subnetting) for routing within the site; this structure is not visible to the global routing system. EID-to-RLOC Cache: a short-lived, on-demand table in an ITR that stores, tracks, and is responsible for timing-out and otherwise validating EID-to-RLOC mappings. This cache is distinct from the full "database" of EID-to-RLOC mappings, it is dynamic, local to the ITR(s), and relatively small while the database is distributed, relatively static, and much more global in scope. Farinacci & Meyer Expires August 13, 2010 [Page 5] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 EID-to-RLOC Database: a global distributed database that contains all known EID-prefix to RLOC mappings. Each potential ETR typically contains a small piece of the database: the EID-to-RLOC mappings for the EID prefixes "behind" the router. These map to one of the router's own, globally-visible, IP addresses. Encapsulated Map-Request (EMR): an EMR is a Map-Request message which is encapsulated with another LISP header using UDP destination port number 4341. It is used so an ITR, PTR, or a system initiating a 'lig' command can get the Map-Request to a Map-Resolver by using locater addresses. When the Map-Request is decapsulated by the Map-Resolver it will be forwarded on the ALT network to the Map-Server that has injected the EID-prefix for a registered site. The Map-Server will then encapsulate the Map- Request in a LISP packet and send it to an an ETR at the site. The ETR will then return an authoritative reply to the system that initiated the request. Farinacci & Meyer Expires August 13, 2010 [Page 6] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 4. Basic Overview When the lig command is run, a Map-Request is sent for a destination EID. When a Map-Reply is returned, the contents are displayed to the user. The information displayed includes: o The EID-prefix for the site the queried destination EID matches. o The locator address of the Map Replier. o The locator-set for the mapping entry which includes the locator address, up/down status, priority, and weight of each locator. o An round-trip-time estimate for the Map-Request/Map-Reply exchange. A possible syntax for a lig command could be: lig [source ] [to ] Parameter description: : is either a Fully Qualified Domain Name or a destination EID for a remote LISP site. source : is an optional source EID to be inserted in the "Source EID" field of the Map-Request. to : is an optional Fully Qualified Domain Name or RLOC address for a Map-Resolver. The lig utility has two usage cases. The first being a way to query the mapping database for a particular EID. And the other to verify if a site has registered successfully with a Map-Server. The first usage has already been described. Verifying registration is called "ligging yourself". What occurs is in the lig initiator, a Map-Request is sent for one of the EIDs for the lig initiator's site. The Map-Request is then returned to one of the ETRs for the lig initiating site. In response to the Map-Request, a Map-Reply is sent back to the locator address of the lig initiator (note the Map-Reply could be sent by the lig initiator). That Map-Reply is processed and the mapping data for lig initiating site is displayed for the user. Refer to the syntax in section Section 5.1 for an implementation of "ligging yourself". However, for host-based implementations within a LISP site, "lig self" is less useful since the host may not have an RLOC to receive a Map-Reply with. But, lig can be used in a non-LISP Farinacci & Meyer Expires August 13, 2010 [Page 7] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 site as well as from infrastructure hosts to get mapping information. Farinacci & Meyer Expires August 13, 2010 [Page 8] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 5. Implementation Details 5.1. LISP Router Implementation The cisco LISP prototype implementation has support for lig for IPv4 and IPv6. The command line description is: lig [source ] [to ] [count <1-5>] This command initiates the LISP Internet Groper. It is similar to the DNS analogue 'dig' but works on the LISP mapping database. When this command is invoked, the local system will send a Map-Request to the configured Map-Resolver. When a Map-Reply is returned, its contents will be displayed to the user. By default, up to 3 Map- Requests are sent if no Map-Reply is returned but once a Map-Reply is returned no other Map-Requests are sent. The destination can take a DNS name, or an IPv4 or IPv6 EID address. The can be one of the EID addresses assigned to the site in the default VRF. When is specified, then the Map-Request is sent to the address. Otherwise, the Map-Request is sent to a configured Map-Resolver. When a Map-Resolver is not configured then the Map-Request is sent on the ALT network if the local router is attached to the ALT. When "count <1-5>" is specified, 1, 2, 3, 4, or 5 Map-Requests are sent. Some sample output: titanium-dino# lig titanium-dmm.lisp4.net Send map-request to 10.0.0.1 for 192.168.1.1 ... Received map-reply from 10.0.0.2 with rtt 0.081468 secs Map-cache entry for titanium-dmm.lisp4.net EID 192.168.1.1: 192.168.1.0/24, uptime: 13:59:59, expires: 23:59:58, via map-reply, auth Locator Uptime State Priority/Weight Packets In/Out 10.0.0.2 13:59:59 up 1/100 0/14 Using lig to "lig yourself" is accomplished with the following syntax: lig {self | self6} [source ] [to ] [count <1-5>] Use this command for a simple way to see if the site is registered with the mapping database system. The destination-EID address for the Map-Request will be the first configured EID-prefix for the site (with the host-bits set to 0). For example, if the site's EID-prefix Farinacci & Meyer Expires August 13, 2010 [Page 9] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 is 192.168.1.0/24, the destination-EID for the Map-Request is 192.168.1.0. The source-EID address for the Map-Request will also be 192.168.1.0 (in this example) and the Map-Request is sent to the configured Map-Resolver. If the Map-Resolver and Map-Server are the same LISP system, then the "lig self" is testing if the Map-Resolver can "turn back a Map-Request to the site". If another Map-Resolver is used, it can test that the site's EID-prefix has been injected into the ALT infrastructure in which case the lig Map-Request is processed by the Map-Resolver, propagated through each ALT router hop to the site's registered Map-Server. Then the Map-Server returns the Map-Request to originating site. In which case, an xTR at the originating site sends a Map-Reply to the source of the Map-Request (could be itself or another xTR for the site). All other command parameters are described above. Using "lig self6" tests for registering of IPv6 EID- prefixes. Some sample output for ligging yourself: rutile# lig self Send loopback map-request to 10.0.0.1 for 192.168.2.0 ... Received map-reply from 10.0.0.3 with rtt 0.001592 secs Map-cache entry for EID 192.168.2.0: 192.168.2.0/24, uptime: 00:00:02, expires: 23:59:57 via map-reply, self Locator Uptime State Priority/Weight Packets In/Out 10.0.0.3 00:00:02 up 1/100 0/0 titanium-simlo# lig self6 Send loopback map-request to 10.0.0.1 for 192:168:1:: ... Received map-reply from 10::1 with rtt 0.044372 secs Map-cache entry for EID 192:168:1::: 192:168:1::/48, uptime: 00:00:01, expires: 23:59:58 via map-reply, self Locator Uptime State Priority/Weight Packets In/Out 10.0.0.3 00:00:01 up 1/100 0/0 10::1 00:00:01 up 2/0 0/0 5.2. Public Domain Host Implementation There is a public domain implementation that can run on any x86 based system. The only requirement is that the system that initiates lig must have an address assigned from the locator namespace. Farinacci & Meyer Expires August 13, 2010 [Page 10] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 lig [-d] -m [-c ] [-t ] Parameter description: -d: prints additional protocol debug output. : is the destination EID or FQDN of a LISP host. -m : is the RLOC address or FQDN of a Map-Resolver. -c : the number of Map-Requests to send before the first Map- Reply is returned. The default value is 3. The range is from 1 to 5. -t : the amount of time, in seconds, before another Map- Request is sent when no Map-Reply is returned. The default value is 2 seconds. The range is from 1 to 5. Some sample output: % lig titanium-test.lisp4.net -m 10.0.0.1 Send map-request to 10.0.0.1 for 192.168.1.1 ... Received map-reply from 10.0.0.2 with rtt 0.04000 sec Mapping entry for EID 192.168.1.1: 192.168.1.0/24, record ttl: 60 Locator State Priority/Weight 10.0.0.1 up 1/25 10.0.0.2 up 1/25 10.0.0.3 up 1/25 10.0.0.4 up 2/25 The public domain implementation of lig is available at http://github.com/davidmeyer/lig. Farinacci & Meyer Expires August 13, 2010 [Page 11] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 6. Testing the ALT There are cases where a Map-Reply is returned from a lig request but the user doesn't really know how much of the mapping infrastructure was tested. There are two cases to consider, avoiding the ALT and traversing the ALT. When an ITR sends a lig request to its Map-Resolver for a destination-EID, the Map-Resolver could also be configured as a Map- Server. And if the destination-EID is for a site that registers with this Map-Server, the Map-Request is sent to the site directly without testing the ALT. This occurs because the Map-Server is the source of the advertisement for the site's EID-prefix. So if the map-reply is returned to the lig requesting site, you cannot be sure that other sites can reach the same destination-EID. If a Map-Resolver is used that is not a Map-Server for the EID-prefix being sought, then the ALT infrastructure can be tested. This test case is testing the functionality of the Map-Resolver, traversal of the ALT (testing BGP-over-GRE), and the Map-Server. It is recommended that users issue 2 lig requests, each which send Map-Requests to different Map-Resolvers. The network can have a LISP-ALT router deployed as a "ALT looking- glass" node. This type of router has BGP peering sessions with other ALT routers where it does not inject any EID-prefixes into the ALT but just learns ones advertised by other ALT routers and Map-Servers. This router is configured as a Map-Resolver. Lig users can point to the ALT looking-glass router for Map-Resolver services via the "to " parameter on the lig command. The ALT looking-glass node can be used to lig other sites as well as your own site. When the ALT looking-glass is used as a Map-Resolver, you can be assured the ALT network is being tested. Farinacci & Meyer Expires August 13, 2010 [Page 12] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 7. Future Enhancements When negative Map-Replies have been further developed and implemented, lig should be modified appropriately to process and clearly indicate how and why a negative Map-Reply was received. Negative Map-Replies could be sent in the following cases, the lig request was initiated for a non-EID address or the Map-Request initiated by lig request is being rejected due to rate-limiting on the replier. Farinacci & Meyer Expires August 13, 2010 [Page 13] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 8. Deployed Network Diagnostic Tools There is an web-based interface to do auto-polling with lig on the back-end for most of the LISP sites on the LISP test network. The web-page can be accessed at http://www.lisp4.net/status. There is a LISP site monitoring web-based interface that can be found at http://www.lisp4.net/lisp-site. At http://baldomar.ccaba.upc.edu/lispmon, written by the folks at UPC, shows a geographical map indicating where each LISP site resides. Farinacci & Meyer Expires August 13, 2010 [Page 14] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 9. Security Considerations The use of lig does not affect the security of the LISP infrastructure as it is simply a tool that facilities diagnostic querying. See [LISP], [ALT], and [LISP-MS] for descriptions of the security properties of the LISP infrastructure. Farinacci & Meyer Expires August 13, 2010 [Page 15] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 10.2. Informative References [ALT] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "LISP Alternative Topology (LISP-ALT)", draft-ietfr-lisp-alt-03.txt (work in progress), February 2010. [CONS] Farinacci, D., Fuller, V., and D. Meyer, "LISP-CONS: A Content distribution Overlay Network Service for LISP", draft-meyer-lisp-cons-03.txt (work in progress), November 2007. [LISP] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "Locator/ID Separation Protocol (LISP)", draft-ietf-lisp-06.txt (work in progress), January 2010. [LISP-MS] Farinacci, D. and V. Fuller, "LISP Map Server", draft-ietf-lisp-ms-04.txt (work in progress), October 2009. [NERD] Lear, E., "NERD: A Not-so-novel EID to RLOC Database", draft-lear-lisp-nerd-04.txt (work in progress), April 2008. Farinacci & Meyer Expires August 13, 2010 [Page 16] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 Appendix A. Acknowledgments Thanks and kudos to John Zwiebel, Andrew Partan, Darrel Lewis, and Vince Fuller for providing critical feedback on the lig design and prototype implementations. These folks as well as all the people on lisp-beta@external.cisco.com who tested lig functionality and continue to do so, we extend our sincere thanks. Farinacci & Meyer Expires August 13, 2010 [Page 17] =0C Internet-Draft LISP Internet Groper (LIG) February 2010 Authors' Addresses Dino Farinacci cisco Systems Tasman Drive San Jose, CA 95134 USA Email: dino@cisco.com Dave Meyer cisco Systems 170 Tasman Drive San Jose, CA USA Email: dmm@cisco.com Farinacci & Meyer Expires August 13, 2010 [Page 18] =0C --Apple-Mail-2--332133380 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit --Apple-Mail-2--332133380 Content-Disposition: attachment; filename=rfcdiff-lisp-lig-01-to-02.html Content-Type: text/html; x-unix-mode=0600; name="rfcdiff-lisp-lig-01-to-02.html" Content-Transfer-Encoding: 7bit wdiff draft-farinacci-lisp-lig-01.txt draft-farinacci-lisp-lig-02.txt 
Network Working Group                                       D. Farinacci
Internet-Draft                                                  D. Meyer
Intended status: Experimental                              cisco Systems
Expires: November 6, 2009                                    May 5, 2009 August 13, 2010                                February 9, 2010

                       LISP Internet Groper (LIG)
                    draft-farinacci-lisp-lig-01.txt
                    draft-farinacci-lisp-lig-02.txt

Abstract

   A simple tool called the LISP Internet Groper or 'lig' can be used to
   query the LISP mapping database.  This draft describes how it works.

Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   This Internet-Draft will expire on November 6, 2009. August 13, 2010.

Copyright Notice

   Copyright (c) 2009 2010 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 (http://trustee.ietf.org/license-info). document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Abstract

   A simple tool called  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the LISP Internet Groper or 'lig' can be used to
   query Trust Legal Provisions and are provided without warranty as
   described in the LISP mapping database.  This draft describes how it works. BSD License.

Table of Contents

   1.  Requirements Notation  . . . . . . . . . . . . . . . . . . . .  3
   2.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Definition of Terms  . . . . . . . . . . . . . . . . . . . . .  5
   4.  Basic Overview . . . . . . . . . . . . . . . . . . . . . . . .  7
   5.  Implementation Details . . . . . . . . . . . . . . . . . . . .  9
     5.1.  LISP Router Implementation . . . . . . . . . . . . . . . .  9
     5.2.  Public Domain Host Implementation  . . . . . . . . . . . . 10
   6.  Testing the ALT  . . . . . . . . . . . . . . . . . . . . . . . 12
   7.  Future Enhancements  . . . . . . . . . . . . . . . . . . . . . 13
   8.  Deployed Network Diagnostic Tools  . . . . . . . . . . . . . . 14
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 14
   9. 15
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     9.1. 16
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 15
     9.2. 16
     10.2. Informative References . . . . . . . . . . . . . . . . . . 15 16
   Appendix A.  Acknowledgments . . . . . . . . . . . . . . . . . . . 16 17
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 18

1.  Requirements Notation

   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 [RFC2119].

2.  Introduction

   LISP [LISP] specifies an architecture and mechanism for replacing the
   addresses currently used by IP with two separate name spaces:
   Endpoint IDS (EIDs), used within sites, and Routing Locators (RLOCs),
   used on the transit networks that make up the Internet
   infrastructure.  To achieve this separation, the Locator/ID
   Separation Protocol (LISP) defines protocol mechanisms for mapping
   from EIDs to RLOCs.  In addition, LISP assumes the existence of a
   database to store and propagate those mappings globally.  Several
   such databases have been proposed, among them: LISP-CONS [CONS],
   LISP-NERD [NERD], and LISP+ALT [ALT], with LISP+ALT being the system
   that is currently being implemented and deployed on the pilot LISP
   network.

   In conjunction with the various mapping systems, there exists a
   network based API called LISP Map-Server [LISP-MS].  Using Map
   Resolvers and Map Servers allows LISP sites to query and register
   into the database in a uniform way independent of the mapping system
   used.  Sending Map-Requests to Map Resolvers provides a secure
   mechanism mechanism to obtain a Map-Reply containing the
   authoritative EID-to-RLOC mapping for a destination LISP site.

   The 'lig' is a manual management tool to query the mapping database.
   It can be run by all devices which implement LISP, including ITRs,
   ETRs, PTR, Map-Resolvers, Map-Servers, and LISP-ALT routers, as well
   as by a host system at either a LISP-capable or non-LISP-capable
   site.

3.  Definition of Terms

   Map-Server:   a network infrastructure component which learns EID-to-
      RLOC mapping entries from an authoritative source (typically, an
      ETR, though static configuration or another out-of-band mechanism
      may be used).  A Map-Server advertises these mappings in the
      distributed mapping database.

   Map-Resolver:   a network infrastructure component which accepts LISP
      Encapsulated Map-Requests, typically from an ITR, quickly
      determines whether or not the destination IP address is part of
      the EID namespace; if it is not, a Negative Map-Reply is
      immediately returned.  Otherwise, the Map-Resolver finds the
      appropriate EID-to-RLOC mapping by consulting the distributed
      mapping database system.

   Routing Locator (RLOC):   the IPv4 or IPv6 address of an egress
      tunnel router (ETR).  It is the output of a EID-to-RLOC mapping
      lookup.  An EID maps to one or more RLOCs.  Typically, RLOCs are
      numbered from topologically-aggregatable blocks that are assigned
      to a site at each point to which it attaches to the global
      Internet; where the topology is defined by the connectivity of
      provider networks, RLOCs can be thought of as PA addresses.
      Multiple RLOCs can be assigned to the same ETR device or to
      multiple ETR devices at a site.

   Endpoint ID (EID):   a 32-bit (for IPv4) or 128-bit (for IPv6) value
      used in the source and destination address fields of the first
      (most inner) LISP header of a packet.  The host obtains a
      destination EID the same way it obtains an destination address
      today, for example through a DNS lookup or SIP exchange.  The
      source EID is obtained via existing mechanisms used to set a
      host's "local" IP address.  An EID is allocated to a host from an
      EID-prefix block associated with the site where the host is
      located.  An EID can be used by a host to refer to other hosts.
      EIDs MUST NOT be used as LISP RLOCs.  Note that EID blocks may be
      assigned in a hierarchical manner, independent of the network
      topology, to facilitate scaling of the mapping database.  In
      addition, an EID block assigned to a site may have site-local
      structure (subnetting) for routing within the site; this structure
      is not visible to the global routing system.

   EID-to-RLOC Cache:   a short-lived, on-demand table in an ITR that
      stores, tracks, and is responsible for timing-out and otherwise
      validating EID-to-RLOC mappings.  This cache is distinct from the
      full "database" of EID-to-RLOC mappings, it is dynamic, local to
      the ITR(s), and relatively small while the database is
      distributed, relatively static, and much more global in scope.

   EID-to-RLOC Database:   a global distributed database that contains
      all known EID-prefix to RLOC mappings.  Each potential ETR
      typically contains a small piece of the database: the EID-to-RLOC
      mappings for the EID prefixes "behind" the router.  These map to
      one of the router's own, globally-visible, IP addresses.

   Encapsulated Map-Request (EMR):   an EMR is a Map-Request message
      which is encapsulated with another LISP header using UDP
      destination port number 4341.  It is used so an ITR, PTR, or a
      system initiating a 'lig' command can get the Map-Request to a
      Map-Resolver by using locater addresses.  When the Map-Request is
      decapsulated by the Map-Resolver it will be forwarded on the ALT
      network to the Map-Server that has injected the EID-prefix for a
      registered site.  The Map-Server will then encapsulate the Map-
      Request in a LISP packet and send it to an an ETR at the site.
      The ETR will then return an authoritative reply to the system that
      initiated the request.

4.  Basic Overview

   When the lig command is run, a Map-Request is sent for a destination
   EID.  When a Map-Reply is returned, the contents are displayed to the
   user.  The information displayed includes:

   o  The EID-prefix for the site the queried destination EID matches.

   o  The locator address of the Map Replier.

   o  The locator-set for the mapping entry which includes the locator
      address, up/down status, priority, and weight of each locator.

   o  An round-trip-time estimate for the Map-Request/Map-Reply
      exchange.

   A possible syntax for a lig command could be:

       lig <destination> [source <source>] [to <map-resolver>]

   Parameter description:

   <destination>:  is either a Fully Qualified Domain Name or a
      destination EID for a remote LISP site.

   source <source>:  is an optional source EID to be inserted in the
      "Source EID" field of the Map-Request.

   to <map-resolver>:  is an optional Fully Qualified Domain Name or
      RLOC address for a Map-Resolver.

   The lig utility has two usage cases.  The first being a way to query
   the mapping database for a particular EID.  And the other to verify
   if a site has registered successfully with a Map-Server.

   The first usage has already been described.  Verifying registration
   is called "ligging yourself".  What occurs is in the lig initiator, a
   Map-Request is sent for one of the EIDs for the lig initiator's site.
   The Map-Request is then returned to one of the ETRs for the lig
   initiating site.  In response to the Map-Request, a Map-Reply is sent
   back to the locator address of the lig initiator (note the Map-Reply
   could be sent by the lig initiator).  That Map-Reply is processed and
   the mapping data for lig initiating site is displayed for the user.
   Refer to the syntax in section Section 5.1 for an implementation of
   "ligging yourself".  However, for host-based implementations within a
   LISP site, "lig self" is less useful since the host may not have an
   RLOC to receive a Map-Reply with.  But, lig can be used in a non-LISP
   site as well as from infrastructure hosts to get mapping information.

5.  Implementation Details

5.1.  LISP Router Implementation

   The cisco LISP prototype implementation has support for lig for IPv4
   and IPv6.  The command line description is:

       lig <dest-eid> [source <source-eid>] [to <mr>] [count <1-5>]

   This command initiates the LISP Internet Groper.  It is similar to
   the DNS analogue 'dig' but works on the LISP mapping database.  When
   this command is invoked, the local system will send a Map-Request to
   the configured Map-Resolver.  When a Map-Reply is returned, its
   contents will be displayed to the user.  By default, up to 3 Map-
   Requests are sent if no Map-Reply is returned but once a Map-Reply is
   returned no other Map-Requests are sent.  The destination can take a
   DNS name, or an IPv4 or IPv6 EID address.  The <source-eid> can be
   one of the EID addresses assigned to the site in the default VRF.
   When <mr> is specified, then the Map-Request is sent to the address.
   Otherwise, the Map-Request is sent to a configured Map-Resolver.
   When a Map-Resolver is not configured then the Map-Request is sent on
   the ALT network if the local router is attached to the ALT.  When
   "count <1-5>" is specified, 1, 2, 3, 4, or 5 Map-Requests are sent.

   Some sample output:

     titanium-dino# lig titanium-dmm.lisp4.net
     Send map-request to 10.0.0.1 for 192.168.1.1 ...
     Received map-reply from 10.0.0.2 with rtt 0.081468 secs

     Map-cache entry for titanium-dmm.lisp4.net EID 192.168.1.1:
     192.168.1.0/24, uptime: 13:59:59, expires: 23:59:58,
                     via map-reply, auth
       Locator          Uptime    State  Priority/Weight  Packets In/Out
       10.0.0.2         13:59:59  up     1/100            0/14

   Using lig to "lig yourself" is accomplished with the following
   syntax:

       lig {self | self6} [source <source-eid>] [to <mr>] [count <1-5>]

   Use this command for a simple way to see if the site is registered
   with the mapping database system.  The destination-EID address for
   the Map-Request will be the first configured EID-prefix for the site
   (with the host-bits set to 0).  For example, if the site's EID-prefix
   is 192.168.1.0/24, the destination-EID for the Map-Request is
   192.168.1.0.  The source-EID address for the Map-Request will also be
   192.168.1.0 (in this example) and the Map-Request is sent to the
   configured Map-Resolver.  If the Map-Resolver and Map-Server are the
   same LISP system, then the "lig self" is testing if the Map-Resolver
   can "turn back a Map-Request to the site".  If another Map-Resolver
   is used, it can test that the site's EID-prefix has been injected
   into the ALT infrastructure in which case the lig Map-Request is
   processed by the Map-Resolver, propagated through each ALT router hop
   to the site's registered Map-Server.  Then the Map-Server returns the
   Map-Request to originating site.  In which case, an xTR at the
   originating site sends a Map-Reply to the source of the Map-Request
   (could be itself or another xTR for the site).  All other command
   parameters are described above.  Using "lig self6" tests for
   registering of IPv6 EID- prefixes.

   Some sample output for ligging yourself:

     rutile# lig self
     Send loopback map-request to 10.0.0.1 for 192.168.2.0 ...
     Received map-reply from 10.0.0.3 with rtt 0.001592 secs

     Map-cache entry for EID 192.168.2.0:
     192.168.2.0/24, uptime: 00:00:02, expires: 23:59:57
                     via map-reply, self
       Locator       Uptime    State  Priority/Weight  Packets In/Out
       10.0.0.3      00:00:02  up     1/100            0/0

     titanium-simlo# lig self6
     Send loopback map-request to 10.0.0.1 for 192:168:1:: ...
     Received map-reply from 10::1 with rtt 0.044372 secs

     Map-cache entry for EID 192:168:1:::
     192:168:1::/48, uptime: 00:00:01, expires: 23:59:58
                        via map-reply, self
       Locator          Uptime    State  Priority/Weight  Packets In/Out
       10.0.0.3         00:00:01  up     1/100            0/0
       10::1            00:00:01  up     2/0              0/0

5.2.  Public Domain Host Implementation

   There is a public domain implementation that can run on any x86 based
   system.  The only requirement is that the system that initiates lig
   must have an address assigned from the locator namespace.

       lig [-d] <eid> -m <map-resolver> [-c <count>] [-t <timeout>]

   Parameter description:

   -d:  prints additional protocol debug output.

   <eid>:  is the destination EID or FQDN of a LISP host.

   -m <map-resolver>:  is the RLOC address or FQDN of a Map-Resolver.

   -c <count>:  the number of Map-Requests to send before the first Map-
      Reply is returned.  The default value is 3.  The range is from 1
      to 5.

   -t <timeout>:  the amount of time, in seconds, before another Map-
      Request is sent when no Map-Reply is returned.  The default value
      is 2 seconds.  The range is from 1 to 5.

   Some sample output:

     % lig titanium-test.lisp4.net -m 10.0.0.1
     Send map-request to 10.0.0.1 for 192.168.1.1 ...
     Received map-reply from 10.0.0.2 with rtt 0.04000 sec

     Mapping entry for EID 192.168.1.1:
     192.168.1.0/24, record ttl: 60
      Locator           State     Priority/Weight
      10.0.0.1          up        1/25
      10.0.0.2          up        1/25
      10.0.0.3          up        1/25
      10.0.0.4          up        2/25

   The public domain implementation of lig is available at
   sourceforge.net.
   http://github.com/davidmeyer/lig.

6.  Testing the ALT

   There are cases where a Map-Reply is returned from a lig request but
   the user doesn't really know how much of the mapping infrastructure
   was tested.  There are two cases to consider, avoiding the ALT and
   traversing the ALT.

   When an ITR sends a lig request to its Map-Resolver for a
   destination-EID, the Map-Resolver could also be configured as a Map-
   Server.  And if the destination-EID is for a site that registers with
   this Map-Server, the Map-Request is sent to the site directly without
   testing the ALT.  This occurs because the Map-Server is the source of
   the advertisement for the site's EID-prefix.  So if the map-reply is
   returned to the lig requesting site, you cannot be sure that other
   sites can reach the same destination-EID.

   If a Map-Resolver is used that is not a Map-Server for the EID-prefix
   being sought, then the ALT infrastructure can be tested.  This test
   case is testing the functionality of the Map-Resolver, traversal of
   the ALT (testing BGP-over-GRE), and the Map-Server.

   It is recommended that users issue 2 lig requests, each which send
   Map-Requests to different Map-Resolvers.

   The network can have a LISP-ALT router deployed as a "ALT looking-
   glass" node.  This type of router has BGP peering sessions with other
   ALT routers where it does not inject any EID-prefixes into the ALT
   but just learns ones advertised by other ALT routers and Map-Servers.
   This router is configured as a Map-Resolver.  Lig users can point to
   the ALT looking-glass router for Map-Resolver services via the "to
   <map-resolver>" parameter on the lig command.  The ALT looking-glass
   node can be used to lig other sites as well as your own site.  When
   the ALT looking-glass is used as a Map-Resolver, you can be assured
   the ALT network is being tested.

7.  Future Enhancements

   When negative Map-Replies have been further developed and
   implemented, lig should be modified appropriately to process and
   clearly indicate how and why a negative Map-Reply was received.
   Negative Map-Replies could be sent in the following cases, the lig
   request was initiated for a non-EID address or the Map-Request
   initiated by lig request is being rejected due to rate-limiting on
   the replier.

8.  Deployed Network Diagnostic Tools

   There is an web-based interface to do auto-polling with lig on the
   back-end for most of the LISP sites on the LISP test network.  The
   web-page can be accessed at http://www.lisp4.net/status.

   There is a LISP site monitoring web-based interface that can be found
   at http://www.lisp4.net/lisp-site.

   At http://baldomar.ccaba.upc.edu/lispmon, written by the folks at
   UPC, shows a geographical map indicating where each LISP site
   resides.

9.  Security Considerations

   The use of lig does not affect the security of the LISP
   infrastructure as it is simply a tool that facilities diagnostic
   querying.  See [LISP], [ALT], and [LISP-MS] for descriptions of the
   security properties of the LISP infrastructure.

9.

10.  References

9.1.

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

9.2.

10.2.  Informative References

   [ALT]      Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "LISP
              Alternative Topology (LISP-ALT)",
              draft-fuller-lisp-alt-03.txt
              draft-ietfr-lisp-alt-03.txt (work in progress),
              February 2009. 2010.

   [CONS]     Farinacci, D., Fuller, V., and D. Meyer, "LISP-CONS: A
              Content distribution Overlay Network  Service for LISP",
              draft-meyer-lisp-cons-03.txt (work in progress),
              November 2007.

   [LISP]     Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,
              "Locator/ID Separation Protocol (LISP)",
              draft-farinacci-lisp-12.txt
              draft-ietf-lisp-06.txt (work in progress),
              March 2009. January 2010.

   [LISP-MS]  Farinacci, D. and V. Fuller, "LISP Map Server",
              draft-fuller-lisp-ms-00.txt
              draft-ietf-lisp-ms-04.txt (work in progress),
              March
              October 2009.

   [NERD]     Lear, E., "NERD: A Not-so-novel EID to RLOC Database",
              draft-lear-lisp-nerd-04.txt (work in progress),
              April 2008.

Appendix A.  Acknowledgments

   Thanks and kudos to John Zwiebel, Andrew Partan, Darrel Lewis, and
   Vince Fuller for providing critical feedback on the lig design and
   prototype implementations.  These folks as well as all the people on
   lisp-beta@external.cisco.com who tested lig functionality and
   continue to do so, we extend our sincere thanks.

Authors' Addresses

   Dino Farinacci
   cisco Systems
   Tasman Drive
   San Jose, CA  95134
   USA

   Email: dino@cisco.com

   Dave Meyer
   cisco Systems
   170 Tasman Drive
   San Jose, CA
   USA

   Email: dmm@cisco.com
--Apple-Mail-2--332133380 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit --Apple-Mail-2--332133380-- From darlewis@cisco.com Fri Feb 12 15:15:38 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 552733A790F for ; Fri, 12 Feb 2010 15:15:38 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -6.032 X-Spam-Level: X-Spam-Status: No, score=-6.032 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, HTML_MESSAGE=0.001, J_CHICKENPOX_39=0.6, MANGLED_SAVELE=2.3, RCVD_IN_DNSWL_HI=-8, SARE_HTML_SINGLETS=1.666] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id qQ8+sK+Nr0EL for ; Fri, 12 Feb 2010 15:15:31 -0800 (PST) Received: from sj-iport-5.cisco.com (sj-iport-5.cisco.com [171.68.10.87]) by core3.amsl.com (Postfix) with ESMTP id 990DD3A67D1 for ; Fri, 12 Feb 2010 15:15:31 -0800 (PST) Authentication-Results: sj-iport-5.cisco.com; dkim=neutral (message not signed) header.i=none X-Files: draft-ietf-lisp-Interworking-00-to-01-diff.html, draft-ietf-lisp-interworking-01.txt : 61649, 47428 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEAP5vdUurRN+J/2dsb2JhbACbDnSnRoo8jRCCVIIEBIMT X-IronPort-AV: E=Sophos;i="4.49,463,1262563200"; d="txt'?html'217?scan'217,208,217";a="150755415" Received: from sj-core-3.cisco.com ([171.68.223.137]) by sj-iport-5.cisco.com with ESMTP; 12 Feb 2010 23:16:50 +0000 Received: from [10.21.74.176] ([10.21.74.176]) by sj-core-3.cisco.com (8.13.8/8.14.3) with ESMTP id o1CNGohV001967 for ; Fri, 12 Feb 2010 23:16:50 GMT From: Darrel Lewis Content-Type: multipart/mixed; boundary=Apple-Mail-6--53398945 Date: Fri, 12 Feb 2010 15:16:49 -0800 Message-Id: <5D6E81D4-77A1-4A20-B8AD-664F9316A969@cisco.com> To: lisp@ietf.org Mime-Version: 1.0 (Apple Message framework v1077) X-Mailer: Apple Mail (2.1077) Subject: [lisp] Proposed draft-ietf-lisp-interworking-01 draft X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Feb 2010 23:15:38 -0000 --Apple-Mail-6--53398945 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Here is an updated version of the LISP Interworking specification that = I'd like to publish to the Internet Drafts repository. The main addition to the draft is a the introduction of an optional = network element called the "Proxy Egress Tunnel Router" or PETR. =20 Both html diffs and the full text of the new draft are attached. Comments appreciated. I'd like to get this posted next Friday (by Feb 22nd). -Darrel (for the other Interworking authors: Dino, Dave, and Vince) --Apple-Mail-6--53398945 Content-Disposition: attachment; filename=draft-ietf-lisp-Interworking-00-to-01-diff.html Content-Type: text/html; name="draft-ietf-lisp-Interworking-00-to-01-diff.html" Content-Transfer-Encoding: 7bit wdiff draft-ietf-lisp-interworking-00.txt draft-ietf-lisp-interworking-01.txt 
Network Working Group                                           D. Lewis
Internet-Draft                                                  D. Meyer
Intended status: Experimental                               D. Farinacci
Expires: November 27, 2009 August 16, 2010                                       V. Fuller
                                                     Cisco Systems, Inc.
                                                            May 26, 2009
                                                       February 12, 2010

                  Interworking LISP with IPv4 and IPv6
                    draft-ietf-lisp-interworking-00
                  draft-ietf-lisp-interworking-01.txt

Abstract

   This document describes techniques for allowing sites running the
   Locator/ID Separation Protocol (LISP [LISP]) to interoperate with
   Internet sites (using either IPv4, IPv6, or both) which are not
   running LISP.  A fundamental property of LISP speaking sites is that
   they use Endpoint Identifiers (EIDs), rather than traditional IP
   addresses, in the source and destination fields of all traffic they
   emit or receive.  While EIDs are syntactically identical to IPv4 or
   IPv6 addresses, routes for them are not carried in the global routing
   system so an interoperability mechanism is needed for non-LISP-
   speaking sites to exchange traffic with LISP-speaking sites.  This
   document introduces three such mechanisms: the first uses a new
   network element, the LISP Proxy Ingress Tunnel Routers (PITR)
   (Section 5) to act as a intermediate LISP Ingress Tunnel Router (ITR)
   for non-LISP-speaking hosts while the second adds Network Address
   Translation (NAT) functionality to LISP Ingress and LISP Egress
   Tunnel Routers (xTRs) to substitute routable IP addresses for non-
   routable EIDs.  Finally, this document introduces a Proxy Egress
   Tunnel Router (PETR) to solve cases where a LISP site cannot send a
   packet which has as its source address a non-routable EID

Status of this Memo

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

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

   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."
   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on November 27, 2009. August 16, 2010.

Copyright Notice

   Copyright (c) 2009 2010 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 (http://trustee.ietf.org/license-info). document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Abstract

   This  Code Components extracted from this document describes techniques for allowing sites running the
   Locator/ID Separation Protocol (LISP [LISP]) to interoperate with
   Internet sites not running LISP.  A fundamental property of LISP-
   speaking sites is that they use Endpoint Identifiers (EIDs), rather
   than traditional IP addresses, must
   include Simplified BSD License text as described in Section 4.e of
   the source Trust Legal Provisions and destination fields
   of all traffic they emit or receive.  While EIDs are syntactically
   identical to IP addresses, routes for them are not carried in the
   global routing system so an interoperability mechanism is needed for
   non-LISP-speaking sites to exchange traffic with LISP-speaking sites.
   This document introduces two such mechanisms: the first uses a new
   network element, the LISP Proxy Tunnel Router (PTR) (Section 5) to
   act provided without warranty as a intermediate LISP Ingress Tunnel Router (ITR) for non-LISP-
   speaking hosts while
   described in the second adds Network Address Translation
   (NAT) functionality to LISP Ingress and LISP Egress Tunnel Routers
   (xTRs) to substitute routable IP addresses for non-routable EIDs. BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3  4
   2.  LISP Interworking Models . . . . . . . . . . . . . . . . . . .  3  6
   3.  Definition of Terms  . . . . . . . . . . . . . . . . . . . . .  5  8
   4.  Routable EIDs  . . . . . . . . . . . . . . . . . . . . . . . .  6
     4.1. 11
   5.  Impact on Routing Table  . . . . . . . . . . . . . . . . .  6
     4.2. . . 12
   6.  Requirement for using BGP  . . . . . . . . . . . . . . . .  6
     4.3. . . 13
   7.  Limiting the Impact of Routable EIDs . . . . . . . . . . .  6
     4.4. . . 14
   8.  Use of Routable EIDs for Testing LISP  . . . . . . . . . .  7
   5. . . 15
   9.  Proxy Ingress Tunnel Routers . . . . . . . . . . . . . . . . . . . . .  7
     5.1.  PTR 16
   10. PITR EID announcements . . . . . . . . . . . . . . . . . .  7
     5.2. . . 17
   11. Packet Flow with PTRs PITRs . . . . . . . . . . . . . . . . . .  8
     5.3. . . 18
   12. Scaling PTRs PITRs  . . . . . . . . . . . . . . . . . . . . . . .  9
     5.4. . 20
   13. Impact of the PTRs PITRs placement in the network . . . . . . .  9
     5.5. . . 21
   14. Benefit to Networks Deploying PTRs PITRs  . . . . . . . . . . . .  9
   6. . 22
   15. LISP-NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     6.1. 23
     15.1.  LISP-NAT for LISP-NR addressed hosts  . . . . . . . . . . . 10
     6.2. 23
     15.2.  LISP Sites with Hosts using RFC 1918 Addresses
            Sending to non-LISP Sites . . . . . . . . . . . . . . . . . . . . 11
     6.3. 24
     15.3.  LISP Sites with Hosts using RFC 1918 Addresses
            Communicating to Other LISP Sites . . . . . . . . . . . . 11
     6.4. 24
     15.4.  LISP-NAT and multiple EIDs  . . . . . . . . . . . . . . . . 12
     6.5. 25
     15.5.  When LISP-NAT and PTRs Together PITRs used by the same LISP Site  . . . 25
   16. Proxy Egress Tunnel Routers  . . . . . . . . . . . . . . . 12
   7. . . 27
     16.1.  Packet Flow with Proxy Egress Tunnel Routers  . . . . . . 27
   17. Discussion of Proxy ITRs (PITRs), LISP-NAT, and Proxy-ETRs
       (PETRs)  . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
   18. How Proxy-ITRs and Proxy-ETRs Interact . . . . . . . . . . . . 30
   19. Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   8. 31
   20. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 13
   9. 32
   21. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 14
   10. 33
   22. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     10.1. 34
     22.1.  Normative References  . . . . . . . . . . . . . . . . . . . 14
     10.2. 34
     22.2.  Informative References  . . . . . . . . . . . . . . . . . . 14 34
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 35

1.  Introduction

   This document describes two mechanisms for interoperation between
   LISP [LISP] sites, which use non-globally-routed EIDs, and non-LISP
   sites: use of PTRs, PITRs, which create highly-aggregated routes to EID
   prefixes for non-LISP sites to follow; and the follow.  The use of NAT by LISP ETRs
   when communicating with non-LISP hosts.  And finally the use of Proxy
   Egress Tunnel routers (PETRs) LISP for sites relying on PITRs and
   which are faced with certain restrictions.

   A key behavior of the separation of Locators and End-Point-IDs is
   that EID prefixes are not advertised to the Internet's Default Free
   Zone (DFZ).  Specifically, only RLOCs are carried in the Internet's
   DFZ.  Existing Internet sites (and their hosts) who do not
   participate in the LISP system must still be able to reach sites
   numbered from this non routed EID space.  This draft describes a set
   of mechanisms that can be used to provide reachability between sites
   that are LISP-capable and those that are not.  This document
   introduces two three such mechanisms: the mechanisms.  The first uses a new network
   element, the LISP Proxy Ingress Tunnel Router (PTR) (PITR) (Section 5) to
   act as a intermediate LISP Ingress Tunnel Router (ITR) for non-LISP-speaking
   hosts while the non-LISP-
   speaking hosts.  The second adds a form of Network Address
   Translation (NAT) functionality to Tunnel Routers (xTRs) to
   substitute routable IP addresses for non-routable EIDs.  The final
   network element is the LISP Proxy Egress Tunnel Routers (PETR), which
   act as an intermediate Egress Tunnel Router (ETR) for LISP sites who
   are using PITRs but need assistance in reaching non-LISP sites.

   More detailed descriptions of these mechanisms and the network
   elements involved may be found in the following sections:

   - Section 2 describes the different cases where interworking
   mechanisms are needed

   - Section 3 defines terms used throughout the document

   - Section 4 describes the relationship between the new EID prefix
   space and the IP address space used by the current Internet

   - Section 5 introduces and describes the operation of PTRs Proxy-ITRs

   - Section 6 defines how NAT is used by ETRs to translate non-routable
   EIDs into routable IP addresses.

   - Section 7 introduces and describes the operations of Proxy-ETRs

   - Section 8 describes the relationship between asymmetric and
   Symmetric interworking mechanisms (Proxy-ITRs and Proxy-ETRs vs LISP-
   NAT)

   Note that any successful interworking model should be independent of
   any particular EID-to-RLOC mapping algorithm.  This document does not
   comment on the value of any of the particular LISP mapping system. systems.

2.  LISP Interworking Models

   There are 4 unicast connectivity cases which describe how sites can
   communicate with each other:

   1.  Non-LISP site to Non-LISP site

   2.  LISP site to LISP site

   3.  LISP site to Non-LISP site

   4.  Non-LISP site to LISP site

   Note that while Cases 3 and 4 seem similar, there are subtle
   differences due to the way communications are originated.

   The first case is the Internet as we know it today and as such will
   not be discussed further here.  The second case is documented in
   [LISP] and, hence, there are no new interworking requirements because
   there are no new protocol requirements placed on intermediate non-
   LISP routers.

   In case 3, LISP site to Non-LISP site, a LISP site can (in most
   cases) send packets to a non-LISP site because the non-LISP site
   prefixes are routable.  The non-LISP site need not do anything new to
   receive packets.  The only action the LISP site needs (with two
   possible caveats introduced below) to take is to know when not to LISP-
   encapsulate
   LISP-encapsulate packets.  This can be achieved via two mechanisms:

   1.  At the ITR in the source site, if the destination of an IP packet
       is found to match a prefix from the BGP routing table, then the
       site is directly reachable by the BGP core that exists and
       operates today.

   2.  Second, if (from the perspective of the ITR at the source site)
       the destination address of an IP address is not found in the EID-
       to-RLOC mapping database, the ITR could infer that it is not a
       LISP-capable site, and decide to not LISP-encapsulate the packet.

   3.  There are two potential caveats involved with Case 3, where there
       could be some situations where (unencapsualted) packets
       originated by a LISP site may not be forwarded to a non-LISP
       site.  One of these caveats (uRPF check failure) are detailed in
       Section 9 (Security Considerations).  The second caveat (protocol
       traversal) is reviewed in section 7, (Proxy-Egress Tunnel
       Routers).

   Case 4, typically the most challenging, occurs when a host at a non-LISP non-
   LISP site wishes to send traffic to a host at a LISP site.  If the
   source host uses a (non-globally-routable) EID as the destination IP
   address, the packet is forwarded inside the source site until it
   reaches a router which cannot forward it, at which point the traffic
   is dropped.  For traffic not to be dropped, either some route must be
   exist for the destination EID outside of LISP-speaking part of the
   network or an alternate mechanism must be in place.  Section 5 (PTRs)
   (PITRs) and Section 6 (LISP-NAT) describe two such mechanisms.

   Note that case 4 includes packets returning to the LISP Site in case
   3.

3.  Definition of Terms

   Endpoint ID (EID):  Endpoint ID (EID): A 32- 32-bit (for IPv4) or 128-bit
      (for IPv6) value used in the source and destination address fields
      of the first (most inner) LISP header of a packet.  A packet that is emitted by  The host
      obtains a system contains EIDs in its
      headers and LISP headers are prepended only when destination EID the packet
      reaches same way it obtains an Ingress Tunnel Router (ITR) on the data path to the destination EID.

   EID-Prefix Aggregate:  A set of EID-prefixes said
      address today, for example through a DNS lookup or SIP exchange.
      The source EID is obtained via existing mechanisms used to be aggregatable
      in the [RFC4632] sense.  That is, an EID-Prefix aggregate set a
      host's "local" IP address.  An EID is
      defined allocated to be a single contiguous power-of-two host from an
      EID-prefix block.
      Such a block associated with the site where the host is characterized
      located.  An EID can be used by a prefix and host to refer to other hosts.
      EIDs MUST NOT be used as LISP RLOCs.  Note that EID blocks may be
      assigned in a length.

   Routing Locator (RLOC):  An IP address hierarchical manner, independent of a LISP tunnel router.  It
      is the output network
      topology, to facilitate scaling of a the mapping database.  In
      addition, an EID block assigned to a site may have site-local
      structure (subnetting) for routing within the site; this structure
      is not visible to the global routing system.  When used in
      discussions with other Locator/ID separation proposals, a LISP EID
      will be called a "LEID".  Throughout this document, any references
      to "EID" refers to an LEID.

   EID-Prefix:  EID-prefix: A power-of-2 block of EIDs which are
      allocated to a site by an address allocation authority.  EID-
      prefixes are associated with a set of RLOC addresses which make up
      a "database mapping".  EID-prefix allocations can be broken up
      into smaller blocks when an RLOC set is to be associated with the
      smaller EID- prefix.  A globally routed address block (whether PI
      or PA) is not an EID-prefix.  However, a globally routed address
      block may be removed from global routing and reused as an EID-
      prefix.  A site that receives an explicitly allocated EID-prefix
      may not use that EID-prefix as a globally routed prefix assigned
      to RLOCs

   EID-Prefix Aggregate:  A set of EID-prefixes said to be aggregatable
      in the [RFC4632] sense.  That is, an EID-Prefix aggregate is
      defined to be a single contiguous power-of-two EID-prefix block.
      Such a block is characterized by a prefix and a length.  Provider
      Independent (PI) Addresses: an address block assigned from a pool
      where blocks are not associated with any particular location in
      the network (e.g. from a particular service provider), and is
      therefore not topologically aggregatable in the routing system.

   Routing Locator (RLOC):  The IPv4 or IPv6 address of an egress tunnel
      router (ETR).  It is the output of a EID-to-RLOC mapping lookup.
      An EID maps to one or more RLOCs.  Typically, RLOCs are numbered
      from topologically-
      aggregatable topologically-aggregatable blocks and that are assigned to a site
      at each point to which it attaches to the global Internet; where
      the topology is defined by the connectivity of provider networks,
      RLOCs can be thought of as Provider Aggregatable (PA) PA addresses.  Multiple RLOCs can be
      assigned to the same ETR device or to multiple ETR devices at a
      site.

   EID-to-RLOC Mapping:  A binding between an EID and the RLOC-set that
      can be used to reach the EID.  We use the term "mapping" in this
      document to refer to a EID-to-RLOC mapping.

   EID Prefix Reachability:  An EID prefix is said to be "reachable" if
      one or more of its locators are reachable.  That is, an EID prefix
      is reachable if the ETR (or its proxy) is reachable.

   Default Mapping:  A Default Mapping is a mapping entry for EID-prefix
      0.0.0.0/0.  It maps to a locator-set used for all EIDs in the
      Internet.  If there is a more specific EID-prefix in the mapping
      cache it overrides the Default Mapping entry.  The Default Mapping
      route can be learned by configuration or from a Map-Reply message
      [LISP].

   LISP Routable (LISP-R) Site:  A LISP site whose addresses are used as
      both globally routable IP addresses and LISP EIDs.

   LISP Non-Routable (LISP-NR) Site:  A LISP site whose addresses are
      EIDs only, these EIDs are not found in the legacy Internet routing
      table.

   LISP Proxy Ingress Tunnel Router (PTR):  PTRs (PITR):  PITRs are used to provide
      interconnectivity between sites which use LISP EIDs and those
      which do not.  They act as a gateway between the Legacy Internet
      and the LISP enabled Network.  A given PTR PITR advertises one or more
      highly aggregated EID prefixes into the public Internet and acts
      as the ITR for traffic received from the public Internet.  LISP
      Proxy Ingress Tunnel Routers are described in Section 5. 9.

   LISP Network Address Translation (LISP-NAT):  Network Address
      Translation between EID space assigned to a site and RLOC space
      also assigned to that site.  LISP Network Address Translation is
      described in Section 6.

    EID Sub Namespace:  A power-of-two block of aggregatable locators
      set aside for 15.

   LISP interworking.

4. Proxy Egress Tunnel Router (PETR):  PETRs are used to provide a
      LISP site's ITRs the ability to send traffic to non-LISP sites in
      cases where unencapsualted packets (the default mechanism) would
      fail to be delivered.  PETRs are implemented by having an ITR
      encapsulate all non-LISP destined traffic to a pre-configured
      PETR.  LISP Proxy Egress Tunnel Routers are described in
      Section 16.

    EID Sub Namespace:  A power-of-two block of aggregatable locators
      set aside for LISP interworking.

4.  Routable EIDs

   An obvious way to achieve interworking between LISP and non-LISP
   hosts is to simply announce EID prefixes into the DFZ, much like
   routing system, effectively treating them as "Provider Independent
   (PI)" prefixes.  Doing this is undesirable as it defeats one of the
   primary goals of LISP - to reduce global routing system state.

4.1.

5.  Impact on Routing Table

   If EID prefixes are announced into the DFZ, the impact is similar to
   the case in which LISP has not been deployed, because these EID
   prefixes will be no more aggregatable than existing PI addressing.
   This behavior is not desirable and such a mechanism is not viewed as
   a viable long term solution.

4.2.

6.  Requirement for using BGP

   Non-LISP sites today use BGP to, among other things, enable ingress
   traffic engineering.  Relaxing this requirement is another primary
   design goal of LISP.

4.3.

7.  Limiting the Impact of Routable EIDs

   Two schemes are proposed to limit the impact of having EIDs announced
   in the current global Internet routing table:

   1.  Section 5 9 discusses the LISP Proxy Tunnel Router, an approach
       that provides ITR functionality to bridge LISP-capable and non-LISP-
      capable non-
       LISP-capable sites.

   2.  Section 6 15 discusses another approach, LISP-NAT, in which NAT
       [RFC2993] is combined with ITR functionality to limit the the
       impact of routable EIDs on the Internet routing infrastructure.

4.4.

8.  Use of Routable EIDs for Testing LISP

   A primary design goal for LISP (and other Locator/ID separation
   proposals) is to facilitate topological aggregation of addresses and,
   thus, decrease global routing system state.  Another goal is to
   achieve the benefits of improved aggregation as soon as possible.
   Advertising
   Sites advertising routes for LISP EID prefixes into the global
   routing system is therefore not recommended.

   That being said, single homed sites (or multi-homed sites that are
   not leaking more specific exceptions) and that are already using
   provider-aggregated prefixes can use these prefixes as LISP EIDs
   without adding state to the routing system; in other words, such
   sites do not cause additional prefixes to be advertised.  For such
   sites, connectivity to a non-LISP sites does not require interworking
   machinery because the "PA" EIDs are already routable.

5. routable (they are
   effectively LISP-R type sites).  Their EIDs are found in the LISP
   mapping system, and their (aggregate) PA prefix(es) are found in the
   DFZ Internet.

   The continued announcements of an existing site's Provider
   Independent (or "PI") prefix(s) is of course under control of that
   site, and some period of transition where a site is is found both in
   the LISP mapping system and as a discrete prefix in the Internet
   routing system may be a viable transition strategy.  Care should be
   taken not to advertise additional more specific LISP EID prefixes
   into the DFZ.

9.  Proxy Ingress Tunnel Routers

   Proxy Ingress Tunnel Routers (PTRs) (PITRs) allow for non-LISP sites to
   communicate with LISP-NR sites.  A PTR PITR is a new network element that
   shares many characteristics with the LISP ITR.  PTRs  PITRs allow non-LISP
   sites to send packets to LISP-NR sites without any changes to
   protocols or equipment at the non-LISP site.  PTRs  PITRs have two primary
   functions:

   Originating EID Advertisements:  PTRs  PITRs advertise highly aggregated
      EID-prefix space on behalf of LISP sites to so that non-LISP sites
      can reach them.

   Encapsulating Legacy Internet Traffic:  PTRs  PITRs also encapsulate non-
      LISP Internet traffic into LISP packets and route them towards
      their destination RLOCs.

5.1.  PTR

10.  PITR EID announcements

   A key part of PTR PITR functionality is to advertise routes for highly-
   aggregated EID prefixes into part of the global routing system.
   Aggressive aggregation is performed to minimize the number of new
   announced routes.  In addition, careful placement of PTRs PITRs can
   greatly reduce the scope of these new routes.  To this end, PTRs PITRs
   should be deployed close to non-LISP-speaking rather than close to
   LISP sites.  Such deployment not only limits the scope of EID-prefix
   route advertisements, it also also allows traffic forwarding load to
   be spread among many PTRs.

5.2. PITRs.

11.  Packet Flow with PTRs PITRs

   Packets from a non-LISP site can reach a LISP-NR site with the aid of
   a PTR. PITR.  By advertising a route for a particular EID prefix into the
   global routing system, traffic destined for that EID prefix is routed
   to the PTR, PITR, which then performs LISP encapsulation.  Once
   encapsulated, traffic packets use the LISP (outer) header's
   destination address to reach the destination ETR.

   What follows is an example of the path a packet would take when using
   a PTR. PITR.  In this example, the LISP-NR site is given the EID prefix
   240.0.0.0/24.  For the purposes of this example, this prefix and no
   covering aggregate is present in the global routing system.  In other
   words, if a packet with this destination were to reach a router in
   the "Default Free Zone", it would be dropped.

   A full protocol exchange example follows:

   1.  Source host makes a DNS lookup EID for destination, and gets
       240.1.1.1 in return.

   2.  Source host has a default route to customer Edge (CE) router and
       forwards the packet to the CE.

   3.  The CE has a default route to its Provider Edge (PE) router, and
       forwards the packet to the PE.

   4.  The PE has route to 240.0.0.0/24 and the next hop is the PTR. PITR.

   5.  The PTR PITR has or acquires a mapping for 240.1.1.1 and LISP
       encapsulates, the packet now has a destination address of the
       RLOC.  The source address of this encapsulated packet is the
       PTR's
       PITR's RLOC.

   6.  The PTR PITR looks up the RLOC, and forwards LISP packet to the next
       hop.

   7.  The ETR decapsulates the packet and delivers the packet to the
       240.1.1.1 host in the destination LISP site.

   8.  Packets from host 240.1.1.1 will flow back through the LISP
       site's ITR.  Such packets are not encapsulated because the ITR
       knows that the destination (the original source) is a non-LISP
       site.  The ITR knows this because it can check the LISP mapping
       database for the destination EID, and on a failure determine that
       the destination site is not LISP enabled.

   9.  Packets are then routed natively and directly to the destination
       (original source) site.

   Note that in this example the return path is asymmetric, so return
   traffic will not go back through the PTR. PITR.  This is because the
   LISP-NR site's ITR will discover that the originating site is not a
   LISP site, and not encapsulate the returning packet (see [LISP] for
   details of ITR behavior).

   The asymmetric nature of traffic flows allows the PTR PITR to be
   relatively simple - it will only have to encapsulate LISP packets.

5.3.

12.  Scaling PTRs

   PTRs PITRs

   PITRs attract traffic by announcing the LISP EID namespace into parts
   of the non-LISP-speaking global routing system.  There are several
   ways that a network could control how traffic reaches a particular
   PTR
   PITR to prevent it from receiving more traffic than it can handle:

   First, the PTR's PITR's aggregate routes might be selectively announced,
   giving a coarse way to control the quantity of traffic attracted by
   that PTR. PITR.

   Second, the same address might be announced by multiple PTRs PITRs in
   order to share the traffic using IP Anycast.  The asymmetric nature
   of traffic flows allows the PTR PITR to be relatively simple - it will
   only have to encapsulate LISP packets.

5.4.

13.  Impact of the PTRs PITRs placement in the network

   There are several approaches that a network could take in placing
   PTRs.
   PITRs.  Placing the PTR PITR near the ingress of traffic allows for the
   communication between the non-LISP site and the LISP site to have the
   least "stretch" (i.e. the least number of forwarding hops when
   compared to an optimal path between the sites).

   Some proposals, for example CRIO [CRIO], have suggested grouping PTRs
   PITRs near an arbitrary subset of ETRs and announcing a 'local'
   subset of EID space.  This model cannot guarantee minimum stretch if
   the EID prefix route advertisement points are changed (such a change
   might occur if a site adds, removes, or replaces one or more ISPs
   connections).

5.5.

14.  Benefit to Networks Deploying PTRs PITRs

   When traffic destined for LISP-NR site arrives and is encapsulated at
   a PTR, PITR, a new LISP packet header is pre-pended.  This causes the
   packet's destination to be set to the destination site RLOC.  Because
   traffic is thus routed towards RLOCs, it can potentially better
   follow the network's traffic engineering policies (such as closest
   exit routing).  This also means that providers who are not default-
   free and do not deploy PTRs PITRs end up sending more traffic to expensive
   transit links rather than to RLOC addresses, to which they may have
   settlement-free peering.  For large transit providers, deploying PTRs
   PITRs may attract more traffic, and therefore more revenue, from
   their customers.

6.

15.  LISP-NAT

   LISP Network Address Translation (LISP-NAT) is a limited form of NAT
   [RFC2993].  LISP-NAT is designed to enable the interworking of non-
   LISP sites and LISP-NR sites by ensuring that the LISP-NR's site
   addresses are always routable.  LISP-NAT accomplishes this by
   translating a host's source address from an 'inner' value to an
   'outer' value and keeping this translation in a table that it can
   reference for subsequent packets.

   In addition, existing RFC 1918 [RFC1918] sites can use LISP-NAT to
   talk to both LISP or non-LISP sites.

   The basic concept of LISP-NAT is that when transmitting a packet, the
   ITR replaces a non-routable EID source address with a routable source
   address, which enables packets to return to the site.

   There are two main cases that involve LISP-NAT:

   1.  Hosts at LISP sites that use non-routable global EIDs speaking to
       non-LISP sites using global addresses.

   2.  Hosts at LISP sites that use RFC 1918 private EIDs speaking to
       other sites, who may be either LISP or non-LISP.

   Note that LISP-NAT is not needed in the case of LISP-R (routable
   global EIDs) sources.  This is because the LISP-R source's address is
   routable, and return packets will be able to natively reach the site.

6.1.

15.1.  LISP-NAT for LISP-NR addressed hosts

   LISP-NAT allows a host with a LISP-NR EID to communicate with non-
   LISP hosts by translating the LISP-NR EID to a globally unique
   address.  This globally unique address may be a either a PI or PA
   address.

   An example of this translation follows.  For this example, a site has
   been assigned a LISP-NR EID of 220.1.1.0/24.  In order to utilize
   LISP-NAT, the site has also been provided the PA EID of
   128.200.1.0/24, and uses the first address (128.200.1.1) as the
   site's RLOC.  The rest of this PA space (128.200.1.2 to
   128.200.1.254) is used as a translation pool for this site's hosts
   who need to communicate with non-LISP hosts.

   The translation table might look like the following:

     Site NR-EID    Site R-EID      Site's RLOC    Translation Pool
   =========================================================================
     ===================================================================
     220.1.1.0/24   128.200.1.0/24  128.200.1.1    128.200.1.2 - 128.200.1.254    128.200.1.2-254

                    Figure 1: Example Translation Table

   The Host 220.1.1.2 sends a packet destined for a non-LISP site to its
   default route (the ITR).  The ITR receives the packet, and determines
   that the destination is not a LISP site.  How the ITR makes this
   determination is up to the ITRs implementation of the EID-to-RLOC
   mapping system used (see, for example [LISP-ALT]).

   The ITR then rewrites the source address of the packet from 220.1.1.2
   to 128.200.1.2, which is the first available address in the LISP-R
   EID space available to it.  The ITR keeps this translation in a table
   in order to reverse this process when receiving packets destined to
   128.200.1.2.

   Finally, when the ITR forwards this packet without encapsulating it,
   it uses the entry in its LISP-NAT table to translate the returning
   packets' destination IPs to the proper host.

6.2.

15.2.  LISP Sites with Hosts using RFC 1918 Addresses Sending to non-LISP non-
       LISP Sites

   In the case where RFC 1918 addressed hosts desire to communicate with
   non-LISP hosts the LISP-NAT implementation acts much like an existing
   IPv4 NAT device.  The ITR providing the NAT service must use LISP-R
   EIDs for its global pool as well as providing all the standard NAT
   functions required today.

   The source of the packet must be translated to a LISP-R EID in a
   manner similar to Section 6, 15, and this packet must be forwarded to
   the ITR's next hop for the destination, without LISP encapsulation.

6.3.

15.3.  LISP Sites with Hosts using RFC 1918 Addresses   Communicating to
       Other LISP Sites

   LISP-NAT allows a host with a RFC 1918 address to communicate with
   LISP hosts by translating the RFC 1918 address to a LISP EID.  After
   translation, the communication between source and destination ITR and
   ETRs continues as described in [LISP].

   An example of this translation and encapsulation follows.  For this
   example, a host has been assigned a RFC 1918 address of 192.168.1.2.
   In order to utilize LISP-NAT, the site also has been provided the
   LISP-R EID of 192.0.2.0/24, and uses the first address (192.0.2.1) as
   the site's RLOC.  The rest of this PA space (192.0.2.2 to
   192.0.2.254) is used as a translation pool for this site's hosts who
   need to communicate with both non-LISP and LISP hosts.

   The Host 192.168.1.2 sends a packet destined for a non-LISP site to
   its default route (the ITR).  The ITR receives the packet and
   determines that the destination is a LISP site.  How the ITR makes
   this determination is up to the ITRs implementation of the EID/RLOC
   mapping system.

   The ITR then rewrites the source address of the packet from
   192.168.1.2 to 192.0.2.2, which is the first available address in the
   LISP EID space available to it.  The ITR keeps this translation in a
   table in order to reverse this process when receiving packets
   destined to 192.0.2.2.

   The ITR then LISP encapsulates this packet (see [LISP] for details).
   The ITR uses the site's RLOC as the LISP outer header's source and
   the translation address as the LISP inner header's source.  Once it
   decapsulates returning traffic, it uses the entry in its LISP-NAT
   table to translate the returning packet's destination IP address and
   then forward to the proper host.

6.4.

15.4.  LISP-NAT and multiple EIDs

   When a site has two addresses that a host might use for global
   reachability, care must be chosen on which EID is found in DNS.  For
   example, whether applications such as DNS use the LISP-R EID or the
   LISP-NR EID.  This problem exists for NAT in general, but the
   specific issue described above is unique to LISP.  Using PTRs PITRs can
   mitigate this problem, since the LISP-NR EID can be reached in all
   cases.

6.5.

15.5.  When LISP-NAT and PTRs Together PITRs used by the same LISP Site

   With LISP-NAT, there are two EIDs possible for a given host, the
   LISP-R EID and the LISP-NR EID.  When a site has two addresses that a
   host might use for global reachability, name-to-address directories
   may need to be modified.

   This problem, global addressability, exists for NAT in general, but
   the specific issue described above is unique to LOC/ID split schemes.
   Some schemes [ref: 6-1 proxy] have suggested running a separate DNS
   instance for legacy types of EIDs.  This solves the problem but
   introduces complexity for the site.  Alternatively, using PTRs PITRs can
   mitigate this problem, because the LISP-NR EID can hbe be reached in all
   cases. all
   cases.

   In summary, there are two options for interworking LISP with IPv4 and
   V6.  In the NAT case the LISP site can use NAT and manage the
   transition on its own.  In the PITR case, we add a new network
   element called a PITR that can relieve that burden on the site, with
   the downside of potentially adding stretch to sites trying to reach
   the LISP site.

16.  Proxy Egress Tunnel Routers

   Proxy Egress Tunnel Routers (PETRs) allow for LISP-NR sites to
   communicate with non-LISP sites in the case where the access network
   does not allow for the LISP-NR site send packets with the source
   address of the site's EID(s).  A PETR is a new network element that
   conceptually acts as an ETR for traffic destined to non-LISP sites.
   This also has the effect of allowing an ITR avoid having to decide
   whether to encapsulate packets or not - it will always encapsulate
   packets.  Packets destined to LISP sites will travel directly to that
   site's ETR, all other packets will be sent to the site's PETR.

   There are two primary reasons why sites would want to utilize a PETR:

   Avoiding strict uRPF failures:  Some provider's access networks
      require the source of the packets emitted to be within the
      addressing scope of the access networks. (see section 9)

   Traversing a different IP Protocol:  A LISP site may want to transmit
      packets to a non-LISP site where the some of the intermediate
      network does not support an IP protocol (v4 or v6).  PETRs can
      allow this LISP site's data to 'hop over' this by utilizing LISP's
      support for mixed protocol encapsulation.

16.1.  Packet Flow with Proxy Egress Tunnel Routers

   Packets from a LISP site can reach a non-LISP site with the aid of a
   Proxy-ETR (or PETR).  An ITR is simply configured to send all non-
   LISP traffic, which it normally would have forwarded natively (non-
   encapsulated), to a PETR.  Note that this outer encapsulation may be
   in another IP protocol than the (inner) encapsulated data.  Traffic
   then uses use the LISP (outer) header's destination address to reach
   the destination PETR.

   A PETR should verify the (inner) source EID of the packet at time of
   decapsulation in order to verify that this is from a configured LISP
   site.  This is to prevent spoofed inner sources from being
   encapsulated through the Proxy-ETR.

   What follows is an example of the path a packet would take when using
   a PETR.  In this example, the LISP-NR site is given the EID prefix
   240.2.0.0/24, and it is trying to reach host at a non-LISP site with
   the IP prefix of 192.0.2.0/24.  For the purposes of this example, the
   destination is a non-LISP site and 192.0.2.0/24 is found in the
   Internet's routing system.

   A full protocol exchange example follows:

   1.  Source host makes a DNS lookup for the destination, and gets
       192.0.2.100 (a non-LISP site) in return.

   2.  Source host has a default route to customer Edge (CE) router and
       forwards the packet towards the CE.

   3.  The CE is a LISP ITR, and is configured to encapsulate traffic
       destined for non-lisp sites to a Proxy-ETR.

   4.  The Proxy ETR decapsulates the LISP packet and forwards the
       original packet to its next hop.

   5.  The packet is then routed natively and directly to the
       destination (non-LISP) site 192.0.2.0/24.

   Note that in this example the return path is asymmetric, so return
   traffic will not go back through the Proxy-ITR.  This means that in
   order to reach LISP-NR sites, non-lisp sites must still use Proxy
   ITRs.

17.  Discussion of Proxy ITRs (PITRs), LISP-NAT, and Proxy-ETRs (PETRs)

   In summary, there are two three options for interworking LISP with non-
   LISP Sites (for both IPv4 and
   V6. IPv6).  In the NAT case LISP-NAT option the LISP
   site can use NAT and manage and control the
   transition interworking on its own.  In the PTR PITR
   case, we add a new network element
   called a PTR that can relieve that burden on the site,
   with the
   downside cost of potentially adding stretch to the connections of
   non-LISP sites trying to reach communicating with the LISP site.

7.  The third option is
   Proxy-ETRs, which are optionally used by sites relying on PITRs case
   to mitigate two caveats for LISP sites communicating with non-LISP
   sites.  This means Proxy-ETRs are not expected to be deployed by
   themselves, they will always be used to assist sites already using
   PITRs.

18.  How Proxy-ITRs and Proxy-ETRs Interact

   There is a subtle difference between Symmetrical (LISP-NAT) vs
   Asymmetrical (Proxy-ITR and Proxy-ETR) Interworking techniques.
   Operationally, Proxy-ITRs (PITRs) and Proxy-ETRs (PETRs) can (and
   likely should) be decoupled since Proxy-ITRs are best deployed
   closest to non-LISP sites, and Proxy-ETRs are best located close to
   the LISP site's they are decapsulating on behalf of.  This asymmetric
   placement of the two network elements keeps the stretched imposed on
   the connection to a minimum, while still allowing for coarsely
   aggregated announcements of EIDs into the Internet's routing table.

19.  Security Considerations

   Like any LISP ITR, PTRs PITRs will have the ability opportunity to inspect traffic
   at the time that they encapsulate.  More work needs to be done to see if
   this ability can be exploited by the control plane along  The location of these devices in
   the lines network can have implications for dropping malicious traffic on
   behalf of
   Remote Triggered BGP Black Holes.  XXX:Reference? ETRs who request this behavior (via the drop action bit in
   Map-Reply packets for an EID or EID prefix).

   As with traditional NAT, LISP-NAT will hide obscure the actual host ID
   LISP-NR EID behind the RLOCs LISP-R addresses used as the NAT pool.

   When LISP Sites reply send packets to non-LISP sites and (these non-LISP rely
   on PTRs PITRs to enable
   Interworking, Interworking), packets will be sourced from addresses have the Site's EID as
   its source IP address.  These EIDs may not be recognized by their
   Internet Service Provider's Unicast Reverse Path Forwarding (uRPF)
   rules enabled on the Provider Edge Router.  Several options are
   available to the service provider.  For example they could enable a
   less strict version of uRPF, where they only look for the existence
   of the the EID prefix in the routing table.  Another, more secure,
   option is to add a static route for the customer on the PE router,
   but not redistribute this route into the provider's routing table.

8.
   Finally, Proxy-ETRs can enable LISP sites to bypass this uRPF check
   by encapsulating all of their egressing traffic destined to non-LISP
   sites to the Proxy-ETR (thus ensuring the outer IP source address is
   the site's RLOC).

20.  Acknowledgments

   Thanks goes to Christian Vogt, Lixia Zhang and Zhang, Robin Whittle Whittle, Michael
   Menth, and Xuewei Wang who have made insightful comments with respect
   to interworking LISP Interworking and transition mechanisms.

   A special thanks goes to Scott Brim for his initial brainstorming of
   these ideas and also for his careful review.

9.

21.  IANA Considerations

   This document creates no new requirements on IANA namespaces
   [RFC2434].

10.

22.  References

10.1.

22.1.  Normative References

   [LISP]     Farinacci, D., Fuller, V., Oran, Meyer, D., and D. Meyer, Lewis,
              "Locator/ID Separation Protocol (LISP)",
              draft-ietf-lisp-00
              draft-ietf-lisp-06 (work in progress), May 2009. January 2010.

   [LISP-ALT]
              Farinacci, D., Fuller, V., Meyer, D., and D. Meyer, Lewis, "LISP
              Alternative Topology (LISP-ALT)", draft-ietf-lisp-alt-00
              draft-ietf-lisp-alt-02.txt (work in progress), May 2009.
              January 2010.

   [RFC1918]  Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
              E. Lear, "Address Allocation for Private Internets",
              BCP 5, RFC 1918, February 1996.

   [RFC4632]  Fuller, V. and T. Li, "Classless Inter-domain Routing
              (CIDR): The Internet Address Assignment and Aggregation
              Plan", BCP 122, RFC 4632, August 2006.

10.2.

22.2.  Informative References

   [CRIO]     Zhang, X., Francis, P., Wang, J., and K. Yoshida, "CRIO:
              Scaling IP Routing with the Core Router-Integrated
              Overlay".

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 2434,
              October 1998.

   [RFC2993]  Hain, T., "Architectural Implications of NAT", RFC 2993,
              November 2000.

Authors' Addresses

   Darrel Lewis
   Cisco Systems, Inc.

   Email: darlewis@cisco.com

   David Meyer
   Cisco Systems, Inc.

   Email: dmm@cisco.com

   Dino Farinacci
   Cisco Systems, Inc.

   Email: dino@cisco.com

   Vince Fuller
   Cisco Systems, Inc.

   Email: vaf@cisco.com
--Apple-Mail-6--53398945 Content-Disposition: attachment; filename=draft-ietf-lisp-interworking-01.txt Content-Type: text/plain; name="draft-ietf-lisp-interworking-01.txt" Content-Transfer-Encoding: quoted-printable Network Working Group D. Lewis Internet-Draft D. Meyer Intended status: Experimental D. Farinacci Expires: August 16, 2010 V. Fuller Cisco Systems, Inc. February 12, 2010 Interworking LISP with IPv4 and IPv6 draft-ietf-lisp-interworking-01.txt Abstract This document describes techniques for allowing sites running the Locator/ID Separation Protocol (LISP [LISP]) to interoperate with Internet sites (using either IPv4, IPv6, or both) which are not running LISP. A fundamental property of LISP speaking sites is that they use Endpoint Identifiers (EIDs), rather than traditional IP addresses, in the source and destination fields of all traffic they emit or receive. While EIDs are syntactically identical to IPv4 or IPv6 addresses, routes for them are not carried in the global routing system so an interoperability mechanism is needed for non-LISP- speaking sites to exchange traffic with LISP-speaking sites. This document introduces three such mechanisms: the first uses a new network element, the LISP Proxy Ingress Tunnel Routers (PITR) (Section 5) to act as a intermediate LISP Ingress Tunnel Router (ITR) for non-LISP-speaking hosts while the second adds Network Address Translation (NAT) functionality to LISP Ingress and LISP Egress Tunnel Routers (xTRs) to substitute routable IP addresses for non- routable EIDs. Finally, this document introduces a Proxy Egress Tunnel Router (PETR) to solve cases where a LISP site cannot send a packet which has as its source address a non-routable EID Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." Lewis, et al. Expires August 16, 2010 [Page 1] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 16, 2010. Copyright Notice Copyright (c) 2010 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 BSD License. Lewis, et al. Expires August 16, 2010 [Page 2] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. LISP Interworking Models . . . . . . . . . . . . . . . . . . . 6 3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 8 4. Routable EIDs . . . . . . . . . . . . . . . . . . . . . . . . 11 5. Impact on Routing Table . . . . . . . . . . . . . . . . . . . 12 6. Requirement for using BGP . . . . . . . . . . . . . . . . . . 13 7. Limiting the Impact of Routable EIDs . . . . . . . . . . . . . 14 8. Use of Routable EIDs for Testing LISP . . . . . . . . . . . . 15 9. Proxy Ingress Tunnel Routers . . . . . . . . . . . . . . . . . 16 10. PITR EID announcements . . . . . . . . . . . . . . . . . . . . 17 11. Packet Flow with PITRs . . . . . . . . . . . . . . . . . . . . 18 12. Scaling PITRs . . . . . . . . . . . . . . . . . . . . . . . . 20 13. Impact of the PITRs placement in the network . . . . . . . . . 21 14. Benefit to Networks Deploying PITRs . . . . . . . . . . . . . 22 15. LISP-NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 15.1. LISP-NAT for LISP-NR addressed hosts . . . . . . . . . . 23 15.2. LISP Sites with Hosts using RFC 1918 Addresses Sending to non-LISP Sites . . . . . . . . . . . . . . . . 24 15.3. LISP Sites with Hosts using RFC 1918 Addresses Communicating to Other LISP Sites . . . . . . . . . . . . 24 15.4. LISP-NAT and multiple EIDs . . . . . . . . . . . . . . . 25 15.5. When LISP-NAT and PITRs used by the same LISP Site . . . 25 16. Proxy Egress Tunnel Routers . . . . . . . . . . . . . . . . . 27 16.1. Packet Flow with Proxy Egress Tunnel Routers . . . . . . 27 17. Discussion of Proxy ITRs (PITRs), LISP-NAT, and Proxy-ETRs (PETRs) . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 18. How Proxy-ITRs and Proxy-ETRs Interact . . . . . . . . . . . . 30 19. Security Considerations . . . . . . . . . . . . . . . . . . . 31 20. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 32 21. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 22. References . . . . . . . . . . . . . . . . . . . . . . . . . . 34 22.1. Normative References . . . . . . . . . . . . . . . . . . 34 22.2. Informative References . . . . . . . . . . . . . . . . . 34 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 35 Lewis, et al. Expires August 16, 2010 [Page 3] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 1. Introduction This document describes two mechanisms for interoperation between LISP [LISP] sites, which use non-globally-routed EIDs, and non-LISP sites: use of PITRs, which create highly-aggregated routes to EID prefixes for non-LISP sites to follow. The use of NAT by LISP ETRs when communicating with non-LISP hosts. And finally the use of Proxy Egress Tunnel routers (PETRs) LISP for sites relying on PITRs and which are faced with certain restrictions. A key behavior of the separation of Locators and End-Point-IDs is that EID prefixes are not advertised to the Internet's Default Free Zone (DFZ). Specifically, only RLOCs are carried in the Internet's DFZ. Existing Internet sites (and their hosts) who do not participate in the LISP system must still be able to reach sites numbered from this non routed EID space. This draft describes a set of mechanisms that can be used to provide reachability between sites that are LISP-capable and those that are not. This document introduces three such mechanisms. The first uses a new network element, the LISP Proxy Ingress Tunnel Router (PITR) (Section 5) to act as a intermediate LISP Ingress Tunnel Router (ITR) for non-LISP- speaking hosts. The second adds a form of Network Address Translation (NAT) functionality to Tunnel Routers (xTRs) to substitute routable IP addresses for non-routable EIDs. The final network element is the LISP Proxy Egress Tunnel Routers (PETR), which act as an intermediate Egress Tunnel Router (ETR) for LISP sites who are using PITRs but need assistance in reaching non-LISP sites. More detailed descriptions of these mechanisms and the network elements involved may be found in the following sections: - Section 2 describes the different cases where interworking mechanisms are needed - Section 3 defines terms used throughout the document - Section 4 describes the relationship between the new EID prefix space and the IP address space used by the current Internet - Section 5 introduces and describes the operation of Proxy-ITRs - Section 6 defines how NAT is used by ETRs to translate non-routable EIDs into routable IP addresses. - Section 7 introduces and describes the operations of Proxy-ETRs - Section 8 describes the relationship between asymmetric and Symmetric interworking mechanisms (Proxy-ITRs and Proxy-ETRs vs LISP- Lewis, et al. Expires August 16, 2010 [Page 4] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 NAT) Note that any successful interworking model should be independent of any particular EID-to-RLOC mapping algorithm. This document does not comment on the value of any of the particular LISP mapping systems. Lewis, et al. Expires August 16, 2010 [Page 5] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 2. LISP Interworking Models There are 4 unicast connectivity cases which describe how sites can communicate with each other: 1. Non-LISP site to Non-LISP site 2. LISP site to LISP site 3. LISP site to Non-LISP site 4. Non-LISP site to LISP site Note that while Cases 3 and 4 seem similar, there are subtle differences due to the way communications are originated. The first case is the Internet as we know it today and as such will not be discussed further here. The second case is documented in [LISP] and, hence, there are no new interworking requirements because there are no new protocol requirements placed on intermediate non- LISP routers. In case 3, LISP site to Non-LISP site, a LISP site can (in most cases) send packets to a non-LISP site because the non-LISP site prefixes are routable. The non-LISP site need not do anything new to receive packets. The only action the LISP site needs (with two possible caveats introduced below) to take is to know when not to LISP-encapsulate packets. This can be achieved via two mechanisms: 1. At the ITR in the source site, if the destination of an IP packet is found to match a prefix from the BGP routing table, then the site is directly reachable by the BGP core that exists and operates today. 2. Second, if (from the perspective of the ITR at the source site) the destination address of an IP address is not found in the EID- to-RLOC mapping database, the ITR could infer that it is not a LISP-capable site, and decide to not LISP-encapsulate the packet. 3. There are two potential caveats involved with Case 3, where there could be some situations where (unencapsualted) packets originated by a LISP site may not be forwarded to a non-LISP site. One of these caveats (uRPF check failure) are detailed in Section 9 (Security Considerations). The second caveat (protocol traversal) is reviewed in section 7, (Proxy-Egress Tunnel Routers). Case 4, typically the most challenging, occurs when a host at a non- Lewis, et al. Expires August 16, 2010 [Page 6] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 LISP site wishes to send traffic to a host at a LISP site. If the source host uses a (non-globally-routable) EID as the destination IP address, the packet is forwarded inside the source site until it reaches a router which cannot forward it, at which point the traffic is dropped. For traffic not to be dropped, either some route must be exist for the destination EID outside of LISP-speaking part of the network or an alternate mechanism must be in place. Section 5 (PITRs) and Section 6 (LISP-NAT) describe two such mechanisms. Note that case 4 includes packets returning to the LISP Site in case 3. Lewis, et al. Expires August 16, 2010 [Page 7] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 3. Definition of Terms Endpoint ID (EID): Endpoint ID (EID): A 32-bit (for IPv4) or 128-bit (for IPv6) value used in the source and destination address fields of the first (most inner) LISP header of a packet. The host obtains a destination EID the same way it obtains an destination address today, for example through a DNS lookup or SIP exchange. The source EID is obtained via existing mechanisms used to set a host's "local" IP address. An EID is allocated to a host from an EID-prefix block associated with the site where the host is located. An EID can be used by a host to refer to other hosts. EIDs MUST NOT be used as LISP RLOCs. Note that EID blocks may be assigned in a hierarchical manner, independent of the network topology, to facilitate scaling of the mapping database. In addition, an EID block assigned to a site may have site-local structure (subnetting) for routing within the site; this structure is not visible to the global routing system. When used in discussions with other Locator/ID separation proposals, a LISP EID will be called a "LEID". Throughout this document, any references to "EID" refers to an LEID. EID-Prefix: EID-prefix: A power-of-2 block of EIDs which are allocated to a site by an address allocation authority. EID- prefixes are associated with a set of RLOC addresses which make up a "database mapping". EID-prefix allocations can be broken up into smaller blocks when an RLOC set is to be associated with the smaller EID- prefix. A globally routed address block (whether PI or PA) is not an EID-prefix. However, a globally routed address block may be removed from global routing and reused as an EID- prefix. A site that receives an explicitly allocated EID-prefix may not use that EID-prefix as a globally routed prefix assigned to RLOCs EID-Prefix Aggregate: A set of EID-prefixes said to be aggregatable in the [RFC4632] sense. That is, an EID-Prefix aggregate is defined to be a single contiguous power-of-two EID-prefix block. Such a block is characterized by a prefix and a length. Provider Independent (PI) Addresses: an address block assigned from a pool where blocks are not associated with any particular location in the network (e.g. from a particular service provider), and is therefore not topologically aggregatable in the routing system. Routing Locator (RLOC): The IPv4 or IPv6 address of an egress tunnel router (ETR). It is the output of a EID-to-RLOC mapping lookup. An EID maps to one or more RLOCs. Typically, RLOCs are numbered from topologically-aggregatable blocks that are assigned to a site at each point to which it attaches to the global Internet; where the topology is defined by the connectivity of provider networks, Lewis, et al. Expires August 16, 2010 [Page 8] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 RLOCs can be thought of as PA addresses. Multiple RLOCs can be assigned to the same ETR device or to multiple ETR devices at a site. EID-to-RLOC Mapping: A binding between an EID and the RLOC-set that can be used to reach the EID. We use the term "mapping" in this document to refer to a EID-to-RLOC mapping. EID Prefix Reachability: An EID prefix is said to be "reachable" if one or more of its locators are reachable. That is, an EID prefix is reachable if the ETR (or its proxy) is reachable. Default Mapping: A Default Mapping is a mapping entry for EID-prefix 0.0.0.0/0. It maps to a locator-set used for all EIDs in the Internet. If there is a more specific EID-prefix in the mapping cache it overrides the Default Mapping entry. The Default Mapping route can be learned by configuration or from a Map-Reply message [LISP]. LISP Routable (LISP-R) Site: A LISP site whose addresses are used as both globally routable IP addresses and LISP EIDs. LISP Non-Routable (LISP-NR) Site: A LISP site whose addresses are EIDs only, these EIDs are not found in the legacy Internet routing table. LISP Proxy Ingress Tunnel Router (PITR): PITRs are used to provide interconnectivity between sites which use LISP EIDs and those which do not. They act as a gateway between the Legacy Internet and the LISP enabled Network. A given PITR advertises one or more highly aggregated EID prefixes into the public Internet and acts as the ITR for traffic received from the public Internet. LISP Proxy Ingress Tunnel Routers are described in Section 9. LISP Network Address Translation (LISP-NAT): Network Address Translation between EID space assigned to a site and RLOC space also assigned to that site. LISP Network Address Translation is described in Section 15. LISP Proxy Egress Tunnel Router (PETR): PETRs are used to provide a LISP site's ITRs the ability to send traffic to non-LISP sites in cases where unencapsualted packets (the default mechanism) would fail to be delivered. PETRs are implemented by having an ITR encapsulate all non-LISP destined traffic to a pre-configured PETR. LISP Proxy Egress Tunnel Routers are described in Section 16. Lewis, et al. Expires August 16, 2010 [Page 9] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 EID Sub Namespace: A power-of-two block of aggregatable locators set aside for LISP interworking. Lewis, et al. Expires August 16, 2010 [Page 10] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 4. Routable EIDs An obvious way to achieve interworking between LISP and non-LISP hosts is to simply announce EID prefixes into the DFZ, much like routing system, effectively treating them as "Provider Independent (PI)" prefixes. Doing this is undesirable as it defeats one of the primary goals of LISP - to reduce global routing system state. Lewis, et al. Expires August 16, 2010 [Page 11] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 5. Impact on Routing Table If EID prefixes are announced into the DFZ, the impact is similar to the case in which LISP has not been deployed, because these EID prefixes will be no more aggregatable than existing PI addressing. This behavior is not desirable and such a mechanism is not viewed as a viable long term solution. Lewis, et al. Expires August 16, 2010 [Page 12] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 6. Requirement for using BGP Non-LISP sites today use BGP to, among other things, enable ingress traffic engineering. Relaxing this requirement is another primary design goal of LISP. Lewis, et al. Expires August 16, 2010 [Page 13] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 7. Limiting the Impact of Routable EIDs Two schemes are proposed to limit the impact of having EIDs announced in the current global Internet routing table: 1. Section 9 discusses the LISP Proxy Tunnel Router, an approach that provides ITR functionality to bridge LISP-capable and non- LISP-capable sites. 2. Section 15 discusses another approach, LISP-NAT, in which NAT [RFC2993] is combined with ITR functionality to limit the the impact of routable EIDs on the Internet routing infrastructure. Lewis, et al. Expires August 16, 2010 [Page 14] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 8. Use of Routable EIDs for Testing LISP A primary design goal for LISP (and other Locator/ID separation proposals) is to facilitate topological aggregation of addresses and, thus, decrease global routing system state. Another goal is to achieve the benefits of improved aggregation as soon as possible. Sites advertising routes for LISP EID prefixes into the global routing system is therefore not recommended. That being said, single homed sites (or multi-homed sites that are not leaking more specific exceptions) and that are already using provider-aggregated prefixes can use these prefixes as LISP EIDs without adding state to the routing system; in other words, such sites do not cause additional prefixes to be advertised. For such sites, connectivity to a non-LISP sites does not require interworking machinery because the "PA" EIDs are already routable (they are effectively LISP-R type sites). Their EIDs are found in the LISP mapping system, and their (aggregate) PA prefix(es) are found in the DFZ Internet. The continued announcements of an existing site's Provider Independent (or "PI") prefix(s) is of course under control of that site, and some period of transition where a site is is found both in the LISP mapping system and as a discrete prefix in the Internet routing system may be a viable transition strategy. Care should be taken not to advertise additional more specific LISP EID prefixes into the DFZ. Lewis, et al. Expires August 16, 2010 [Page 15] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 9. Proxy Ingress Tunnel Routers Proxy Ingress Tunnel Routers (PITRs) allow for non-LISP sites to communicate with LISP-NR sites. A PITR is a new network element that shares many characteristics with the LISP ITR. PITRs allow non-LISP sites to send packets to LISP-NR sites without any changes to protocols or equipment at the non-LISP site. PITRs have two primary functions: Originating EID Advertisements: PITRs advertise highly aggregated EID-prefix space on behalf of LISP sites to so that non-LISP sites can reach them. Encapsulating Legacy Internet Traffic: PITRs also encapsulate non- LISP Internet traffic into LISP packets and route them towards their destination RLOCs. Lewis, et al. Expires August 16, 2010 [Page 16] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 10. PITR EID announcements A key part of PITR functionality is to advertise routes for highly- aggregated EID prefixes into part of the global routing system. Aggressive aggregation is performed to minimize the number of new announced routes. In addition, careful placement of PITRs can greatly reduce the scope of these new routes. To this end, PITRs should be deployed close to non-LISP-speaking rather than close to LISP sites. Such deployment not only limits the scope of EID-prefix route advertisements, it also also allows traffic forwarding load to be spread among many PITRs. Lewis, et al. Expires August 16, 2010 [Page 17] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 11. Packet Flow with PITRs Packets from a non-LISP site can reach a LISP-NR site with the aid of a PITR. By advertising a route for a particular EID prefix into the global routing system, traffic destined for that EID prefix is routed to the PITR, which then performs LISP encapsulation. Once encapsulated, traffic packets use the LISP (outer) header's destination address to reach the destination ETR. What follows is an example of the path a packet would take when using a PITR. In this example, the LISP-NR site is given the EID prefix 240.0.0.0/24. For the purposes of this example, this prefix and no covering aggregate is present in the global routing system. In other words, if a packet with this destination were to reach a router in the "Default Free Zone", it would be dropped. A full protocol exchange example follows: 1. Source host makes a DNS lookup EID for destination, and gets 240.1.1.1 in return. 2. Source host has a default route to customer Edge (CE) router and forwards the packet to the CE. 3. The CE has a default route to its Provider Edge (PE) router, and forwards the packet to the PE. 4. The PE has route to 240.0.0.0/24 and the next hop is the PITR. 5. The PITR has or acquires a mapping for 240.1.1.1 and LISP encapsulates, the packet now has a destination address of the RLOC. The source address of this encapsulated packet is the PITR's RLOC. 6. The PITR looks up the RLOC, and forwards LISP packet to the next hop. 7. The ETR decapsulates the packet and delivers the packet to the 240.1.1.1 host in the destination LISP site. 8. Packets from host 240.1.1.1 will flow back through the LISP site's ITR. Such packets are not encapsulated because the ITR knows that the destination (the original source) is a non-LISP site. The ITR knows this because it can check the LISP mapping database for the destination EID, and on a failure determine that the destination site is not LISP enabled. Lewis, et al. Expires August 16, 2010 [Page 18] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 9. Packets are then routed natively and directly to the destination (original source) site. Note that in this example the return path is asymmetric, so return traffic will not go back through the PITR. This is because the LISP-NR site's ITR will discover that the originating site is not a LISP site, and not encapsulate the returning packet (see [LISP] for details of ITR behavior). The asymmetric nature of traffic flows allows the PITR to be relatively simple - it will only have to encapsulate LISP packets. Lewis, et al. Expires August 16, 2010 [Page 19] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 12. Scaling PITRs PITRs attract traffic by announcing the LISP EID namespace into parts of the non-LISP-speaking global routing system. There are several ways that a network could control how traffic reaches a particular PITR to prevent it from receiving more traffic than it can handle: First, the PITR's aggregate routes might be selectively announced, giving a coarse way to control the quantity of traffic attracted by that PITR. Second, the same address might be announced by multiple PITRs in order to share the traffic using IP Anycast. The asymmetric nature of traffic flows allows the PITR to be relatively simple - it will only have to encapsulate LISP packets. Lewis, et al. Expires August 16, 2010 [Page 20] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 13. Impact of the PITRs placement in the network There are several approaches that a network could take in placing PITRs. Placing the PITR near the ingress of traffic allows for the communication between the non-LISP site and the LISP site to have the least "stretch" (i.e. the least number of forwarding hops when compared to an optimal path between the sites). Some proposals, for example CRIO [CRIO], have suggested grouping PITRs near an arbitrary subset of ETRs and announcing a 'local' subset of EID space. This model cannot guarantee minimum stretch if the EID prefix route advertisement points are changed (such a change might occur if a site adds, removes, or replaces one or more ISPs connections). Lewis, et al. Expires August 16, 2010 [Page 21] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 14. Benefit to Networks Deploying PITRs When traffic destined for LISP-NR site arrives and is encapsulated at a PITR, a new LISP packet header is pre-pended. This causes the packet's destination to be set to the destination site RLOC. Because traffic is thus routed towards RLOCs, it can potentially better follow the network's traffic engineering policies (such as closest exit routing). This also means that providers who are not default- free and do not deploy PITRs end up sending more traffic to expensive transit links rather than to RLOC addresses, to which they may have settlement-free peering. For large transit providers, deploying PITRs may attract more traffic, and therefore more revenue, from their customers. Lewis, et al. Expires August 16, 2010 [Page 22] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 15. LISP-NAT LISP Network Address Translation (LISP-NAT) is a limited form of NAT [RFC2993]. LISP-NAT is designed to enable the interworking of non- LISP sites and LISP-NR sites by ensuring that the LISP-NR's site addresses are always routable. LISP-NAT accomplishes this by translating a host's source address from an 'inner' value to an 'outer' value and keeping this translation in a table that it can reference for subsequent packets. In addition, existing RFC 1918 [RFC1918] sites can use LISP-NAT to talk to both LISP or non-LISP sites. The basic concept of LISP-NAT is that when transmitting a packet, the ITR replaces a non-routable EID source address with a routable source address, which enables packets to return to the site. There are two main cases that involve LISP-NAT: 1. Hosts at LISP sites that use non-routable global EIDs speaking to non-LISP sites using global addresses. 2. Hosts at LISP sites that use RFC 1918 private EIDs speaking to other sites, who may be either LISP or non-LISP. Note that LISP-NAT is not needed in the case of LISP-R (routable global EIDs) sources. This is because the LISP-R source's address is routable, and return packets will be able to natively reach the site. 15.1. LISP-NAT for LISP-NR addressed hosts LISP-NAT allows a host with a LISP-NR EID to communicate with non- LISP hosts by translating the LISP-NR EID to a globally unique address. This globally unique address may be a either a PI or PA address. An example of this translation follows. For this example, a site has been assigned a LISP-NR EID of 220.1.1.0/24. In order to utilize LISP-NAT, the site has also been provided the PA EID of 128.200.1.0/24, and uses the first address (128.200.1.1) as the site's RLOC. The rest of this PA space (128.200.1.2 to 128.200.1.254) is used as a translation pool for this site's hosts who need to communicate with non-LISP hosts. The translation table might look like the following: Lewis, et al. Expires August 16, 2010 [Page 23] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 Site NR-EID Site R-EID Site's RLOC Translation Pool =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 220.1.1.0/24 128.200.1.0/24 128.200.1.1 128.200.1.2-254 Figure 1: Example Translation Table The Host 220.1.1.2 sends a packet destined for a non-LISP site to its default route (the ITR). The ITR receives the packet, and determines that the destination is not a LISP site. How the ITR makes this determination is up to the ITRs implementation of the EID-to-RLOC mapping system used (see, for example [LISP-ALT]). The ITR then rewrites the source address of the packet from 220.1.1.2 to 128.200.1.2, which is the first available address in the LISP-R EID space available to it. The ITR keeps this translation in a table in order to reverse this process when receiving packets destined to 128.200.1.2. Finally, when the ITR forwards this packet without encapsulating it, it uses the entry in its LISP-NAT table to translate the returning packets' destination IPs to the proper host. 15.2. LISP Sites with Hosts using RFC 1918 Addresses Sending to non- LISP Sites In the case where RFC 1918 addressed hosts desire to communicate with non-LISP hosts the LISP-NAT implementation acts much like an existing IPv4 NAT device. The ITR providing the NAT service must use LISP-R EIDs for its global pool as well as providing all the standard NAT functions required today. The source of the packet must be translated to a LISP-R EID in a manner similar to Section 15, and this packet must be forwarded to the ITR's next hop for the destination, without LISP encapsulation. 15.3. LISP Sites with Hosts using RFC 1918 Addresses Communicating to Other LISP Sites LISP-NAT allows a host with a RFC 1918 address to communicate with LISP hosts by translating the RFC 1918 address to a LISP EID. After translation, the communication between source and destination ITR and ETRs continues as described in [LISP]. An example of this translation and encapsulation follows. For this example, a host has been assigned a RFC 1918 address of 192.168.1.2. In order to utilize LISP-NAT, the site also has been provided the LISP-R EID of 192.0.2.0/24, and uses the first address (192.0.2.1) as the site's RLOC. The rest of this PA space (192.0.2.2 to Lewis, et al. Expires August 16, 2010 [Page 24] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 192.0.2.254) is used as a translation pool for this site's hosts who need to communicate with both non-LISP and LISP hosts. The Host 192.168.1.2 sends a packet destined for a non-LISP site to its default route (the ITR). The ITR receives the packet and determines that the destination is a LISP site. How the ITR makes this determination is up to the ITRs implementation of the EID/RLOC mapping system. The ITR then rewrites the source address of the packet from 192.168.1.2 to 192.0.2.2, which is the first available address in the LISP EID space available to it. The ITR keeps this translation in a table in order to reverse this process when receiving packets destined to 192.0.2.2. The ITR then LISP encapsulates this packet (see [LISP] for details). The ITR uses the site's RLOC as the LISP outer header's source and the translation address as the LISP inner header's source. Once it decapsulates returning traffic, it uses the entry in its LISP-NAT table to translate the returning packet's destination IP address and then forward to the proper host. 15.4. LISP-NAT and multiple EIDs When a site has two addresses that a host might use for global reachability, care must be chosen on which EID is found in DNS. For example, whether applications such as DNS use the LISP-R EID or the LISP-NR EID. This problem exists for NAT in general, but the specific issue described above is unique to LISP. Using PITRs can mitigate this problem, since the LISP-NR EID can be reached in all cases. 15.5. When LISP-NAT and PITRs used by the same LISP Site With LISP-NAT, there are two EIDs possible for a given host, the LISP-R EID and the LISP-NR EID. When a site has two addresses that a host might use for global reachability, name-to-address directories may need to be modified. This problem, global addressability, exists for NAT in general, but the specific issue described above is unique to LOC/ID split schemes. Some schemes [ref: 6-1 proxy] have suggested running a separate DNS instance for legacy types of EIDs. This solves the problem but introduces complexity for the site. Alternatively, using PITRs can mitigate this problem, because the LISP-NR EID can be reached in all cases. In summary, there are two options for interworking LISP with IPv4 and Lewis, et al. Expires August 16, 2010 [Page 25] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 V6. In the NAT case the LISP site can use NAT and manage the transition on its own. In the PITR case, we add a new network element called a PITR that can relieve that burden on the site, with the downside of potentially adding stretch to sites trying to reach the LISP site. Lewis, et al. Expires August 16, 2010 [Page 26] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 16. Proxy Egress Tunnel Routers Proxy Egress Tunnel Routers (PETRs) allow for LISP-NR sites to communicate with non-LISP sites in the case where the access network does not allow for the LISP-NR site send packets with the source address of the site's EID(s). A PETR is a new network element that conceptually acts as an ETR for traffic destined to non-LISP sites. This also has the effect of allowing an ITR avoid having to decide whether to encapsulate packets or not - it will always encapsulate packets. Packets destined to LISP sites will travel directly to that site's ETR, all other packets will be sent to the site's PETR. There are two primary reasons why sites would want to utilize a PETR: Avoiding strict uRPF failures: Some provider's access networks require the source of the packets emitted to be within the addressing scope of the access networks. (see section 9) Traversing a different IP Protocol: A LISP site may want to transmit packets to a non-LISP site where the some of the intermediate network does not support an IP protocol (v4 or v6). PETRs can allow this LISP site's data to 'hop over' this by utilizing LISP's support for mixed protocol encapsulation. 16.1. Packet Flow with Proxy Egress Tunnel Routers Packets from a LISP site can reach a non-LISP site with the aid of a Proxy-ETR (or PETR). An ITR is simply configured to send all non- LISP traffic, which it normally would have forwarded natively (non- encapsulated), to a PETR. Note that this outer encapsulation may be in another IP protocol than the (inner) encapsulated data. Traffic then uses use the LISP (outer) header's destination address to reach the destination PETR. A PETR should verify the (inner) source EID of the packet at time of decapsulation in order to verify that this is from a configured LISP site. This is to prevent spoofed inner sources from being encapsulated through the Proxy-ETR. What follows is an example of the path a packet would take when using a PETR. In this example, the LISP-NR site is given the EID prefix 240.2.0.0/24, and it is trying to reach host at a non-LISP site with the IP prefix of 192.0.2.0/24. For the purposes of this example, the destination is a non-LISP site and 192.0.2.0/24 is found in the Internet's routing system. A full protocol exchange example follows: Lewis, et al. Expires August 16, 2010 [Page 27] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 1. Source host makes a DNS lookup for the destination, and gets 192.0.2.100 (a non-LISP site) in return. 2. Source host has a default route to customer Edge (CE) router and forwards the packet towards the CE. 3. The CE is a LISP ITR, and is configured to encapsulate traffic destined for non-lisp sites to a Proxy-ETR. 4. The Proxy ETR decapsulates the LISP packet and forwards the original packet to its next hop. 5. The packet is then routed natively and directly to the destination (non-LISP) site 192.0.2.0/24. Note that in this example the return path is asymmetric, so return traffic will not go back through the Proxy-ITR. This means that in order to reach LISP-NR sites, non-lisp sites must still use Proxy ITRs. Lewis, et al. Expires August 16, 2010 [Page 28] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 17. Discussion of Proxy ITRs (PITRs), LISP-NAT, and Proxy-ETRs (PETRs) In summary, there are three options for interworking LISP with non- LISP Sites (for both IPv4 and IPv6). In the LISP-NAT option the LISP site can manage and control the interworking on its own. In the PITR case, we add a new network element relieve that burden on the site, with the cost of potentially adding stretch to the connections of non-LISP sites communicating with the LISP site. The third option is Proxy-ETRs, which are optionally used by sites relying on PITRs case to mitigate two caveats for LISP sites communicating with non-LISP sites. This means Proxy-ETRs are not expected to be deployed by themselves, they will always be used to assist sites already using PITRs. Lewis, et al. Expires August 16, 2010 [Page 29] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 18. How Proxy-ITRs and Proxy-ETRs Interact There is a subtle difference between Symmetrical (LISP-NAT) vs Asymmetrical (Proxy-ITR and Proxy-ETR) Interworking techniques. Operationally, Proxy-ITRs (PITRs) and Proxy-ETRs (PETRs) can (and likely should) be decoupled since Proxy-ITRs are best deployed closest to non-LISP sites, and Proxy-ETRs are best located close to the LISP site's they are decapsulating on behalf of. This asymmetric placement of the two network elements keeps the stretched imposed on the connection to a minimum, while still allowing for coarsely aggregated announcements of EIDs into the Internet's routing table. Lewis, et al. Expires August 16, 2010 [Page 30] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 19. Security Considerations Like any LISP ITR, PITRs will have the opportunity to inspect traffic at the time that they encapsulate. The location of these devices in the network can have implications for dropping malicious traffic on behalf of ETRs who request this behavior (via the drop action bit in Map-Reply packets for an EID or EID prefix). As with traditional NAT, LISP-NAT will obscure the actual host LISP-NR EID behind the LISP-R addresses used as the NAT pool. When LISP Sites send packets to non-LISP sites (these non-LISP rely on PITRs to enable Interworking), packets will have the Site's EID as its source IP address. These EIDs may not be recognized by their Internet Service Provider's Unicast Reverse Path Forwarding (uRPF) rules enabled on the Provider Edge Router. Several options are available to the service provider. For example they could enable a less strict version of uRPF, where they only look for the existence of the the EID prefix in the routing table. Another, more secure, option is to add a static route for the customer on the PE router, but not redistribute this route into the provider's routing table. Finally, Proxy-ETRs can enable LISP sites to bypass this uRPF check by encapsulating all of their egressing traffic destined to non-LISP sites to the Proxy-ETR (thus ensuring the outer IP source address is the site's RLOC). Lewis, et al. Expires August 16, 2010 [Page 31] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 20. Acknowledgments Thanks goes to Christian Vogt, Lixia Zhang, Robin Whittle, Michael Menth, and Xuewei Wang who have made insightful comments with respect to LISP Interworking and transition mechanisms. A special thanks goes to Scott Brim for his initial brainstorming of these ideas and also for his careful review. Lewis, et al. Expires August 16, 2010 [Page 32] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 21. IANA Considerations This document creates no new requirements on IANA namespaces [RFC2434]. Lewis, et al. Expires August 16, 2010 [Page 33] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 22. References 22.1. Normative References [LISP] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "Locator/ID Separation Protocol (LISP)", draft-ietf-lisp-06 (work in progress), January 2010. [LISP-ALT] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "LISP Alternative Topology (LISP-ALT)", draft-ietf-lisp-alt-02.txt (work in progress), January 2010. [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, February 1996. [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan", BCP 122, RFC 4632, August 2006. 22.2. Informative References [CRIO] Zhang, X., Francis, P., Wang, J., and K. Yoshida, "CRIO: Scaling IP Routing with the Core Router-Integrated Overlay". [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [RFC2993] Hain, T., "Architectural Implications of NAT", RFC 2993, November 2000. Lewis, et al. Expires August 16, 2010 [Page 34] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 Authors' Addresses Darrel Lewis Cisco Systems, Inc. Email: darlewis@cisco.com David Meyer Cisco Systems, Inc. Email: dmm@cisco.com Dino Farinacci Cisco Systems, Inc. Email: dino@cisco.com Vince Fuller Cisco Systems, Inc. Email: vaf@cisco.com Lewis, et al. Expires August 16, 2010 [Page 35] =0C --Apple-Mail-6--53398945-- From darlewis@cisco.com Fri Feb 12 16:54:37 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 0385428C1E0 for ; Fri, 12 Feb 2010 16:54:37 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -8.299 X-Spam-Level: X-Spam-Status: No, score=-8.299 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, MANGLED_TOOL=2.3, RCVD_IN_DNSWL_HI=-8] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id bXbmaeXIlABc for ; Fri, 12 Feb 2010 16:54:36 -0800 (PST) Received: from sj-iport-4.cisco.com (sj-iport-4.cisco.com [171.68.10.86]) by core3.amsl.com (Postfix) with ESMTP id 4B1AD3A792A for ; Fri, 12 Feb 2010 16:54:36 -0800 (PST) Authentication-Results: sj-iport-4.cisco.com; dkim=neutral (message not signed) header.i=none X-IronPort-AV: E=Sophos;i="4.49,464,1262563200"; d="scan'208";a="87702454" Received: from sj-core-2.cisco.com ([171.71.177.254]) by sj-iport-4.cisco.com with ESMTP; 13 Feb 2010 00:55:56 +0000 Received: from [10.21.74.176] ([10.21.74.176]) by sj-core-2.cisco.com (8.13.8/8.14.3) with ESMTP id o1D0tuEM022433; Sat, 13 Feb 2010 00:55:56 GMT Mime-Version: 1.0 (Apple Message framework v1077) Content-Type: text/plain; charset=us-ascii From: Darrel Lewis In-Reply-To: <5D6E81D4-77A1-4A20-B8AD-664F9316A969@cisco.com> Date: Fri, 12 Feb 2010 16:55:56 -0800 Content-Transfer-Encoding: quoted-printable Message-Id: <9E784D3F-1B42-4E2E-9585-E1AECF1612D7@cisco.com> References: <5D6E81D4-77A1-4A20-B8AD-664F9316A969@cisco.com> To: Darrel Lewis X-Mailer: Apple Mail (2.1077) Cc: lisp@ietf.org Subject: Re: [lisp] Proposed draft-ietf-lisp-interworking-01 draft X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 13 Feb 2010 00:54:37 -0000 I just noticed some formatting bugs on the section numbers. Will fix = and post corrections. But that shouldn't effect content for review. -Darrel On Feb 12, 2010, at 3:16 PM, Darrel Lewis wrote: >=20 > Here is an updated version of the LISP Interworking specification that = I'd like to > publish to the Internet Drafts repository. >=20 > The main addition to the draft is a the introduction of an optional = network element called the "Proxy Egress Tunnel Router" or PETR. =20 >=20 > Both html diffs and the full text of the new draft are attached. >=20 > Comments appreciated. I'd like to get this posted next Friday (by > Feb 22nd). >=20 > -Darrel > (for the other Interworking authors: Dino, Dave, and Vince) >=20 > = _______________________________________________ > lisp mailing list > lisp@ietf.org > https://www.ietf.org/mailman/listinfo/lisp From darlewis@cisco.com Fri Feb 12 17:27:22 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id AC42328C255 for ; Fri, 12 Feb 2010 17:27:22 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -7.165 X-Spam-Level: X-Spam-Status: No, score=-7.165 tagged_above=-999 required=5 tests=[AWL=1.133, BAYES_00=-2.599, MANGLED_TOOL=2.3, RCVD_IN_DNSWL_HI=-8] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kvats8-rxz+8 for ; Fri, 12 Feb 2010 17:27:18 -0800 (PST) Received: from sj-iport-5.cisco.com (sj-iport-5.cisco.com [171.68.10.87]) by core3.amsl.com (Postfix) with ESMTP id 05D3A28C254 for ; Fri, 12 Feb 2010 17:27:14 -0800 (PST) Authentication-Results: sj-iport-5.cisco.com; dkim=neutral (message not signed) header.i=none X-Files: draft-ietf-lisp-Interworking-00-to-01-diff, draft-ietf-lisp-interworking-01.txt : 60364, 45944 X-IronPort-AV: E=Sophos;i="4.49,464,1262563200"; d="txt'?scan'208,217";a="150840375" Received: from sj-core-4.cisco.com ([171.68.223.138]) by sj-iport-5.cisco.com with ESMTP; 13 Feb 2010 01:28:34 +0000 Received: from [10.21.74.176] ([10.21.74.176]) by sj-core-4.cisco.com (8.13.8/8.14.3) with ESMTP id o1D1SUT5005688; Sat, 13 Feb 2010 01:28:30 GMT Mime-Version: 1.0 (Apple Message framework v1077) Content-Type: multipart/mixed; boundary=Apple-Mail-8--45498354 From: Darrel Lewis In-Reply-To: <5D6E81D4-77A1-4A20-B8AD-664F9316A969@cisco.com> Date: Fri, 12 Feb 2010 17:28:30 -0800 Message-Id: <0715C8C7-822B-4C32-B47C-A64458B00B3C@cisco.com> References: <5D6E81D4-77A1-4A20-B8AD-664F9316A969@cisco.com> To: Darrel Lewis X-Mailer: Apple Mail (2.1077) Cc: lisp@ietf.org Subject: Re: [lisp] Proposed draft-ietf-lisp-interworking-01 draft X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 13 Feb 2010 01:27:22 -0000 --Apple-Mail-8--45498354 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Corrected diff and proposed draft attached. Thanks, -Darrel --Apple-Mail-8--45498354 Content-Disposition: attachment; filename=draft-ietf-lisp-Interworking-00-to-01-diff Content-Type: application/octet-stream; name="draft-ietf-lisp-Interworking-00-to-01-diff" Content-Transfer-Encoding: 7bit wdiff draft-ietf-lisp-interworking-00.txt draft-ietf-lisp-interworking-01.txt 
Network Working Group                                           D. Lewis
Internet-Draft                                                  D. Meyer
Intended status: Experimental                               D. Farinacci
Expires: November 27, 2009 August 17, 2010                                       V. Fuller
                                                     Cisco Systems, Inc.
                                                            May 26, 2009
                                                       February 13, 2010

                  Interworking LISP with IPv4 and IPv6
                    draft-ietf-lisp-interworking-00
                  draft-ietf-lisp-interworking-01.txt

Abstract

   This document describes techniques for allowing sites running the
   Locator/ID Separation Protocol (LISP [LISP]) to interoperate with
   Internet sites (using either IPv4, IPv6, or both) which are not
   running LISP.  A fundamental property of LISP speaking sites is that
   they use Endpoint Identifiers (EIDs), rather than traditional IP
   addresses, in the source and destination fields of all traffic they
   emit or receive.  While EIDs are syntactically identical to IPv4 or
   IPv6 addresses, routes for them are not carried in the global routing
   system so an interoperability mechanism is needed for non-LISP-
   speaking sites to exchange traffic with LISP-speaking sites.  This
   document introduces three such mechanisms: the first uses a new
   network element, the LISP Proxy Ingress Tunnel Routers (PITR)
   (Section 5) to act as a intermediate LISP Ingress Tunnel Router (ITR)
   for non-LISP-speaking hosts while the second adds Network Address
   Translation (NAT) functionality to LISP Ingress and LISP Egress
   Tunnel Routers (xTRs) to substitute routable IP addresses for non-
   routable EIDs.  Finally, this document introduces a Proxy Egress
   Tunnel Router (PETR) to solve cases where a LISP site cannot send a
   packet which has as its source address a non-routable EID

Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
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   Drafts.

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   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on November 27, 2009. August 17, 2010.

Copyright Notice

   Copyright (c) 2009 2010 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 (http://trustee.ietf.org/license-info). document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Abstract

   This  Code Components extracted from this document describes techniques for allowing sites running the
   Locator/ID Separation Protocol (LISP [LISP]) to interoperate with
   Internet sites not running LISP.  A fundamental property of LISP-
   speaking sites is that they use Endpoint Identifiers (EIDs), rather
   than traditional IP addresses, must
   include Simplified BSD License text as described in Section 4.e of
   the source Trust Legal Provisions and destination fields
   of all traffic they emit or receive.  While EIDs are syntactically
   identical to IP addresses, routes for them are not carried in the
   global routing system so an interoperability mechanism is needed for
   non-LISP-speaking sites to exchange traffic with LISP-speaking sites.
   This document introduces two such mechanisms: the first uses a new
   network element, the LISP Proxy Tunnel Router (PTR) (Section 5) to
   act provided without warranty as a intermediate LISP Ingress Tunnel Router (ITR) for non-LISP-
   speaking hosts while
   described in the second adds Network Address Translation
   (NAT) functionality to LISP Ingress and LISP Egress Tunnel Routers
   (xTRs) to substitute routable IP addresses for non-routable EIDs. BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3  4
   2.  LISP Interworking Models . . . . . . . . . . . . . . . . . . .  3  6
   3.  Definition of Terms  . . . . . . . . . . . . . . . . . . . . .  5  8
   4.  Routable EIDs  . . . . . . . . . . . . . . . . . . . . . . . .  6 11
     4.1.  Impact on Routing Table  . . . . . . . . . . . . . . . . .  6 11
     4.2.  Requirement for using BGP  . . . . . . . . . . . . . . . .  6 11
     4.3.  Limiting the Impact of Routable EIDs . . . . . . . . . . .  6 11
     4.4.  Use of Routable EIDs for Testing LISP  . . . . . . . . . .  7 11
   5.  Proxy Ingress Tunnel Routers . . . . . . . . . . . . . . . . . . . . .  7 13
     5.1.  PTR  PITR EID announcements . . . . . . . . . . . . . . . . . .  7 13
     5.2.  Packet Flow with PTRs PITRs . . . . . . . . . . . . . . . . . .  8 13
     5.3.  Scaling PTRs . PITRs  . . . . . . . . . . . . . . . . . . . . . .  9 14
     5.4.  Impact of the PTRs PITRs placement in the network . . . . . . .  9 15
     5.5.  Benefit to Networks Deploying PTRs . PITRs  . . . . . . . . . . .  9 15
   6.  LISP-NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 16
     6.1.  LISP-NAT for LISP-NR addressed hosts . . . . . . . . . . . 10 16
     6.2.  LISP Sites with Hosts using RFC 1918 Addresses Sending
           to non-LISP Sites  . . . . . . . . . . . . . . . . . . . . 11 17
     6.3.  LISP Sites with Hosts using RFC 1918 Addresses
           Communicating to Other LISP Sites  . . . . . . . . . . . . 11 17
     6.4.  LISP-NAT and multiple EIDs . . . . . . . . . . . . . . . . 12 18
     6.5.  When LISP-NAT and PTRs Together PITRs used by the same LISP Site . . . . 18
   7.  Proxy Egress Tunnel Routers  . . . . . . . . . . . . . . 12
   7. . . . 20
     7.1.  Packet Flow with Proxy Egress Tunnel Routers . . . . . . . 20
   8.  Discussion of Proxy ITRs (PITRs), LISP-NAT, and Proxy-ETRs
       (PETRs)  . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
     8.1.  How Proxy-ITRs and Proxy-ETRs Interact . . . . . . . . . . 22
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   8. 23
   10. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 13
   9. 24
   11. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 14
   10. 25
   12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     10.1. 26
     12.1. Normative References . . . . . . . . . . . . . . . . . . . 14
     10.2. 26
     12.2. Informative References . . . . . . . . . . . . . . . . . . 14 26
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 27

1.  Introduction

   This document describes two mechanisms for interoperation between
   LISP [LISP] sites, which use non-globally-routed EIDs, and non-LISP
   sites: use of PTRs, PITRs, which create highly-aggregated routes to EID
   prefixes for non-LISP sites to follow; and the follow.  The use of NAT by LISP ETRs
   when communicating with non-LISP hosts.  And finally the use of Proxy
   Egress Tunnel routers (PETRs) LISP for sites relying on PITRs and
   which are faced with certain restrictions.

   A key behavior of the separation of Locators and End-Point-IDs is
   that EID prefixes are not advertised to the Internet's Default Free
   Zone (DFZ).  Specifically, only RLOCs are carried in the Internet's
   DFZ.  Existing Internet sites (and their hosts) who do not
   participate in the LISP system must still be able to reach sites
   numbered from this non routed EID space.  This draft describes a set
   of mechanisms that can be used to provide reachability between sites
   that are LISP-capable and those that are not.  This document
   introduces two three such mechanisms: the mechanisms.  The first uses a new network
   element, the LISP Proxy Ingress Tunnel Router (PTR) (PITR) (Section 5) to
   act as a intermediate LISP Ingress Tunnel Router (ITR) for non-LISP-speaking
   hosts while the non-LISP-
   speaking hosts.  The second adds a form of Network Address
   Translation (NAT) functionality to Tunnel Routers (xTRs) to
   substitute routable IP addresses for non-routable EIDs.

   More detailed descriptions of these mechanisms and the  The final
   network element is the LISP Proxy Egress Tunnel Routers (PETR), which
   act as an intermediate Egress Tunnel Router (ETR) for LISP sites who
   are using PITRs but need assistance in reaching non-LISP sites.

   More detailed descriptions of these mechanisms and the network
   elements involved may be found in the following sections:

   - Section 2 describes the different cases where interworking
   mechanisms are needed

   - Section 3 defines terms used throughout the document

   - Section 4 describes the relationship between the new EID prefix
   space and the IP address space used by the current Internet

   - Section 5 introduces and describes the operation of PTRs Proxy-ITRs

   - Section 6 defines how NAT is used by ETRs to translate non-routable
   EIDs into routable IP addresses.

   - Section 7 introduces and describes the operations of Proxy-ETRs

   - Section 8 describes the relationship between asymmetric and
   Symmetric interworking mechanisms (Proxy-ITRs and Proxy-ETRs vs LISP-
   NAT)

   Note that any successful interworking model should be independent of
   any particular EID-to-RLOC mapping algorithm.  This document does not
   comment on the value of any of the particular LISP mapping system. systems.

2.  LISP Interworking Models

   There are 4 unicast connectivity cases which describe how sites can
   communicate with each other:

   1.  Non-LISP site to Non-LISP site

   2.  LISP site to LISP site

   3.  LISP site to Non-LISP site

   4.  Non-LISP site to LISP site

   Note that while Cases 3 and 4 seem similar, there are subtle
   differences due to the way communications are originated.

   The first case is the Internet as we know it today and as such will
   not be discussed further here.  The second case is documented in
   [LISP] and, hence, there are no new interworking requirements because
   there are no new protocol requirements placed on intermediate non-
   LISP routers.

   In case 3, LISP site to Non-LISP site, a LISP site can (in most
   cases) send packets to a non-LISP site because the non-LISP site
   prefixes are routable.  The non-LISP site need not do anything new to
   receive packets.  The only action the LISP site needs (with two
   possible caveats introduced below) to take is to know when not to LISP-
   encapsulate
   LISP-encapsulate packets.  This can be achieved via two mechanisms:

   1.  At the ITR in the source site, if the destination of an IP packet
       is found to match a prefix from the BGP routing table, then the
       site is directly reachable by the BGP core that exists and
       operates today.

   2.  Second, if (from the perspective of the ITR at the source site)
       the destination address of an IP address is not found in the EID-
       to-RLOC mapping database, the ITR could infer that it is not a
       LISP-capable site, and decide to not LISP-encapsulate the packet.

   3.  There are two potential caveats involved with Case 3, where there
       could be some situations where (unencapsualted) packets
       originated by a LISP site may not be forwarded to a non-LISP
       site.  One of these caveats (uRPF check failure) are detailed in
       Section 9 (Security Considerations).  The second caveat (protocol
       traversal) is reviewed in section 7, (Proxy-Egress Tunnel
       Routers).

   Case 4, typically the most challenging, occurs when a host at a non-LISP non-
   LISP site wishes to send traffic to a host at a LISP site.  If the
   source host uses a (non-globally-routable) EID as the destination IP
   address, the packet is forwarded inside the source site until it
   reaches a router which cannot forward it, at which point the traffic
   is dropped.  For traffic not to be dropped, either some route must be
   exist for the destination EID outside of LISP-speaking part of the
   network or an alternate mechanism must be in place.  Section 5 (PTRs)
   (PITRs) and Section 6 (LISP-NAT) describe two such mechanisms.

   Note that case 4 includes packets returning to the LISP Site in case
   3.

3.  Definition of Terms

   Endpoint ID (EID):  Endpoint ID (EID): A 32- 32-bit (for IPv4) or 128-bit
      (for IPv6) value used in the source and destination address fields
      of the first (most inner) LISP header of a packet.  A packet that is emitted by  The host
      obtains a system contains EIDs in its
      headers and LISP headers are prepended only when destination EID the packet
      reaches same way it obtains an Ingress Tunnel Router (ITR) on the data path to the destination EID.

   EID-Prefix Aggregate:  A set of EID-prefixes said
      address today, for example through a DNS lookup or SIP exchange.
      The source EID is obtained via existing mechanisms used to be aggregatable
      in the [RFC4632] sense.  That is, an EID-Prefix aggregate set a
      host's "local" IP address.  An EID is
      defined allocated to be a single contiguous power-of-two host from an
      EID-prefix block.
      Such a block associated with the site where the host is characterized
      located.  An EID can be used by a prefix and host to refer to other hosts.
      EIDs MUST NOT be used as LISP RLOCs.  Note that EID blocks may be
      assigned in a length.

   Routing Locator (RLOC):  An IP address hierarchical manner, independent of a LISP tunnel router.  It
      is the output network
      topology, to facilitate scaling of a EID-to-RLOC the mapping lookup.  An database.  In
      addition, an EID block assigned to a site may have site-local
      structure (subnetting) for routing within the site; this structure
      is not visible to the global routing system.  When used in
      discussions with other Locator/ID separation proposals, a LISP EID
      will be called a "LEID".  Throughout this document, any references
      to "EID" refers to an LEID.

   EID-Prefix:  EID-prefix: A power-of-2 block of EIDs which are
      allocated to a site by an address allocation authority.  EID-
      prefixes are associated with a set of RLOC addresses which make up
      a "database mapping".  EID-prefix allocations can be broken up
      into smaller blocks when an RLOC set is to be associated with the
      smaller EID- prefix.  A globally routed address block (whether PI
      or PA) is not an EID-prefix.  However, a globally routed address
      block may be removed from global routing and reused as an EID-
      prefix.  A site that receives an explicitly allocated EID-prefix
      may not use that EID-prefix as a globally routed prefix assigned
      to RLOCs

   EID-Prefix Aggregate:  A set of EID-prefixes said to be aggregatable
      in the [RFC4632] sense.  That is, an EID-Prefix aggregate is
      defined to be a single contiguous power-of-two EID-prefix block.
      Such a block is characterized by a prefix and a length.  Provider
      Independent (PI) Addresses: an address block assigned from a pool
      where blocks are not associated with any particular location in
      the network (e.g. from a particular service provider), and is
      therefore not topologically aggregatable in the routing system.

   Routing Locator (RLOC):  The IPv4 or IPv6 address of an egress tunnel
      router (ETR).  It is the output of a EID-to-RLOC mapping lookup.
      An EID maps to one or more RLOCs.  Typically, RLOCs are numbered
      from topologically-
      aggregatable topologically-aggregatable blocks and that are assigned to a site
      at each point to which it attaches to the global Internet; where
      the topology is defined by the connectivity of provider networks,
      RLOCs can be thought of as Provider Aggregatable (PA) PA addresses.  Multiple RLOCs can be
      assigned to the same ETR device or to multiple ETR devices at a
      site.

   EID-to-RLOC Mapping:  A binding between an EID and the RLOC-set that
      can be used to reach the EID.  We use the term "mapping" in this
      document to refer to a EID-to-RLOC mapping.

   EID Prefix Reachability:  An EID prefix is said to be "reachable" if
      one or more of its locators are reachable.  That is, an EID prefix
      is reachable if the ETR (or its proxy) is reachable.

   Default Mapping:  A Default Mapping is a mapping entry for EID-prefix
      0.0.0.0/0.  It maps to a locator-set used for all EIDs in the
      Internet.  If there is a more specific EID-prefix in the mapping
      cache it overrides the Default Mapping entry.  The Default Mapping
      route can be learned by configuration or from a Map-Reply message
      [LISP].

   LISP Routable (LISP-R) Site:  A LISP site whose addresses are used as
      both globally routable IP addresses and LISP EIDs.

   LISP Non-Routable (LISP-NR) Site:  A LISP site whose addresses are
      EIDs only, these EIDs are not found in the legacy Internet routing
      table.

   LISP Proxy Ingress Tunnel Router (PTR):  PTRs (PITR):  PITRs are used to provide
      interconnectivity between sites which use LISP EIDs and those
      which do not.  They act as a gateway between the Legacy Internet
      and the LISP enabled Network.  A given PTR PITR advertises one or more
      highly aggregated EID prefixes into the public Internet and acts
      as the ITR for traffic received from the public Internet.  LISP
      Proxy Ingress Tunnel Routers are described in Section 5.

   LISP Network Address Translation (LISP-NAT):  Network Address
      Translation between EID space assigned to a site and RLOC space
      also assigned to that site.  LISP Network Address Translation is
      described in Section 6.

    EID Sub Namespace:  A power-of-two block of aggregatable locators
      set aside for

   LISP interworking.

4.  Routable EIDs

   An obvious Proxy Egress Tunnel Router (PETR):  PETRs are used to provide a
      LISP site's ITRs the ability to send traffic to non-LISP sites in
      cases where unencapsualted packets (the default mechanism) would
      fail to be delivered.  PETRs are implemented by having an ITR
      encapsulate all non-LISP destined traffic to a pre-configured
      PETR.  LISP Proxy Egress Tunnel Routers are described in
      Section 7.

    EID Sub Namespace:  A power-of-two block of aggregatable locators
      set aside for LISP interworking.

4.  Routable EIDs

   An obvious way to achieve interworking between LISP and non-LISP
   hosts is to simply announce EID prefixes into the DFZ, much like
   routing system, effectively treating them as "Provider Independent
   (PI)" prefixes.  Doing this is undesirable as it defeats one of the
   primary goals of LISP - to reduce global routing system state.

4.1.  Impact on Routing Table

   If EID prefixes are announced into the DFZ, the impact is similar to
   the case in which LISP has not been deployed, because these EID
   prefixes will be no more aggregatable than existing PI addressing.
   This behavior is not desirable and such a mechanism is not viewed as
   a viable long term solution.

4.2.  Requirement for using BGP

   Non-LISP sites today use BGP to, among other things, enable ingress
   traffic engineering.  Relaxing this requirement is another primary
   design goal of LISP.

4.3.  Limiting the Impact of Routable EIDs

   Two schemes are proposed to limit the impact of having EIDs announced
   in the current global Internet routing table:

   1.  Section 5 discusses the LISP Proxy Tunnel Router, an approach
       that provides ITR functionality to bridge LISP-capable and non-LISP-
      capable non-
       LISP-capable sites.

   2.  Section 6 discusses another approach, LISP-NAT, in which NAT
       [RFC2993] is combined with ITR functionality to limit the the
       impact of routable EIDs on the Internet routing infrastructure.

4.4.  Use of Routable EIDs for Testing LISP

   A primary design goal for LISP (and other Locator/ID separation
   proposals) is to facilitate topological aggregation of addresses and,
   thus, decrease global routing system state.  Another goal is to
   achieve the benefits of improved aggregation as soon as possible.
   Advertising
   Sites advertising routes for LISP EID prefixes into the global
   routing system is therefore not recommended.

   That being said, single homed sites (or multi-homed sites that are
   not leaking more specific exceptions) and that are already using
   provider-aggregated prefixes can use these prefixes as LISP EIDs
   without adding state to the routing system; in other words, such
   sites do not cause additional prefixes to be advertised.  For such
   sites, connectivity to a non-LISP sites does not require interworking
   machinery because the "PA" EIDs are already routable. routable (they are
   effectively LISP-R type sites).  Their EIDs are found in the LISP
   mapping system, and their (aggregate) PA prefix(es) are found in the
   DFZ Internet.

   The continued announcements of an existing site's Provider
   Independent (or "PI") prefix(s) is of course under control of that
   site, and some period of transition where a site is is found both in
   the LISP mapping system and as a discrete prefix in the Internet
   routing system may be a viable transition strategy.  Care should be
   taken not to advertise additional more specific LISP EID prefixes
   into the DFZ.

5.  Proxy Ingress Tunnel Routers

   Proxy Ingress Tunnel Routers (PTRs) (PITRs) allow for non-LISP sites to
   communicate with LISP-NR sites.  A PTR PITR is a new network element that
   shares many characteristics with the LISP ITR.  PTRs  PITRs allow non-LISP
   sites to send packets to LISP-NR sites without any changes to
   protocols or equipment at the non-LISP site.  PTRs  PITRs have two primary
   functions:

   Originating EID Advertisements:  PTRs  PITRs advertise highly aggregated
      EID-prefix space on behalf of LISP sites to so that non-LISP sites
      can reach them.

   Encapsulating Legacy Internet Traffic:  PTRs  PITRs also encapsulate non-
      LISP Internet traffic into LISP packets and route them towards
      their destination RLOCs.

5.1.  PTR  PITR EID announcements

   A key part of PTR PITR functionality is to advertise routes for highly-
   aggregated EID prefixes into part of the global routing system.
   Aggressive aggregation is performed to minimize the number of new
   announced routes.  In addition, careful placement of PTRs PITRs can
   greatly reduce the scope of these new routes.  To this end, PTRs PITRs
   should be deployed close to non-LISP-speaking rather than close to
   LISP sites.  Such deployment not only limits the scope of EID-prefix
   route advertisements, it also also allows traffic forwarding load to
   be spread among many PTRs. PITRs.

5.2.  Packet Flow with PTRs PITRs

   Packets from a non-LISP site can reach a LISP-NR site with the aid of
   a PTR. PITR.  By advertising a route for a particular EID prefix into the
   global routing system, traffic destined for that EID prefix is routed
   to the PTR, PITR, which then performs LISP encapsulation.  Once
   encapsulated, traffic packets use the LISP (outer) header's
   destination address to reach the destination ETR.

   What follows is an example of the path a packet would take when using
   a PTR. PITR.  In this example, the LISP-NR site is given the EID prefix
   240.0.0.0/24.  For the purposes of this example, this prefix and no
   covering aggregate is present in the global routing system.  In other
   words, if a packet with this destination were to reach a router in
   the "Default Free Zone", it would be dropped.

   A full protocol exchange example follows:

   1.  Source host makes a DNS lookup EID for destination, and gets
       240.1.1.1 in return.

   2.  Source host has a default route to customer Edge (CE) router and
       forwards the packet to the CE.

   3.  The CE has a default route to its Provider Edge (PE) router, and
       forwards the packet to the PE.

   4.  The PE has route to 240.0.0.0/24 and the next hop is the PTR. PITR.

   5.  The PTR PITR has or acquires a mapping for 240.1.1.1 and LISP
       encapsulates, the packet now has a destination address of the
       RLOC.  The source address of this encapsulated packet is the
       PTR's
       PITR's RLOC.

   6.  The PTR PITR looks up the RLOC, and forwards LISP packet to the next
       hop.

   7.  The ETR decapsulates the packet and delivers the packet to the
       240.1.1.1 host in the destination LISP site.

   8.  Packets from host 240.1.1.1 will flow back through the LISP
       site's ITR.  Such packets are not encapsulated because the ITR
       knows that the destination (the original source) is a non-LISP
       site.  The ITR knows this because it can check the LISP mapping
       database for the destination EID, and on a failure determine that
       the destination site is not LISP enabled.

   9.  Packets are then routed natively and directly to the destination
       (original source) site.

   Note that in this example the return path is asymmetric, so return
   traffic will not go back through the PTR. PITR.  This is because the
   LISP-NR site's ITR will discover that the originating site is not a
   LISP site, and not encapsulate the returning packet (see [LISP] for
   details of ITR behavior).

   The asymmetric nature of traffic flows allows the PTR PITR to be
   relatively simple - it will only have to encapsulate LISP packets.

5.3.  Scaling PTRs

   PTRs PITRs

   PITRs attract traffic by announcing the LISP EID namespace into parts
   of the non-LISP-speaking global routing system.  There are several
   ways that a network could control how traffic reaches a particular
   PTR
   PITR to prevent it from receiving more traffic than it can handle:

   First, the PTR's PITR's aggregate routes might be selectively announced,
   giving a coarse way to control the quantity of traffic attracted by
   that PTR. PITR.

   Second, the same address might be announced by multiple PTRs PITRs in
   order to share the traffic using IP Anycast.  The asymmetric nature
   of traffic flows allows the PTR PITR to be relatively simple - it will
   only have to encapsulate LISP packets.

5.4.  Impact of the PTRs PITRs placement in the network

   There are several approaches that a network could take in placing
   PTRs.
   PITRs.  Placing the PTR PITR near the ingress of traffic allows for the
   communication between the non-LISP site and the LISP site to have the
   least "stretch" (i.e. the least number of forwarding hops when
   compared to an optimal path between the sites).

   Some proposals, for example CRIO [CRIO], have suggested grouping PTRs
   PITRs near an arbitrary subset of ETRs and announcing a 'local'
   subset of EID space.  This model cannot guarantee minimum stretch if
   the EID prefix route advertisement points are changed (such a change
   might occur if a site adds, removes, or replaces one or more ISPs
   connections).

5.5.  Benefit to Networks Deploying PTRs PITRs

   When traffic destined for LISP-NR site arrives and is encapsulated at
   a PTR, PITR, a new LISP packet header is pre-pended.  This causes the
   packet's destination to be set to the destination site RLOC.  Because
   traffic is thus routed towards RLOCs, it can potentially better
   follow the network's traffic engineering policies (such as closest
   exit routing).  This also means that providers who are not default-
   free and do not deploy PTRs PITRs end up sending more traffic to expensive
   transit links rather than to RLOC addresses, to which they may have
   settlement-free peering.  For large transit providers, deploying PTRs
   PITRs may attract more traffic, and therefore more revenue, from
   their customers.

6.  LISP-NAT

   LISP Network Address Translation (LISP-NAT) is a limited form of NAT
   [RFC2993].  LISP-NAT is designed to enable the interworking of non-
   LISP sites and LISP-NR sites by ensuring that the LISP-NR's site
   addresses are always routable.  LISP-NAT accomplishes this by
   translating a host's source address from an 'inner' value to an
   'outer' value and keeping this translation in a table that it can
   reference for subsequent packets.

   In addition, existing RFC 1918 [RFC1918] sites can use LISP-NAT to
   talk to both LISP or non-LISP sites.

   The basic concept of LISP-NAT is that when transmitting a packet, the
   ITR replaces a non-routable EID source address with a routable source
   address, which enables packets to return to the site.

   There are two main cases that involve LISP-NAT:

   1.  Hosts at LISP sites that use non-routable global EIDs speaking to
       non-LISP sites using global addresses.

   2.  Hosts at LISP sites that use RFC 1918 private EIDs speaking to
       other sites, who may be either LISP or non-LISP.

   Note that LISP-NAT is not needed in the case of LISP-R (routable
   global EIDs) sources.  This case occurs when a site is announcing its
   prefix into both the LISP mapping system as well as the Internet DFZ.
   This is because the LISP-R source's address is routable, and return
   packets will be able to natively reach the site.

6.1.  LISP-NAT for LISP-NR addressed hosts

   LISP-NAT allows a host with a LISP-NR EID to communicate with non-
   LISP hosts by translating the LISP-NR EID to a globally unique
   address.  This globally unique address may be a either a PI or PA
   address.

   An example of this translation follows.  For this example, a site has
   been assigned a LISP-NR EID of 220.1.1.0/24.  In order to utilize
   LISP-NAT, the site has also been provided the PA EID of
   128.200.1.0/24, and uses the first address (128.200.1.1) as the
   site's RLOC.  The rest of this PA space (128.200.1.2 to
   128.200.1.254) is used as a translation pool for this site's hosts
   who need to communicate with non-LISP hosts.

   The translation table might look like the following:

     Site NR-EID    Site R-EID      Site's RLOC    Translation Pool
   =========================================================================
     ===================================================================
     220.1.1.0/24   128.200.1.0/24  128.200.1.1    128.200.1.2 - 128.200.1.254    128.200.1.2-254

                    Figure 1: Example Translation Table

   The Host 220.1.1.2 sends a packet destined for a non-LISP site to its
   default route (the ITR).  The ITR receives the packet, and determines
   that the destination is not a LISP site.  How the ITR makes this
   determination is up to the ITRs implementation of the EID-to-RLOC
   mapping system used (see, for example [LISP-ALT]).

   The ITR then rewrites the source address of the packet from 220.1.1.2
   to 128.200.1.2, which is the first available address in the LISP-R
   EID space available to it.  The ITR keeps this translation in a table
   in order to reverse this process when receiving packets destined to
   128.200.1.2.

   Finally, when the ITR forwards this packet without encapsulating it,
   it uses the entry in its LISP-NAT table to translate the returning
   packets' destination IPs to the proper host.

6.2.  LISP Sites with Hosts using RFC 1918 Addresses Sending to non-LISP
      Sites

   In the case where RFC 1918 addressed hosts desire to communicate with
   non-LISP hosts the LISP-NAT implementation acts much like an existing
   IPv4 NAT device.  The ITR providing the NAT service must use LISP-R
   EIDs for its global pool as well as providing all the standard NAT
   functions required today.

   The source of the packet must be translated to a LISP-R EID in a
   manner similar to Section 6, and this packet must be forwarded to the
   ITR's next hop for the destination, without LISP encapsulation.

6.3.  LISP Sites with Hosts using RFC 1918 Addresses   Communicating to
      Other LISP Sites

   LISP-NAT allows a host with a RFC 1918 address to communicate with
   LISP hosts by translating the RFC 1918 address to a LISP EID.  After
   translation, the communication between source and destination ITR and
   ETRs continues as described in [LISP].

   An example of this translation and encapsulation follows.  For this
   example, a host has been assigned a RFC 1918 address of 192.168.1.2.
   In order to utilize LISP-NAT, the site also has been provided the
   LISP-R EID of 192.0.2.0/24, and uses the first address (192.0.2.1) as
   the site's RLOC.  The rest of this PA space (192.0.2.2 to
   192.0.2.254) is used as a translation pool for this site's hosts who
   need to communicate with both non-LISP and LISP hosts.

   The Host 192.168.1.2 sends a packet destined for a non-LISP site to
   its default route (the ITR).  The ITR receives the packet and
   determines that the destination is a LISP site.  How the ITR makes
   this determination is up to the ITRs implementation of the EID/RLOC
   mapping system.

   The ITR then rewrites the source address of the packet from
   192.168.1.2 to 192.0.2.2, which is the first available address in the
   LISP EID space available to it.  The ITR keeps this translation in a
   table in order to reverse this process when receiving packets
   destined to 192.0.2.2.

   The ITR then LISP encapsulates this packet (see [LISP] for details).
   The ITR uses the site's RLOC as the LISP outer header's source and
   the translation address as the LISP inner header's source.  Once it
   decapsulates returning traffic, it uses the entry in its LISP-NAT
   table to translate the returning packet's destination IP address and
   then forward to the proper host.

6.4.  LISP-NAT and multiple EIDs

   When a site has two addresses that a host might use for global
   reachability, care must be chosen on which EID is found in DNS.  For
   example, whether applications such as DNS use the LISP-R EID or the
   LISP-NR EID.  This problem exists for NAT in general, but the
   specific issue described above is unique to LISP.  Using PTRs PITRs can
   mitigate this problem, since the LISP-NR EID can be reached in all
   cases.

6.5.  When LISP-NAT and PTRs Together PITRs used by the same LISP Site

   With LISP-NAT, there are two EIDs possible for a given host, the
   LISP-R EID and the LISP-NR EID.  When a site has two addresses that a
   host might use for global reachability, name-to-address directories
   may need to be modified.

   This problem, global addressability, exists for NAT in general, but
   the specific issue described above is unique to LOC/ID split schemes.
   Some schemes [ref: 6-1 proxy] have suggested running a separate DNS
   instance for legacy types of EIDs.  This solves the problem but
   introduces complexity for the site.  Alternatively, using PTRs PITRs can
   mitigate this problem, because the LISP-NR EID can hbe be reached in all
   cases. all
   cases.

   In summary, there are two options for interworking LISP with IPv4 and
   V6.  In the NAT case the LISP site can use NAT and manage the
   transition on its own.  In the PITR case, we add a new network
   element called a PITR that can relieve that burden on the site, with
   the downside of potentially adding stretch to sites trying to reach
   the LISP site.

7.  Proxy Egress Tunnel Routers

   Proxy Egress Tunnel Routers (PETRs) allow for LISP-NR sites to
   communicate with non-LISP sites in the case where the access network
   does not allow for the LISP-NR site send packets with the source
   address of the site's EID(s).  A PETR is a new network element that
   conceptually acts as an ETR for traffic destined to non-LISP sites.
   This also has the effect of allowing an ITR avoid having to decide
   whether to encapsulate packets or not - it will always encapsulate
   packets.  Packets destined to LISP sites will travel directly to that
   site's ETR, all other packets will be sent to the site's PETR.

   There are two primary reasons why sites would want to utilize a PETR:

   Avoiding strict uRPF failures:  Some provider's access networks
      require the source of the packets emitted to be within the
      addressing scope of the access networks. (see section 9)

   Traversing a different IP Protocol:  A LISP site may want to transmit
      packets to a non-LISP site where the some of the intermediate
      network does not support an IP protocol (v4 or v6).  PETRs can
      allow this LISP site's data to 'hop over' this by utilizing LISP's
      support for mixed protocol encapsulation.

7.1.  Packet Flow with Proxy Egress Tunnel Routers

   Packets from a LISP site can reach a non-LISP site with the aid of a
   Proxy-ETR (or PETR).  An ITR is simply configured to send all non-
   LISP traffic, which it normally would have forwarded natively (non-
   encapsulated), to a PETR.  Note that this outer encapsulation may be
   in another IP protocol than the (inner) encapsulated data.  Traffic
   then uses use the LISP (outer) header's destination address to reach
   the destination PETR.

   A PETR should verify the (inner) source EID of the packet at time of
   decapsulation in order to verify that this is from a configured LISP
   site.  This is to prevent spoofed inner sources from being
   encapsulated through the Proxy-ETR.

   What follows is an example of the path a packet would take when using
   a PETR.  In this example, the LISP-NR site is given the EID prefix
   240.2.0.0/24, and it is trying to reach host at a non-LISP site with
   the IP prefix of 192.0.2.0/24.  For the purposes of this example, the
   destination is a non-LISP site and 192.0.2.0/24 is found in the
   Internet's routing system.

   A full protocol exchange example follows:

   1.  Source host makes a DNS lookup for the destination, and gets
       192.0.2.100 (a non-LISP site) in return.

   2.  Source host has a default route to customer Edge (CE) router and
       forwards the packet towards the CE.

   3.  The CE is a LISP ITR, and is configured to encapsulate traffic
       destined for non-lisp sites to a Proxy-ETR.

   4.  The Proxy ETR decapsulates the LISP packet and forwards the
       original packet to its next hop.

   5.  The packet is then routed natively and directly to the
       destination (non-LISP) site 192.0.2.0/24.

   Note that in this example the return path is asymmetric, so return
   traffic will not go back through the Proxy-ITR.  This means that in
   order to reach LISP-NR sites, non-lisp sites must still use Proxy
   ITRs.

8.  Discussion of Proxy ITRs (PITRs), LISP-NAT, and Proxy-ETRs (PETRs)

   In summary, there are two three options for interworking LISP with non-
   LISP Sites (for both IPv4 and
   V6. IPv6).  In the NAT case LISP-NAT option the LISP
   site can use NAT and manage and control the
   transition interworking on its own.  In the PTR PITR
   case, we add a new network element
   called a PTR that can relieve that burden on the site,
   with the
   downside cost of potentially adding stretch to the connections of
   non-LISP sites trying to reach communicating with the LISP site.

7.  The third option is
   Proxy-ETRs, which are optionally used by sites relying on PITRs case
   to mitigate two caveats for LISP sites communicating with non-LISP
   sites.  This means Proxy-ETRs are not expected to be deployed by
   themselves, they will always be used to assist sites already using
   PITRs.

8.1.  How Proxy-ITRs and Proxy-ETRs Interact

   There is a subtle difference between Symmetrical (LISP-NAT) vs
   Asymmetrical (Proxy-ITR and Proxy-ETR) Interworking techniques.
   Operationally, Proxy-ITRs (PITRs) and Proxy-ETRs (PETRs) can (and
   likely should) be decoupled since Proxy-ITRs are best deployed
   closest to non-LISP sites, and Proxy-ETRs are best located close to
   the LISP site's they are decapsulating on behalf of.  This asymmetric
   placement of the two network elements keeps the stretched imposed on
   the connection to a minimum, while still allowing for coarsely
   aggregated announcements of EIDs into the Internet's routing table.

9.  Security Considerations

   Like any LISP ITR, PTRs PITRs will have the ability opportunity to inspect traffic
   at the time that they encapsulate.  More work needs to be done to see if
   this ability can be exploited by the control plane along  The location of these devices in
   the lines network can have implications for dropping malicious traffic on
   behalf of
   Remote Triggered BGP Black Holes.  XXX:Reference? ETRs who request this behavior (via the drop action bit in
   Map-Reply packets for an EID or EID prefix).

   As with traditional NAT, LISP-NAT will hide obscure the actual host ID
   LISP-NR EID behind the RLOCs LISP-R addresses used as the NAT pool.

   When LISP Sites reply send packets to non-LISP sites and (these non-LISP rely
   on PTRs PITRs to enable
   Interworking, Interworking), packets will be sourced from addresses have the Site's EID as
   its source IP address.  These EIDs may not be recognized by their
   Internet Service Provider's Unicast Reverse Path Forwarding (uRPF)
   rules enabled on the Provider Edge Router.  Several options are
   available to the service provider.  For example they could enable a
   less strict version of uRPF, where they only look for the existence
   of the the EID prefix in the routing table.  Another, more secure,
   option is to add a static route for the customer on the PE router,
   but not redistribute this route into the provider's routing table.

8.
   Finally, Proxy-ETRs can enable LISP sites to bypass this uRPF check
   by encapsulating all of their egressing traffic destined to non-LISP
   sites to the Proxy-ETR (thus ensuring the outer IP source address is
   the site's RLOC).

10.  Acknowledgments

   Thanks goes to Christian Vogt, Lixia Zhang and Zhang, Robin Whittle Whittle, Michael
   Menth, and Xuewei Wang who have made insightful comments with respect
   to interworking LISP Interworking and transition mechanisms.

   A special thanks goes to Scott Brim for his initial brainstorming of
   these ideas and also for his careful review.

9.

11.  IANA Considerations

   This document creates no new requirements on IANA namespaces
   [RFC2434].

10.

12.  References

10.1.

12.1.  Normative References

   [LISP]     Farinacci, D., Fuller, V., Oran, Meyer, D., and D. Meyer, Lewis,
              "Locator/ID Separation Protocol (LISP)",
              draft-ietf-lisp-00
              draft-ietf-lisp-06 (work in progress), May 2009. January 2010.

   [LISP-ALT]
              Farinacci, D., Fuller, V., Meyer, D., and D. Meyer, Lewis, "LISP
              Alternative Topology (LISP-ALT)", draft-ietf-lisp-alt-00
              draft-ietf-lisp-alt-02.txt (work in progress), May 2009.
              January 2010.

   [RFC1918]  Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
              E. Lear, "Address Allocation for Private Internets",
              BCP 5, RFC 1918, February 1996.

   [RFC4632]  Fuller, V. and T. Li, "Classless Inter-domain Routing
              (CIDR): The Internet Address Assignment and Aggregation
              Plan", BCP 122, RFC 4632, August 2006.

10.2.

12.2.  Informative References

   [CRIO]     Zhang, X., Francis, P., Wang, J., and K. Yoshida, "CRIO:
              Scaling IP Routing with the Core Router-Integrated
              Overlay".

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 2434,
              October 1998.

   [RFC2993]  Hain, T., "Architectural Implications of NAT", RFC 2993,
              November 2000.

Authors' Addresses

   Darrel Lewis
   Cisco Systems, Inc.

   Email: darlewis@cisco.com

   David Meyer
   Cisco Systems, Inc.

   Email: dmm@cisco.com

   Dino Farinacci
   Cisco Systems, Inc.

   Email: dino@cisco.com

   Vince Fuller
   Cisco Systems, Inc.

   Email: vaf@cisco.com
--Apple-Mail-8--45498354 Content-Disposition: attachment; filename=draft-ietf-lisp-interworking-01.txt Content-Type: text/plain; name="draft-ietf-lisp-interworking-01.txt" Content-Transfer-Encoding: quoted-printable Network Working Group D. Lewis Internet-Draft D. Meyer Intended status: Experimental D. Farinacci Expires: August 17, 2010 V. Fuller Cisco Systems, Inc. February 13, 2010 Interworking LISP with IPv4 and IPv6 draft-ietf-lisp-interworking-01.txt Abstract This document describes techniques for allowing sites running the Locator/ID Separation Protocol (LISP [LISP]) to interoperate with Internet sites (using either IPv4, IPv6, or both) which are not running LISP. A fundamental property of LISP speaking sites is that they use Endpoint Identifiers (EIDs), rather than traditional IP addresses, in the source and destination fields of all traffic they emit or receive. While EIDs are syntactically identical to IPv4 or IPv6 addresses, routes for them are not carried in the global routing system so an interoperability mechanism is needed for non-LISP- speaking sites to exchange traffic with LISP-speaking sites. This document introduces three such mechanisms: the first uses a new network element, the LISP Proxy Ingress Tunnel Routers (PITR) (Section 5) to act as a intermediate LISP Ingress Tunnel Router (ITR) for non-LISP-speaking hosts while the second adds Network Address Translation (NAT) functionality to LISP Ingress and LISP Egress Tunnel Routers (xTRs) to substitute routable IP addresses for non- routable EIDs. Finally, this document introduces a Proxy Egress Tunnel Router (PETR) to solve cases where a LISP site cannot send a packet which has as its source address a non-routable EID Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." Lewis, et al. Expires August 17, 2010 [Page 1] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 17, 2010. Copyright Notice Copyright (c) 2010 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 BSD License. Lewis, et al. Expires August 17, 2010 [Page 2] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. LISP Interworking Models . . . . . . . . . . . . . . . . . . . 6 3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 8 4. Routable EIDs . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1. Impact on Routing Table . . . . . . . . . . . . . . . . . 11 4.2. Requirement for using BGP . . . . . . . . . . . . . . . . 11 4.3. Limiting the Impact of Routable EIDs . . . . . . . . . . . 11 4.4. Use of Routable EIDs for Testing LISP . . . . . . . . . . 11 5. Proxy Ingress Tunnel Routers . . . . . . . . . . . . . . . . . 13 5.1. PITR EID announcements . . . . . . . . . . . . . . . . . . 13 5.2. Packet Flow with PITRs . . . . . . . . . . . . . . . . . . 13 5.3. Scaling PITRs . . . . . . . . . . . . . . . . . . . . . . 14 5.4. Impact of the PITRs placement in the network . . . . . . . 15 5.5. Benefit to Networks Deploying PITRs . . . . . . . . . . . 15 6. LISP-NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6.1. LISP-NAT for LISP-NR addressed hosts . . . . . . . . . . . 16 6.2. LISP Sites with Hosts using RFC 1918 Addresses Sending to non-LISP Sites . . . . . . . . . . . . . . . . . . . . 17 6.3. LISP Sites with Hosts using RFC 1918 Addresses Communicating to Other LISP Sites . . . . . . . . . . . . 17 6.4. LISP-NAT and multiple EIDs . . . . . . . . . . . . . . . . 18 6.5. When LISP-NAT and PITRs used by the same LISP Site . . . . 18 7. Proxy Egress Tunnel Routers . . . . . . . . . . . . . . . . . 20 7.1. Packet Flow with Proxy Egress Tunnel Routers . . . . . . . 20 8. Discussion of Proxy ITRs (PITRs), LISP-NAT, and Proxy-ETRs (PETRs) . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 8.1. How Proxy-ITRs and Proxy-ETRs Interact . . . . . . . . . . 22 9. Security Considerations . . . . . . . . . . . . . . . . . . . 23 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26 12.1. Normative References . . . . . . . . . . . . . . . . . . . 26 12.2. Informative References . . . . . . . . . . . . . . . . . . 26 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 27 Lewis, et al. Expires August 17, 2010 [Page 3] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 1. Introduction This document describes two mechanisms for interoperation between LISP [LISP] sites, which use non-globally-routed EIDs, and non-LISP sites: use of PITRs, which create highly-aggregated routes to EID prefixes for non-LISP sites to follow. The use of NAT by LISP ETRs when communicating with non-LISP hosts. And finally the use of Proxy Egress Tunnel routers (PETRs) LISP for sites relying on PITRs and which are faced with certain restrictions. A key behavior of the separation of Locators and End-Point-IDs is that EID prefixes are not advertised to the Internet's Default Free Zone (DFZ). Specifically, only RLOCs are carried in the Internet's DFZ. Existing Internet sites (and their hosts) who do not participate in the LISP system must still be able to reach sites numbered from this non routed EID space. This draft describes a set of mechanisms that can be used to provide reachability between sites that are LISP-capable and those that are not. This document introduces three such mechanisms. The first uses a new network element, the LISP Proxy Ingress Tunnel Router (PITR) (Section 5) to act as a intermediate LISP Ingress Tunnel Router (ITR) for non-LISP- speaking hosts. The second adds a form of Network Address Translation (NAT) functionality to Tunnel Routers (xTRs) to substitute routable IP addresses for non-routable EIDs. The final network element is the LISP Proxy Egress Tunnel Routers (PETR), which act as an intermediate Egress Tunnel Router (ETR) for LISP sites who are using PITRs but need assistance in reaching non-LISP sites. More detailed descriptions of these mechanisms and the network elements involved may be found in the following sections: - Section 2 describes the different cases where interworking mechanisms are needed - Section 3 defines terms used throughout the document - Section 4 describes the relationship between the new EID prefix space and the IP address space used by the current Internet - Section 5 introduces and describes the operation of Proxy-ITRs - Section 6 defines how NAT is used by ETRs to translate non-routable EIDs into routable IP addresses. - Section 7 introduces and describes the operations of Proxy-ETRs - Section 8 describes the relationship between asymmetric and Symmetric interworking mechanisms (Proxy-ITRs and Proxy-ETRs vs LISP- Lewis, et al. Expires August 17, 2010 [Page 4] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 NAT) Note that any successful interworking model should be independent of any particular EID-to-RLOC mapping algorithm. This document does not comment on the value of any of the particular LISP mapping systems. Lewis, et al. Expires August 17, 2010 [Page 5] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 2. LISP Interworking Models There are 4 unicast connectivity cases which describe how sites can communicate with each other: 1. Non-LISP site to Non-LISP site 2. LISP site to LISP site 3. LISP site to Non-LISP site 4. Non-LISP site to LISP site Note that while Cases 3 and 4 seem similar, there are subtle differences due to the way communications are originated. The first case is the Internet as we know it today and as such will not be discussed further here. The second case is documented in [LISP] and, hence, there are no new interworking requirements because there are no new protocol requirements placed on intermediate non- LISP routers. In case 3, LISP site to Non-LISP site, a LISP site can (in most cases) send packets to a non-LISP site because the non-LISP site prefixes are routable. The non-LISP site need not do anything new to receive packets. The only action the LISP site needs (with two possible caveats introduced below) to take is to know when not to LISP-encapsulate packets. This can be achieved via two mechanisms: 1. At the ITR in the source site, if the destination of an IP packet is found to match a prefix from the BGP routing table, then the site is directly reachable by the BGP core that exists and operates today. 2. Second, if (from the perspective of the ITR at the source site) the destination address of an IP address is not found in the EID- to-RLOC mapping database, the ITR could infer that it is not a LISP-capable site, and decide to not LISP-encapsulate the packet. 3. There are two potential caveats involved with Case 3, where there could be some situations where (unencapsualted) packets originated by a LISP site may not be forwarded to a non-LISP site. One of these caveats (uRPF check failure) are detailed in Section 9 (Security Considerations). The second caveat (protocol traversal) is reviewed in section 7, (Proxy-Egress Tunnel Routers). Case 4, typically the most challenging, occurs when a host at a non- Lewis, et al. Expires August 17, 2010 [Page 6] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 LISP site wishes to send traffic to a host at a LISP site. If the source host uses a (non-globally-routable) EID as the destination IP address, the packet is forwarded inside the source site until it reaches a router which cannot forward it, at which point the traffic is dropped. For traffic not to be dropped, either some route must be exist for the destination EID outside of LISP-speaking part of the network or an alternate mechanism must be in place. Section 5 (PITRs) and Section 6 (LISP-NAT) describe two such mechanisms. Note that case 4 includes packets returning to the LISP Site in case 3. Lewis, et al. Expires August 17, 2010 [Page 7] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 3. Definition of Terms Endpoint ID (EID): Endpoint ID (EID): A 32-bit (for IPv4) or 128-bit (for IPv6) value used in the source and destination address fields of the first (most inner) LISP header of a packet. The host obtains a destination EID the same way it obtains an destination address today, for example through a DNS lookup or SIP exchange. The source EID is obtained via existing mechanisms used to set a host's "local" IP address. An EID is allocated to a host from an EID-prefix block associated with the site where the host is located. An EID can be used by a host to refer to other hosts. EIDs MUST NOT be used as LISP RLOCs. Note that EID blocks may be assigned in a hierarchical manner, independent of the network topology, to facilitate scaling of the mapping database. In addition, an EID block assigned to a site may have site-local structure (subnetting) for routing within the site; this structure is not visible to the global routing system. When used in discussions with other Locator/ID separation proposals, a LISP EID will be called a "LEID". Throughout this document, any references to "EID" refers to an LEID. EID-Prefix: EID-prefix: A power-of-2 block of EIDs which are allocated to a site by an address allocation authority. EID- prefixes are associated with a set of RLOC addresses which make up a "database mapping". EID-prefix allocations can be broken up into smaller blocks when an RLOC set is to be associated with the smaller EID- prefix. A globally routed address block (whether PI or PA) is not an EID-prefix. However, a globally routed address block may be removed from global routing and reused as an EID- prefix. A site that receives an explicitly allocated EID-prefix may not use that EID-prefix as a globally routed prefix assigned to RLOCs EID-Prefix Aggregate: A set of EID-prefixes said to be aggregatable in the [RFC4632] sense. That is, an EID-Prefix aggregate is defined to be a single contiguous power-of-two EID-prefix block. Such a block is characterized by a prefix and a length. Provider Independent (PI) Addresses: an address block assigned from a pool where blocks are not associated with any particular location in the network (e.g. from a particular service provider), and is therefore not topologically aggregatable in the routing system. Routing Locator (RLOC): The IPv4 or IPv6 address of an egress tunnel router (ETR). It is the output of a EID-to-RLOC mapping lookup. An EID maps to one or more RLOCs. Typically, RLOCs are numbered from topologically-aggregatable blocks that are assigned to a site at each point to which it attaches to the global Internet; where the topology is defined by the connectivity of provider networks, Lewis, et al. Expires August 17, 2010 [Page 8] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 RLOCs can be thought of as PA addresses. Multiple RLOCs can be assigned to the same ETR device or to multiple ETR devices at a site. EID-to-RLOC Mapping: A binding between an EID and the RLOC-set that can be used to reach the EID. We use the term "mapping" in this document to refer to a EID-to-RLOC mapping. EID Prefix Reachability: An EID prefix is said to be "reachable" if one or more of its locators are reachable. That is, an EID prefix is reachable if the ETR (or its proxy) is reachable. Default Mapping: A Default Mapping is a mapping entry for EID-prefix 0.0.0.0/0. It maps to a locator-set used for all EIDs in the Internet. If there is a more specific EID-prefix in the mapping cache it overrides the Default Mapping entry. The Default Mapping route can be learned by configuration or from a Map-Reply message [LISP]. LISP Routable (LISP-R) Site: A LISP site whose addresses are used as both globally routable IP addresses and LISP EIDs. LISP Non-Routable (LISP-NR) Site: A LISP site whose addresses are EIDs only, these EIDs are not found in the legacy Internet routing table. LISP Proxy Ingress Tunnel Router (PITR): PITRs are used to provide interconnectivity between sites which use LISP EIDs and those which do not. They act as a gateway between the Legacy Internet and the LISP enabled Network. A given PITR advertises one or more highly aggregated EID prefixes into the public Internet and acts as the ITR for traffic received from the public Internet. LISP Proxy Ingress Tunnel Routers are described in Section 5. LISP Network Address Translation (LISP-NAT): Network Address Translation between EID space assigned to a site and RLOC space also assigned to that site. LISP Network Address Translation is described in Section 6. LISP Proxy Egress Tunnel Router (PETR): PETRs are used to provide a LISP site's ITRs the ability to send traffic to non-LISP sites in cases where unencapsualted packets (the default mechanism) would fail to be delivered. PETRs are implemented by having an ITR encapsulate all non-LISP destined traffic to a pre-configured PETR. LISP Proxy Egress Tunnel Routers are described in Section 7. Lewis, et al. Expires August 17, 2010 [Page 9] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 EID Sub Namespace: A power-of-two block of aggregatable locators set aside for LISP interworking. Lewis, et al. Expires August 17, 2010 [Page 10] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 4. Routable EIDs An obvious way to achieve interworking between LISP and non-LISP hosts is to simply announce EID prefixes into the DFZ, much like routing system, effectively treating them as "Provider Independent (PI)" prefixes. Doing this is undesirable as it defeats one of the primary goals of LISP - to reduce global routing system state. 4.1. Impact on Routing Table If EID prefixes are announced into the DFZ, the impact is similar to the case in which LISP has not been deployed, because these EID prefixes will be no more aggregatable than existing PI addressing. This behavior is not desirable and such a mechanism is not viewed as a viable long term solution. 4.2. Requirement for using BGP Non-LISP sites today use BGP to, among other things, enable ingress traffic engineering. Relaxing this requirement is another primary design goal of LISP. 4.3. Limiting the Impact of Routable EIDs Two schemes are proposed to limit the impact of having EIDs announced in the current global Internet routing table: 1. Section 5 discusses the LISP Proxy Tunnel Router, an approach that provides ITR functionality to bridge LISP-capable and non- LISP-capable sites. 2. Section 6 discusses another approach, LISP-NAT, in which NAT [RFC2993] is combined with ITR functionality to limit the the impact of routable EIDs on the Internet routing infrastructure. 4.4. Use of Routable EIDs for Testing LISP A primary design goal for LISP (and other Locator/ID separation proposals) is to facilitate topological aggregation of addresses and, thus, decrease global routing system state. Another goal is to achieve the benefits of improved aggregation as soon as possible. Sites advertising routes for LISP EID prefixes into the global routing system is therefore not recommended. That being said, single homed sites (or multi-homed sites that are not leaking more specific exceptions) and that are already using provider-aggregated prefixes can use these prefixes as LISP EIDs without adding state to the routing system; in other words, such Lewis, et al. Expires August 17, 2010 [Page 11] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 sites do not cause additional prefixes to be advertised. For such sites, connectivity to a non-LISP sites does not require interworking machinery because the "PA" EIDs are already routable (they are effectively LISP-R type sites). Their EIDs are found in the LISP mapping system, and their (aggregate) PA prefix(es) are found in the DFZ Internet. The continued announcements of an existing site's Provider Independent (or "PI") prefix(s) is of course under control of that site, and some period of transition where a site is is found both in the LISP mapping system and as a discrete prefix in the Internet routing system may be a viable transition strategy. Care should be taken not to advertise additional more specific LISP EID prefixes into the DFZ. Lewis, et al. Expires August 17, 2010 [Page 12] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 5. Proxy Ingress Tunnel Routers Proxy Ingress Tunnel Routers (PITRs) allow for non-LISP sites to communicate with LISP-NR sites. A PITR is a new network element that shares many characteristics with the LISP ITR. PITRs allow non-LISP sites to send packets to LISP-NR sites without any changes to protocols or equipment at the non-LISP site. PITRs have two primary functions: Originating EID Advertisements: PITRs advertise highly aggregated EID-prefix space on behalf of LISP sites to so that non-LISP sites can reach them. Encapsulating Legacy Internet Traffic: PITRs also encapsulate non- LISP Internet traffic into LISP packets and route them towards their destination RLOCs. 5.1. PITR EID announcements A key part of PITR functionality is to advertise routes for highly- aggregated EID prefixes into part of the global routing system. Aggressive aggregation is performed to minimize the number of new announced routes. In addition, careful placement of PITRs can greatly reduce the scope of these new routes. To this end, PITRs should be deployed close to non-LISP-speaking rather than close to LISP sites. Such deployment not only limits the scope of EID-prefix route advertisements, it also also allows traffic forwarding load to be spread among many PITRs. 5.2. Packet Flow with PITRs Packets from a non-LISP site can reach a LISP-NR site with the aid of a PITR. By advertising a route for a particular EID prefix into the global routing system, traffic destined for that EID prefix is routed to the PITR, which then performs LISP encapsulation. Once encapsulated, traffic packets use the LISP (outer) header's destination address to reach the destination ETR. What follows is an example of the path a packet would take when using a PITR. In this example, the LISP-NR site is given the EID prefix 240.0.0.0/24. For the purposes of this example, this prefix and no covering aggregate is present in the global routing system. In other words, if a packet with this destination were to reach a router in the "Default Free Zone", it would be dropped. A full protocol exchange example follows: Lewis, et al. Expires August 17, 2010 [Page 13] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 1. Source host makes a DNS lookup EID for destination, and gets 240.1.1.1 in return. 2. Source host has a default route to customer Edge (CE) router and forwards the packet to the CE. 3. The CE has a default route to its Provider Edge (PE) router, and forwards the packet to the PE. 4. The PE has route to 240.0.0.0/24 and the next hop is the PITR. 5. The PITR has or acquires a mapping for 240.1.1.1 and LISP encapsulates, the packet now has a destination address of the RLOC. The source address of this encapsulated packet is the PITR's RLOC. 6. The PITR looks up the RLOC, and forwards LISP packet to the next hop. 7. The ETR decapsulates the packet and delivers the packet to the 240.1.1.1 host in the destination LISP site. 8. Packets from host 240.1.1.1 will flow back through the LISP site's ITR. Such packets are not encapsulated because the ITR knows that the destination (the original source) is a non-LISP site. The ITR knows this because it can check the LISP mapping database for the destination EID, and on a failure determine that the destination site is not LISP enabled. 9. Packets are then routed natively and directly to the destination (original source) site. Note that in this example the return path is asymmetric, so return traffic will not go back through the PITR. This is because the LISP-NR site's ITR will discover that the originating site is not a LISP site, and not encapsulate the returning packet (see [LISP] for details of ITR behavior). The asymmetric nature of traffic flows allows the PITR to be relatively simple - it will only have to encapsulate LISP packets. 5.3. Scaling PITRs PITRs attract traffic by announcing the LISP EID namespace into parts of the non-LISP-speaking global routing system. There are several ways that a network could control how traffic reaches a particular PITR to prevent it from receiving more traffic than it can handle: Lewis, et al. Expires August 17, 2010 [Page 14] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 First, the PITR's aggregate routes might be selectively announced, giving a coarse way to control the quantity of traffic attracted by that PITR. Second, the same address might be announced by multiple PITRs in order to share the traffic using IP Anycast. The asymmetric nature of traffic flows allows the PITR to be relatively simple - it will only have to encapsulate LISP packets. 5.4. Impact of the PITRs placement in the network There are several approaches that a network could take in placing PITRs. Placing the PITR near the ingress of traffic allows for the communication between the non-LISP site and the LISP site to have the least "stretch" (i.e. the least number of forwarding hops when compared to an optimal path between the sites). Some proposals, for example CRIO [CRIO], have suggested grouping PITRs near an arbitrary subset of ETRs and announcing a 'local' subset of EID space. This model cannot guarantee minimum stretch if the EID prefix route advertisement points are changed (such a change might occur if a site adds, removes, or replaces one or more ISPs connections). 5.5. Benefit to Networks Deploying PITRs When traffic destined for LISP-NR site arrives and is encapsulated at a PITR, a new LISP packet header is pre-pended. This causes the packet's destination to be set to the destination site RLOC. Because traffic is thus routed towards RLOCs, it can potentially better follow the network's traffic engineering policies (such as closest exit routing). This also means that providers who are not default- free and do not deploy PITRs end up sending more traffic to expensive transit links rather than to RLOC addresses, to which they may have settlement-free peering. For large transit providers, deploying PITRs may attract more traffic, and therefore more revenue, from their customers. Lewis, et al. Expires August 17, 2010 [Page 15] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 6. LISP-NAT LISP Network Address Translation (LISP-NAT) is a limited form of NAT [RFC2993]. LISP-NAT is designed to enable the interworking of non- LISP sites and LISP-NR sites by ensuring that the LISP-NR's site addresses are always routable. LISP-NAT accomplishes this by translating a host's source address from an 'inner' value to an 'outer' value and keeping this translation in a table that it can reference for subsequent packets. In addition, existing RFC 1918 [RFC1918] sites can use LISP-NAT to talk to both LISP or non-LISP sites. The basic concept of LISP-NAT is that when transmitting a packet, the ITR replaces a non-routable EID source address with a routable source address, which enables packets to return to the site. There are two main cases that involve LISP-NAT: 1. Hosts at LISP sites that use non-routable global EIDs speaking to non-LISP sites using global addresses. 2. Hosts at LISP sites that use RFC 1918 private EIDs speaking to other sites, who may be either LISP or non-LISP. Note that LISP-NAT is not needed in the case of LISP-R (routable global EIDs) sources. This case occurs when a site is announcing its prefix into both the LISP mapping system as well as the Internet DFZ. This is because the LISP-R source's address is routable, and return packets will be able to natively reach the site. 6.1. LISP-NAT for LISP-NR addressed hosts LISP-NAT allows a host with a LISP-NR EID to communicate with non- LISP hosts by translating the LISP-NR EID to a globally unique address. This globally unique address may be a either a PI or PA address. An example of this translation follows. For this example, a site has been assigned a LISP-NR EID of 220.1.1.0/24. In order to utilize LISP-NAT, the site has also been provided the PA EID of 128.200.1.0/24, and uses the first address (128.200.1.1) as the site's RLOC. The rest of this PA space (128.200.1.2 to 128.200.1.254) is used as a translation pool for this site's hosts who need to communicate with non-LISP hosts. The translation table might look like the following: Lewis, et al. Expires August 17, 2010 [Page 16] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 Site NR-EID Site R-EID Site's RLOC Translation Pool =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 220.1.1.0/24 128.200.1.0/24 128.200.1.1 128.200.1.2-254 Figure 1: Example Translation Table The Host 220.1.1.2 sends a packet destined for a non-LISP site to its default route (the ITR). The ITR receives the packet, and determines that the destination is not a LISP site. How the ITR makes this determination is up to the ITRs implementation of the EID-to-RLOC mapping system used (see, for example [LISP-ALT]). The ITR then rewrites the source address of the packet from 220.1.1.2 to 128.200.1.2, which is the first available address in the LISP-R EID space available to it. The ITR keeps this translation in a table in order to reverse this process when receiving packets destined to 128.200.1.2. Finally, when the ITR forwards this packet without encapsulating it, it uses the entry in its LISP-NAT table to translate the returning packets' destination IPs to the proper host. 6.2. LISP Sites with Hosts using RFC 1918 Addresses Sending to non-LISP Sites In the case where RFC 1918 addressed hosts desire to communicate with non-LISP hosts the LISP-NAT implementation acts much like an existing IPv4 NAT device. The ITR providing the NAT service must use LISP-R EIDs for its global pool as well as providing all the standard NAT functions required today. The source of the packet must be translated to a LISP-R EID in a manner similar to Section 6, and this packet must be forwarded to the ITR's next hop for the destination, without LISP encapsulation. 6.3. LISP Sites with Hosts using RFC 1918 Addresses Communicating to Other LISP Sites LISP-NAT allows a host with a RFC 1918 address to communicate with LISP hosts by translating the RFC 1918 address to a LISP EID. After translation, the communication between source and destination ITR and ETRs continues as described in [LISP]. An example of this translation and encapsulation follows. For this example, a host has been assigned a RFC 1918 address of 192.168.1.2. In order to utilize LISP-NAT, the site also has been provided the LISP-R EID of 192.0.2.0/24, and uses the first address (192.0.2.1) as the site's RLOC. The rest of this PA space (192.0.2.2 to Lewis, et al. Expires August 17, 2010 [Page 17] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 192.0.2.254) is used as a translation pool for this site's hosts who need to communicate with both non-LISP and LISP hosts. The Host 192.168.1.2 sends a packet destined for a non-LISP site to its default route (the ITR). The ITR receives the packet and determines that the destination is a LISP site. How the ITR makes this determination is up to the ITRs implementation of the EID/RLOC mapping system. The ITR then rewrites the source address of the packet from 192.168.1.2 to 192.0.2.2, which is the first available address in the LISP EID space available to it. The ITR keeps this translation in a table in order to reverse this process when receiving packets destined to 192.0.2.2. The ITR then LISP encapsulates this packet (see [LISP] for details). The ITR uses the site's RLOC as the LISP outer header's source and the translation address as the LISP inner header's source. Once it decapsulates returning traffic, it uses the entry in its LISP-NAT table to translate the returning packet's destination IP address and then forward to the proper host. 6.4. LISP-NAT and multiple EIDs When a site has two addresses that a host might use for global reachability, care must be chosen on which EID is found in DNS. For example, whether applications such as DNS use the LISP-R EID or the LISP-NR EID. This problem exists for NAT in general, but the specific issue described above is unique to LISP. Using PITRs can mitigate this problem, since the LISP-NR EID can be reached in all cases. 6.5. When LISP-NAT and PITRs used by the same LISP Site With LISP-NAT, there are two EIDs possible for a given host, the LISP-R EID and the LISP-NR EID. When a site has two addresses that a host might use for global reachability, name-to-address directories may need to be modified. This problem, global addressability, exists for NAT in general, but the specific issue described above is unique to LOC/ID split schemes. Some schemes [ref: 6-1 proxy] have suggested running a separate DNS instance for legacy types of EIDs. This solves the problem but introduces complexity for the site. Alternatively, using PITRs can mitigate this problem, because the LISP-NR EID can be reached in all cases. In summary, there are two options for interworking LISP with IPv4 and Lewis, et al. Expires August 17, 2010 [Page 18] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 V6. In the NAT case the LISP site can use NAT and manage the transition on its own. In the PITR case, we add a new network element called a PITR that can relieve that burden on the site, with the downside of potentially adding stretch to sites trying to reach the LISP site. Lewis, et al. Expires August 17, 2010 [Page 19] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 7. Proxy Egress Tunnel Routers Proxy Egress Tunnel Routers (PETRs) allow for LISP-NR sites to communicate with non-LISP sites in the case where the access network does not allow for the LISP-NR site send packets with the source address of the site's EID(s). A PETR is a new network element that conceptually acts as an ETR for traffic destined to non-LISP sites. This also has the effect of allowing an ITR avoid having to decide whether to encapsulate packets or not - it will always encapsulate packets. Packets destined to LISP sites will travel directly to that site's ETR, all other packets will be sent to the site's PETR. There are two primary reasons why sites would want to utilize a PETR: Avoiding strict uRPF failures: Some provider's access networks require the source of the packets emitted to be within the addressing scope of the access networks. (see section 9) Traversing a different IP Protocol: A LISP site may want to transmit packets to a non-LISP site where the some of the intermediate network does not support an IP protocol (v4 or v6). PETRs can allow this LISP site's data to 'hop over' this by utilizing LISP's support for mixed protocol encapsulation. 7.1. Packet Flow with Proxy Egress Tunnel Routers Packets from a LISP site can reach a non-LISP site with the aid of a Proxy-ETR (or PETR). An ITR is simply configured to send all non- LISP traffic, which it normally would have forwarded natively (non- encapsulated), to a PETR. Note that this outer encapsulation may be in another IP protocol than the (inner) encapsulated data. Traffic then uses use the LISP (outer) header's destination address to reach the destination PETR. A PETR should verify the (inner) source EID of the packet at time of decapsulation in order to verify that this is from a configured LISP site. This is to prevent spoofed inner sources from being encapsulated through the Proxy-ETR. What follows is an example of the path a packet would take when using a PETR. In this example, the LISP-NR site is given the EID prefix 240.2.0.0/24, and it is trying to reach host at a non-LISP site with the IP prefix of 192.0.2.0/24. For the purposes of this example, the destination is a non-LISP site and 192.0.2.0/24 is found in the Internet's routing system. A full protocol exchange example follows: Lewis, et al. Expires August 17, 2010 [Page 20] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 1. Source host makes a DNS lookup for the destination, and gets 192.0.2.100 (a non-LISP site) in return. 2. Source host has a default route to customer Edge (CE) router and forwards the packet towards the CE. 3. The CE is a LISP ITR, and is configured to encapsulate traffic destined for non-lisp sites to a Proxy-ETR. 4. The Proxy ETR decapsulates the LISP packet and forwards the original packet to its next hop. 5. The packet is then routed natively and directly to the destination (non-LISP) site 192.0.2.0/24. Note that in this example the return path is asymmetric, so return traffic will not go back through the Proxy-ITR. This means that in order to reach LISP-NR sites, non-lisp sites must still use Proxy ITRs. Lewis, et al. Expires August 17, 2010 [Page 21] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 8. Discussion of Proxy ITRs (PITRs), LISP-NAT, and Proxy-ETRs (PETRs) In summary, there are three options for interworking LISP with non- LISP Sites (for both IPv4 and IPv6). In the LISP-NAT option the LISP site can manage and control the interworking on its own. In the PITR case, we add a new network element relieve that burden on the site, with the cost of potentially adding stretch to the connections of non-LISP sites communicating with the LISP site. The third option is Proxy-ETRs, which are optionally used by sites relying on PITRs case to mitigate two caveats for LISP sites communicating with non-LISP sites. This means Proxy-ETRs are not expected to be deployed by themselves, they will always be used to assist sites already using PITRs. 8.1. How Proxy-ITRs and Proxy-ETRs Interact There is a subtle difference between Symmetrical (LISP-NAT) vs Asymmetrical (Proxy-ITR and Proxy-ETR) Interworking techniques. Operationally, Proxy-ITRs (PITRs) and Proxy-ETRs (PETRs) can (and likely should) be decoupled since Proxy-ITRs are best deployed closest to non-LISP sites, and Proxy-ETRs are best located close to the LISP site's they are decapsulating on behalf of. This asymmetric placement of the two network elements keeps the stretched imposed on the connection to a minimum, while still allowing for coarsely aggregated announcements of EIDs into the Internet's routing table. Lewis, et al. Expires August 17, 2010 [Page 22] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 9. Security Considerations Like any LISP ITR, PITRs will have the opportunity to inspect traffic at the time that they encapsulate. The location of these devices in the network can have implications for dropping malicious traffic on behalf of ETRs who request this behavior (via the drop action bit in Map-Reply packets for an EID or EID prefix). As with traditional NAT, LISP-NAT will obscure the actual host LISP-NR EID behind the LISP-R addresses used as the NAT pool. When LISP Sites send packets to non-LISP sites (these non-LISP rely on PITRs to enable Interworking), packets will have the Site's EID as its source IP address. These EIDs may not be recognized by their Internet Service Provider's Unicast Reverse Path Forwarding (uRPF) rules enabled on the Provider Edge Router. Several options are available to the service provider. For example they could enable a less strict version of uRPF, where they only look for the existence of the the EID prefix in the routing table. Another, more secure, option is to add a static route for the customer on the PE router, but not redistribute this route into the provider's routing table. Finally, Proxy-ETRs can enable LISP sites to bypass this uRPF check by encapsulating all of their egressing traffic destined to non-LISP sites to the Proxy-ETR (thus ensuring the outer IP source address is the site's RLOC). Lewis, et al. Expires August 17, 2010 [Page 23] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 10. Acknowledgments Thanks goes to Christian Vogt, Lixia Zhang, Robin Whittle, Michael Menth, and Xuewei Wang who have made insightful comments with respect to LISP Interworking and transition mechanisms. A special thanks goes to Scott Brim for his initial brainstorming of these ideas and also for his careful review. Lewis, et al. Expires August 17, 2010 [Page 24] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 11. IANA Considerations This document creates no new requirements on IANA namespaces [RFC2434]. Lewis, et al. Expires August 17, 2010 [Page 25] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 12. References 12.1. Normative References [LISP] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "Locator/ID Separation Protocol (LISP)", draft-ietf-lisp-06 (work in progress), January 2010. [LISP-ALT] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "LISP Alternative Topology (LISP-ALT)", draft-ietf-lisp-alt-02.txt (work in progress), January 2010. [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, February 1996. [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan", BCP 122, RFC 4632, August 2006. 12.2. Informative References [CRIO] Zhang, X., Francis, P., Wang, J., and K. Yoshida, "CRIO: Scaling IP Routing with the Core Router-Integrated Overlay". [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [RFC2993] Hain, T., "Architectural Implications of NAT", RFC 2993, November 2000. Lewis, et al. Expires August 17, 2010 [Page 26] =0C Internet-Draft Interworking LISP with IPv4 and IPv6 February 2010 Authors' Addresses Darrel Lewis Cisco Systems, Inc. Email: darlewis@cisco.com David Meyer Cisco Systems, Inc. Email: dmm@cisco.com Dino Farinacci Cisco Systems, Inc. Email: dino@cisco.com Vince Fuller Cisco Systems, Inc. Email: vaf@cisco.com Lewis, et al. Expires August 17, 2010 [Page 27] =0C --Apple-Mail-8--45498354 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii On Feb 12, 2010, at 3:16 PM, Darrel Lewis wrote: >=20 > Here is an updated version of the LISP Interworking specification that = I'd like to > publish to the Internet Drafts repository. >=20 > The main addition to the draft is a the introduction of an optional = network element called the "Proxy Egress Tunnel Router" or PETR. =20 >=20 > Both html diffs and the full text of the new draft are attached. >=20 > Comments appreciated. I'd like to get this posted next Friday (by > Feb 22nd). >=20 > -Darrel > (for the other Interworking authors: Dino, Dave, and Vince) >=20 > = _______________________________________________ > lisp mailing list > lisp@ietf.org > https://www.ietf.org/mailman/listinfo/lisp --Apple-Mail-8--45498354-- From terry.manderson@icann.org Wed Feb 17 15:40:20 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 6551B3A7E07 for ; Wed, 17 Feb 2010 15:40:20 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -5.67 X-Spam-Level: X-Spam-Status: No, score=-5.67 tagged_above=-999 required=5 tests=[AWL=-0.929, BAYES_20=-0.74, RCVD_IN_DNSWL_MED=-4] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kou6x-2Y8oVC for ; Wed, 17 Feb 2010 15:40:19 -0800 (PST) Received: from EXPFE100-2.exc.icann.org (expfe100-2.exc.icann.org [64.78.22.237]) by core3.amsl.com (Postfix) with ESMTP id BF70E3A7A70 for ; Wed, 17 Feb 2010 15:40:19 -0800 (PST) Received: from EXVPMBX100-1.exc.icann.org ([64.78.22.232]) by EXPFE100-2.exc.icann.org ([64.78.22.237]) with mapi; Wed, 17 Feb 2010 15:41:59 -0800 From: Terry Manderson To: "lisp@ietf.org" Date: Wed, 17 Feb 2010 15:42:00 -0800 Thread-Topic: LISP Secretary Thread-Index: AcqwKsyHa3HwvfyG7k27XzFD3YdLdQ== Message-ID: Accept-Language: en, en-US Content-Language: en X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en, en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: [lisp] LISP Secretary X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Feb 2010 23:40:20 -0000 Hi All, This is a quick note to introduce Wassim Haddad to the Working Group. Wassim has kindly volunteered to take on the LISP-WG secretary role. Wassim has been floating around the IETF since 2003 and has been involved i= n IPv6 mobility, IPv6 network access security (SeND), and v4/v6 transition. H= e has co-authored RFC4866 and is now editing the security threat model for 6lowpan WG and also co-authoring the "NEMO Prefix Delegation" draft which i= s in last call. Please welcome Wassim to the fold and assist him in any way you can. Cheers Terry From terry.manderson@icann.org Thu Feb 18 22:20:58 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 93A153A7721 for ; Thu, 18 Feb 2010 22:20:58 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -6.289 X-Spam-Level: X-Spam-Status: No, score=-6.289 tagged_above=-999 required=5 tests=[AWL=0.310, BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Py7M17TU2cfm for ; Thu, 18 Feb 2010 22:20:56 -0800 (PST) Received: from EXPFE100-1.exc.icann.org (expfe100-1.exc.icann.org [64.78.22.236]) by core3.amsl.com (Postfix) with ESMTP id 096633A7C6C for ; Thu, 18 Feb 2010 22:20:56 -0800 (PST) Received: from EXVPMBX100-1.exc.icann.org ([64.78.22.232]) by EXPFE100-1.exc.icann.org ([64.78.22.236]) with mapi; Thu, 18 Feb 2010 22:22:40 -0800 From: Terry Manderson To: "lisp@ietf.org" Date: Thu, 18 Feb 2010 22:22:40 -0800 Thread-Topic: Lisp Secretaries Thread-Index: AcqxK+/l6mLQhWNfSEGYB7ri2VbC9w== Message-ID: Accept-Language: en, en-US Content-Language: en X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en, en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: [lisp] Lisp Secretaries X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Feb 2010 06:20:58 -0000 Hi Folks, Joel and I have decided to take on two WG secretaries for LISP. Please welcome Luigi Iannone as our additional secretary. Many of you already know Luigi, so just to recap: Luigi started participating in the IETF and IRTF in 2007, mainly involved in the routing area WGs. He is actively working in the LISP WG and is one of the developers of OpenLISP, an open source LISP implementation. Please welcome Luigi to the collective and assist him in any way you can. We (Joel and I) are looking forward to working with both Luigi and Wassim. Cheers Terry From jmh@joelhalpern.com Fri Feb 19 06:30:41 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id F26E83A7CDD for ; Fri, 19 Feb 2010 06:30:40 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -3.484 X-Spam-Level: X-Spam-Status: No, score=-3.484 tagged_above=-999 required=5 tests=[AWL=0.115, BAYES_00=-2.599, RCVD_IN_DNSWL_LOW=-1] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id crduMBxUONKC for ; Fri, 19 Feb 2010 06:30:39 -0800 (PST) Received: from hermes.mail.tigertech.net (hermes.mail.tigertech.net [64.62.209.72]) by core3.amsl.com (Postfix) with ESMTP id 50F483A6A3D for ; Fri, 19 Feb 2010 06:30:39 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by hermes.tigertech.net (Postfix) with ESMTP id 6B73E430034 for ; Fri, 19 Feb 2010 06:32:26 -0800 (PST) X-Virus-Scanned: Debian amavisd-new at hermes.tigertech.net Received: from [10.10.10.102] (pool-71-161-51-31.clppva.btas.verizon.net [71.161.51.31]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by hermes.tigertech.net (Postfix) with ESMTPSA id C8B1F430032 for ; Fri, 19 Feb 2010 06:32:25 -0800 (PST) Message-ID: <4B7EA0F8.2070905@joelhalpern.com> Date: Fri, 19 Feb 2010 09:32:24 -0500 From: "Joel M. Halpern" User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: "lisp@ietf.org" Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [lisp] Interworking and Deployment documentation X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Feb 2010 14:30:41 -0000 There are a number of folks who are reviewing our documents, and trying to understand our work without the benefit of the WG context. This is very good, as the documents need to stand alone. These folks have raised a number of questions with me. After talking with Terry and Darrel about some of these issues, we would like to plan on resurrecting one of the documents that has been allowed to languish, to address part of this. Darrel had previously written a document on LISP Interworking. This will focus on the technical means that are needed to enable Interwoking between LISP and the large, non-upgraded, world. In addition it seems likely that we need a document that describes practical deployments for LISP. This would be similar to an applicability statement, but somewhat broader. What follows are some of the things I think could be in this document. But first, the questions. Do folks think we need a deployment document? Is anyone willing to work on or be the editor for such a document? Potential contents would seem to include: Placement of ITRs and ETRs (and who is responsible for managing them.) Structure for EID allocation. Placement and management of ALT routers, at the top of the hierarchy. Relationship between LISP EID delegation and ALT Router operations, including issues of ALT-Provider lockin. Placement and operation of PITRs (and incentives for same.) Placement and operation of PETRs. Placement and operation of MS/MR devices. Some of the items above may not be worth writing up. Some are probably very simple along the lines of "logical component X goes with logical component Y." But that list does seem to be a set of questions that will help folks understand how the system will work, and what problems it can or can not address. Yours, Joel M. Halpern From jnc@mercury.lcs.mit.edu Fri Feb 19 07:21:04 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id DEF5E3A711D for ; Fri, 19 Feb 2010 07:21:04 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -6.436 X-Spam-Level: X-Spam-Status: No, score=-6.436 tagged_above=-999 required=5 tests=[AWL=0.163, BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SXfAoIp62Rxh for ; Fri, 19 Feb 2010 07:21:03 -0800 (PST) Received: from mercury.lcs.mit.edu (mercury.lcs.mit.edu [18.26.0.122]) by core3.amsl.com (Postfix) with ESMTP id EAF3F3A769C for ; Fri, 19 Feb 2010 07:21:02 -0800 (PST) Received: by mercury.lcs.mit.edu (Postfix, from userid 11178) id 663F56BE5A5; Fri, 19 Feb 2010 10:22:47 -0500 (EST) To: lisp@ietf.org Message-Id: <20100219152247.663F56BE5A5@mercury.lcs.mit.edu> Date: Fri, 19 Feb 2010 10:22:47 -0500 (EST) From: jnc@mercury.lcs.mit.edu (Noel Chiappa) Cc: jnc@mercury.lcs.mit.edu Subject: Re: [lisp] Interworking and Deployment documentation X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Feb 2010 15:21:05 -0000 > From: "Joel M. Halpern" > it seems likely that we need a document that describes practical > deployments for LISP. > .. > Do folks think we need a deployment document? I think it would be very useful/nice to have such a document. As in, I don't think the effort will fail without it (as would be true with, for instance, the inter-working document you mentioned, where that capability is _critical_). On the other hand, I also agree that would be very useful to have such a document, because i) it will help outsiders understand all these aspects, and ii) more importantly, going through it all in detail might find some holes. On the gripping hand, we have a limited amount of manpower available, and the question is, would it be better to deploy that manpower to work on some of the outstanding technical issues (I have a long list of them here :-), or should we do this document instead? I guess it all comes down to 'do we have someone who will do it who isn't already fully used up working on other stuff' - which, providentially, was your next question! :-) > Is anyone willing to work on or be the editor for such a document? Not me, alas... Although anyone who does volunteer will have my deep gratitude! :-) > Potential contents would seem to include: > Placement of ITRs and ETRs (and who is responsible for managing them.) > Structure for EID allocation. Not sure there's a _lot_ to say there, but it's probably worth mentioning the topic. > Placement and management of ALT routers, at the top of the hierarchy. > Relationship between LISP EID delegation and ALT Router operations, > including issues of ALT-Provider lockin. > Placement and operation of PITRs (and incentives for same.) > Placement and operation of PETRs. > Placement and operation of MS/MR devices. Seems like a good list - I can't off the top of my head think of anything that's missing. {Ponders} How about how to configure LISP to do stuff like making best use of multi-homing, in particular configuring the RLOC list (with the weights and priorities)? Although fully exploring all the capabiltiies available with those mechanisms might be a document in itself (particularly when allied with source-specific mappings, and nested mappings)... And also use of LISP behind a NAT box - what are the current limitations, what kinds of NAT does it work with, etc. > Some of the items above may not be worth writing up. > Some are probably very simple If they are questions that people are asking, it is very worth writing up answers, even if the answers are simple. (Hey, that will makes the scribe's job that much easier... :-) > But that list does seem to be a set of questions that will help folks > understand how the system will work, and what problems it can or can not > address. That might be another section (or perhaps a separate document at some point): 'what LISP can/will and can't/won't do for you and the Internet as a whole'. Noel From job@instituut.net Fri Feb 19 09:04:22 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id A3A0828C169 for ; Fri, 19 Feb 2010 09:04:22 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: 1.602 X-Spam-Level: * X-Spam-Status: No, score=1.602 tagged_above=-999 required=5 tests=[AWL=2.039, BAYES_00=-2.599, FH_RELAY_NODNS=1.451, HELO_MISMATCH_NET=0.611, RDNS_NONE=0.1] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dgRSsTIFQ1Rl for ; Fri, 19 Feb 2010 09:04:20 -0800 (PST) Received: from masteen.6core.net (unknown [212.19.216.212]) by core3.amsl.com (Postfix) with ESMTP id 9FECD28C316 for ; Fri, 19 Feb 2010 09:03:54 -0800 (PST) Received: from [172.16.42.148] (252-119.citynet.ftth.internl.net [85.223.119.252]) by masteen.6core.net (Postfix) with ESMTPSA id 554A410808B4; Fri, 19 Feb 2010 18:07:12 +0100 (CET) Mime-Version: 1.0 (Apple Message framework v1077) Content-Type: text/plain; charset=us-ascii From: "Job W. J. Snijders" In-Reply-To: <20100219152247.663F56BE5A5@mercury.lcs.mit.edu> Date: Fri, 19 Feb 2010 18:05:40 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: <671B5749-8EB2-4F95-AEBB-176C34AF50CD@instituut.net> References: <20100219152247.663F56BE5A5@mercury.lcs.mit.edu> To: jnc@mercury.lcs.mit.edu (Noel Chiappa) X-Mailer: Apple Mail (2.1077) Cc: Gregg Schudel , lisp@ietf.org Subject: Re: [lisp] Interworking and Deployment documentation X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Feb 2010 17:04:22 -0000 Dear LISPers, I'm new to the list. I just recently got more actively involved with = LISP because Cisco put LISP (ipv4) support in IOS 15.1(1)XB ! :-) On 19 feb 2010, at 16:22, Noel Chiappa wrote: >> it seems likely that we need a document that describes practical >> deployments for LISP. >> .. >> Do folks think we need a deployment document? >=20 > I think it would be very useful/nice to have such a document. I agree! More guidance as to what lisp does, what the benefits are for = businesses, how it works, how it relates to the world as we know it = would be welcome.=20 Right now I am setting up a semi-production network in cooperation with = Gregg Schudel, David Meyer & the other Cisco guys.=20 >> Potential contents would seem to include: >> Placement of ITRs and ETRs (and who is responsible for managing = them.) >> Structure for EID allocation. >=20 > Not sure there's a _lot_ to say there, but it's probably worth = mentioning the > topic. I'm curious about the structure for EID allocation, how is it currently = done?=20 >> Placement and management of ALT routers, at the top of the hierarchy. >> Relationship between LISP EID delegation and ALT Router operations, >> including issues of ALT-Provider lockin. >> Placement and operation of PITRs (and incentives for same.) >> Placement and operation of PETRs. >> Placement and operation of MS/MR devices. >=20 > Seems like a good list - I can't off the top of my head think of = anything > that's missing. {Ponders} These are things I am going to deal with, and I would be more then happy = to share my progress on these topics as i struggle. I'm not entirely = sure what format the document should be and what information is useful, = so maybe I can hop along and help a more experienced editor with my = experiences?=20 My goals currently are: - get EID allocation from 153.16.0.0/16 and 2610:00D0::/32 for = some smaller sites and some larger sites - setup xTR routers at various places - connect to ALT - setup MS/MR - setup PITR/PETR routers in AS8283 and make additional globally = routable space available to 'the EID' for third (testing) parties. Through one of my employers: InTouch NV in Amsterdam (AS8283) i have = been generously provided with hardware and connectivity & some ipspace = to accomplish all of this. Some of you might remember InTouch for = accomodating one of the first ipv6 tunnel brokers in europe (now SIXXS) = and providing services to 6BONE.=20 I am completly new to trying to cooperate in a IETF WG, and I'm also = kind of a beginner when it comes to LISP, so please bear with me. :-) Kind regards, Job Snijders InTouch NV JWJS1-RIPE From jmh@joelhalpern.com Fri Feb 19 13:35:08 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 101023A7E0E for ; Fri, 19 Feb 2010 13:35:08 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -3.497 X-Spam-Level: X-Spam-Status: No, score=-3.497 tagged_above=-999 required=5 tests=[AWL=0.102, BAYES_00=-2.599, RCVD_IN_DNSWL_LOW=-1] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Xkk-btGl2JGE for ; Fri, 19 Feb 2010 13:35:05 -0800 (PST) Received: from hermes.mail.tigertech.net (hermes.mail.tigertech.net [64.62.209.72]) by core3.amsl.com (Postfix) with ESMTP id 268E73A7B77 for ; Fri, 19 Feb 2010 13:35:05 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by hermes.tigertech.net (Postfix) with ESMTP id 6E57C43B311 for ; Fri, 19 Feb 2010 13:36:53 -0800 (PST) X-Virus-Scanned: Debian amavisd-new at hermes.tigertech.net Received: from [10.10.10.102] (pool-71-161-51-31.clppva.btas.verizon.net [71.161.51.31]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by hermes.tigertech.net (Postfix) with ESMTPSA id EF3BE439FC8 for ; Fri, 19 Feb 2010 13:36:52 -0800 (PST) Message-ID: <4B7F0474.3070202@joelhalpern.com> Date: Fri, 19 Feb 2010 16:36:52 -0500 From: "Joel M. Halpern" User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: "lisp@ietf.org" Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [lisp] Scheduling X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Feb 2010 21:35:08 -0000 We have been tentatively given two slots. If you see an important conflict we overlooked, please let us know. (There are always some conflicts.) Thank you, Joel M. Halpern MONDAY, March 22, 2010 1300-1500 Afternoon Session I California B APP oauth Open Authentication Protocol WG California A INT 6lowpan IPv6 over Low power WPAN WG Huntington INT lisp Locator/ID Separation Protocol WG Manhattan OPS bmwg Benchmarking Methodology WG Palos Verdes RAI martini Multiple AoR reachabiliTy InformatioN Indication WG California D RTG ccamp Common Control and Measurement Plane WG Redondo SEC nea Network Endpoint Assessment WG WEDNESDAY, March 24, 2010 0900-1015 Morning Session I Manhattan APP vcarddav vCard and CardDAV WG Huntington INT ancp Access Node Control Protocol WG California B INT lisp Locator/ID Separation Protocol WG California A OPS opsawg Operations and Management Area Working Group WG Palos Verdes RAI drinks Data for Reachability of Inter/tra-NetworK SIP WG California C RTG sidr Secure Inter-Domain Routing WG Redondo SEC emu EAP Method Update WG California D TSV conex Congestion Exposure From vaf@cisco.com Mon Feb 22 14:31:34 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 46C6028C40F for ; Mon, 22 Feb 2010 14:31:34 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -8.332 X-Spam-Level: X-Spam-Status: No, score=-8.332 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, HTML_MESSAGE=0.001, J_CHICKENPOX_43=0.6, RCVD_IN_DNSWL_HI=-8, SARE_HTML_SINGLETS=1.666] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nHa2wqe4zbk8 for ; Mon, 22 Feb 2010 14:31:26 -0800 (PST) Received: from sj-iport-1.cisco.com (sj-iport-1.cisco.com [171.71.176.70]) by core3.amsl.com (Postfix) with ESMTP id 0953728C419 for ; Mon, 22 Feb 2010 14:31:26 -0800 (PST) Authentication-Results: sj-iport-1.cisco.com; dkim=neutral (message not signed) header.i=none X-Files: rfcdiff-alt-02-to-03.html, draft-ietf-lisp-alt-03.txt : 103715, 52752 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEACeVgkurR7Hu/2dsb2JhbACbAXOkZIpajUmCSgwDghIEgxWLRg X-IronPort-AV: E=Sophos;i="4.49,521,1262563200"; d="txt'?html'217?scan'217,208,217";a="301807795" Received: from sj-core-5.cisco.com ([171.71.177.238]) by sj-iport-1.cisco.com with ESMTP; 22 Feb 2010 22:33:25 +0000 Received: from vaf-lnx1 (vaf-lnx1.cisco.com [128.107.165.254]) by sj-core-5.cisco.com (8.13.8/8.14.3) with ESMTP id o1MMXPc6019925 for ; Mon, 22 Feb 2010 22:33:25 GMT Received: by vaf-lnx1 (Postfix, from userid 113818) id 6418320765; Mon, 22 Feb 2010 14:29:58 -0800 (PST) Date: Mon, 22 Feb 2010 14:29:58 -0800 From: Vince Fuller To: lisp@ietf.org Message-ID: <20100222222958.GB11758@vaf-lnx1.cisco.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="A6N2fC+uXW/VQSAv" Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Subject: [lisp] proposed draft-ietf-lisp-alt-03 draft X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Feb 2010 22:31:34 -0000 --A6N2fC+uXW/VQSAv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Here is a -03 version of the LISP+ALT specification. Changes are mostly editorial and for clarity. There are also now more dependencies on the Map-Server document, with emphasis that ITRs and ETRs generally use the Map-Server/Map-Resolver interface rather than connecting directly to the ALT. One significant clarification is how an aggregating ALT router (which may be a Map-Server) should handle reception of a Map-Request that matches a "hole" in an aggregate EID prefix it is originating. Both html diffs (from the -02 version) and the full text of the new draft are attached. Comments appreciated. I'd like to post this to the Internet-Drafts repository by the end of the business day (PST) on Monday, March 1st. --Vince (for the other ALT authors: Dino, Dave, and Darrel) --A6N2fC+uXW/VQSAv Content-Type: text/html; charset=us-ascii Content-Disposition: attachment; filename="rfcdiff-alt-02-to-03.html" wdiff draft-ietf-lisp-alt-02.txt draft-ietf-lisp-alt-03.txt 
Network Working Group                                          V. Fuller
Internet-Draft                                              D. Farinacci
Intended status: Experimental                                   D. Meyer
Expires: July 29, August 21, 2010                                        D. Lewis
                                                                   Cisco
                                                        January 25,
                                                       February 17, 2010

                  LISP Alternative Topology (LISP+ALT)
                       draft-ietf-lisp-alt-02.txt
                       draft-ietf-lisp-alt-03.txt

Abstract

   This document describes a method of building an alternative, logical
   topology for managing Alternative Logical
   Topology (ALT) to be used by the Locator/ID Separation Protocol
   (LISP) to find Endpoint Identifier (EID) to Routing Locator mappings
   using the Locator/ID Separation Protocol. (RLOC)
   mappings.  The logical network ALT is built as an overlay on the public Internet
   using existing technologies and tools, specifically the Border
   Gateway Protocol and the Generic Routing Encapsulation.  An important
   design goal for LISP+ALT is to allow for the relatively easy
   deployment of an
   efficient a mapping system while minimizing changes to existing
   hardware and software.

Status of this Memo

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

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

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on July 29, August 21, 2010.

Copyright Notice
   Copyright (c) 2010 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 BSD License.

Table of Contents

   1.  Requirements Notation  . . . . . . . . . . . . . . . . . . . .  4
   2.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Definition of Terms  . . . . . . . . . . . . . . . . . . . . .  6  7
   4.  The LISP 1.5 LISP+ALT model . . . . . . . . . . . . . . . . . . . . . .  8 10
     4.1.  Routeability of EIDs . . . . . . . . . . . . . . . . . . .  8 10
       4.1.1.  Mechanisms for an ETR to originate EID-prefixes  . . . 11
       4.1.2.  Mechanisms for an ITR to forward to EID-prefixes . . . 11
       4.1.3.  Map Server Model preferred . . . . . . . . . . . . . . 11
     4.2.  Connectivity to non-LISP sites . . . . . . . . . . . . . .  9 11
     4.3.  Caveats on the use of Data Probes  . . . . . . . . . . . .  9 12
   5.  LISP+ALT: Overview . . . . . . . . . . . . . . . . . . . . . . 10 13
     5.1.  ITR traffic handling . . . . . . . . . . . . . . . . . . . 11 14
     5.2.  EID Assignment - Hierarchy and Topology  . . . . . . . . . 11 14
     5.3.  LISP+ALT Router (or ALT router for short)  . . . . . . . . 12
     5.4.  ITR and ETR in a LISP+ALT Environment  . . . . . . . . . . 13
     5.5.  Use of GRE and BGP between LISP+ALT Routers  . . . . . . . 13 16
   6.  EID Prefix  EID-prefix Propagation and Map-Request Forwarding  . . . . . . 14 17
     6.1.  Changes to ITR behavior with LISP+ALT  . . . . . . . . . . 14 17
     6.2.  Changes to ETR behavior with LISP+ALT  . . . . . . . . . . 14 17
   7.  BGP configuration and protocol considerations  . . . . . . . . 16 19
     7.1.  Autonomous System Numbers (ASNs) in LISP+ALT . . . . . . . 16 19
     7.2.  Sub-Address Family Identifier (SAFI) for LISP+ALT  . . . . 16 19
   8.  EID-Prefix  EID-prefix Aggregation . . . . . . . . . . . . . . . . . . . . 17 20
     8.1.  Traffic engineering with LISP and LISP+ALT . . . . . . . . 17 20
     8.2.  Edge aggregation and dampening . . . . . . . . . . . . . . 18 21
   9.  Connecting sites to the ALT network  . . . . . . . . . . . . . 19 22
     9.1.  ETRs originating information into the ALT  . . . . . . . . 19 22
     9.2.  ITRs Using the ALT . . . . . . . . . . . . . . . . . . . . 19 22
   10. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 21 24
   11. Security Considerations  . . . . . . . . . . . . . . . . . . . 22 25
     11.1. Apparent LISP+ALT Vulnerabilities  . . . . . . . . . . . . 22 25
     11.2. Survey of LISP+ALT Security Mechanisms . . . . . . . . . . 23 26
     11.3. Using existing Use of new IETF standard BGP Security mechanisms . . . . . . . . . . 23 26
   12. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 24 27
   13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25 28
     13.1. Normative References . . . . . . . . . . . . . . . . . . . 25 28
     13.2. Informative References . . . . . . . . . . . . . . . . . . 25 28
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26 29

1.  Requirements Notation

   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 [RFC2119].

2.  Introduction

   This document describes a method of building an alternative logical
   topology for managing Endpoint identifier Alternative Logical
   Topology (ALT) to Routing Locator mappings
   using be used by the Locator/ID Separation Protocol [LISP].
   (LISP) to find Endpoint Identifier (EID) to Routing Locator (RLOC)
   mappings.  This logical topology uses existing technology and tools,
   specifically the Border Gateway Protocol [RFC4271] and its multi-protocol multi-
   protocol extension [RFC2858], along with the Generic Routing
   Encapsulation [RFC2784] protocol to construct an overlay network of
   devices that advertise (ALT Routers) which operate on EID-prefixes only.  These Endpoint Identifier Prefix Aggregators hold
   hierarchically-assigned pieces and use EIDs as
   forwarding destinations.

   ALT Routers advertise hierarchically-delegated segments of the Endpoint Identifier space EID
   namespace (i.e., prefixes) and their next hops toward the rest of the ALT; they also
   forward traffic destined for an EID covered by one of those prefixes
   toward the network element which is authoritative for Endpoint Identifier-to-Routing Locator mapping
   for that prefix.  Tunnel routers can use this overlay to make queries
   against and respond to mapping requests made against EID (i.e.
   is the distributed
   Endpoint Identifier-to-Routing Locator mapping database.  Note origin of the
   database is distributed (as described advertisement of the EID-to-RLOC mapping which
   applies to that EID).  Map Resolvers (MRs; see [LISP-MS]) and, in
   some cases, Ingress Tunnel Routers (ITRs) use this overlay to send
   mapping requests (using [LISP]) and is stored in to the
   ETRs.

   Note Egress Tunnel Routers (ETRs)
   that an important design goal of LISP+ALT hold the EID-to-RLOC mappings for a particular EID-prefix

   It is important to minimize note that the
   number of changes ALT does not distibute actual EID-
   to-RLOC mappings.  What it does provide is a forwarding path from an
   ITR (or MR) which requires an EID-to-RLOC mapping to existing hardware and/or software an ETR which
   holds that are
   required mapping.  The ITR/MR uses this path to send an ALT
   Datagram (see Section 4) to deploy an ETR which then responds with a Map-
   Reply containing the needed mapping system.  It information.

   One design goal for LISP+ALT is envisioned that in most
   cases to use existing technology can be used wherever
   possible.  To this end, the ALT is intended to be built using off-
   the-shelf routers which already implement and deploy LISP+
   ALT.  Since the deployment of LISP+ALT adds new required protocols (BGP
   and GRE); little, if any, LISP-specific modifications should be
   needed for such devices to be deployed on the
   network, existing devices not need changes or upgrades.  They can
   function as they ALT.  Note, though,
   that organizational and operational considerations suggest that ALT
   Routers be both logically and physically separate from the "native"
   Internet packet transport system; deploying this overlay on those
   routers which are to realize an underlying already participating in the global routing system
   and robust physical
   topology. actively forwarding Internet traffic is not recommended.

   The remainder of this document is organized as follows: Section 3
   provides the definitions of terms used in this document.  Section 4
   outlines the basic LISP 1.5 model.  Section 5 provides a basic
   overview of the LISP Alternate Topology architecture, and Section 6
   describes how the ALT uses BGP to propagate Endpoint Identifier
   reachability over the overlay network.  Section 8 describes the
   construction of the ALT aggregation hierarchy, and Section 9
   discusses how LISP+ALT elements are connected to form the overlay
   network.

3.  Definition of Terms

   LISP+ALT operates on two name spaces and introduces a new network
   element, the LISP+ALT Router (see below).  This section provides
   high-level definitions of the LISP+ALT name spaces, network elements,
   and message types.

   The

    Alternative Logical Topology (ALT):  The virtual overlay network
      made up of tunnels between EID Prefix Aggregators. LISP+ALT Routers.  The Border Gateway
      Protocol (BGP) runs between ALT routers Routers and is used to carry
      reachability information for EID prefixes.

   Legacy Internet: EID-prefixes.  The portion of ALT provides a way
      to forward Map-Requests (and, if supported, Data Probes) toward
      the Internet which does not run LISP ETR that "owns" and EID-prefix.  As a tunneled overlay, its
      performance is expected to be quite limited so use of it to
      forward high-bandwidth flows of Data Probes is strongly
      discouraged (see Section 4.3 for additional discussion).

    Legacy Internet:  The portion of the Internet which does not run
      LISP and does not participate in LISP+ALT.

   LISP+ALT

    ALT Router:  The devices which run on the ALT.  The ALT is a static
      network built using tunnels between LISP+ALT routers. ALT Routers.  These routers
      are deployed in a hierarchy roughly-hierarchical mesh in which routers at
      each level in the this hierarchy topology are responsible for aggregating all
      EID EID-
      prefixes learned from those logically "below" them and advertising
      summary prefixes to the routers those logically "above" them.  All prefix  Prefix learning
      and propagation between levels ALT Routers is done using BGP.  A LISP+ALT router  An ALT
      Router at the lowest level, or "edge" of the ALT, learns EID EID-
      prefixes from its "client" ETRs.  See Section 4.1 for a
      description of how EID prefixes EID-prefixes are learned at the "edge" of the
      ALT.  See also Section 7 for details on how BGP is configured
      between the different network elements.

      The primary function of LISP+ALT routers is to provide a
      lightweight  When an ALT Router
      receives an ALT Datagram, it looks up the destination EID in its
      forwarding infrastructure for LISP control-plane
      messages (Map-Request and Map-Reply), table (composed of EID prefix routes it learned from
      neighboring ALT Routers) and forwards it to transport data
      packets when the packet has the same destination address in both logical next-hop
      on the inner (encapsulating) destination and outer destination
      addresses ((i.e., a Data Probe packet). overlay network.

    Endpoint ID (EID):  A 32-bit (for IPv4) or 128-bit (for ipv6) value
      used in to identify the ultimate source and or destination address fields of the first
      (most inner) LISP header of for a LISP-
      encapsulated packet.  See [LISP] for details.

    EID-prefix:  A packet that is emitted by
      a system contains set of EIDs delegated in its headers and LISP headers a power-of-two block.  EID-
      prefixes are
      prepended only when routed on the packet reaches an Ingress Tunnel Router
      (ITR) ALT (not on the data path global Internet) and
      are expected to the destination EID.

      In LISP+ALT, EID-prefixes MUST BE be assigned in a hierarchical manner (in power-of-two) such that
      they can be aggregated by LISP+ ALT routers.  In addition, Routers.  Such a block is
      characterized by a prefix and a length.  Note that while the ALT
      routing system considers an EID-prefix to be an opaque block of
      EIDs, an end site may have site-local put site-local, topologically-relevant
      structure in
      how EIDs are topologically organized (subnetting) into an EID-prefix for routing
      within the site; this structure is not visible to the global
      routing system.

   EID-Prefix Aggregate: intra-site routing.

    Aggregated EID-prefixes:  A set of individual EID-prefixes said to be aggregatable that have
      been aggregated in the [RFC4632] sense.  That is, an EID-Prefix aggregate is
      defined to be

    Map Server (MS):   An edge ALT Router that provides a single contiguous power-of-two EID-prefix block.
      Such registration
      function for non-ALT-connected ETRs, originates EID-prefixes into
      the ALT on behalf of those ETRs, and forwards Map-Reqeusts to
      them.  See [LISP-MS] for details.

    Map Resolver (MR):   An edge ALT Router that accepts an Encapsulated
      Map-Reqeust from a block is characterized by non-ALT-connected ITR, decapsulates it, and
      forwards it on to the ALT toward the ETR which owns the requested
      EID-prefix.  See [LISP-MS] for details.

    Ingress Tunnel Router (ITR):   A router which sends LISP Map-
      Requests or encapsulates IP datagrams with LISP headers, as
      defined in [LISP].  In this document, the term refers to any
      device implementing ITR functionality, including a prefix Proxy-ITR (see
      [LISP-IW]).  Under some circumstances, a LISP Map Resolver may
      also originate Map-Requests (see [LISP-MS]).

    Egress Tunnel Router (ETR):   A router which sends LISP Map-Replies
      in response to LISP Map-Requests and decapsulates LISP-
      encapsulated IP datagrams for delivery to end systems, as defined
      in [LISP].  In this document, the term refers to any device
      implementing ETR functionality, including a length. Proxy-ETR (see
      [LISP-IW]).  Under some circumstances, a LISP Map Server may also
      respond to Map-Requests (see [LISP-MS]).

    Routing Locator (RLOC):  An  A routable IP address of an egress for a LISP tunnel
      router
      (ETR).  It is (ITR or ETR).  Also the output of a EID-to-RLOC mapping lookup.  An EID
      lookup; an EID-prefix maps to one or more RLOCs.  Typically, RLOCs
      are numbered from topologically-aggregatable blocks that are
      assigned to a site at each point to which it attaches to the
      global Internet; where the topology is defined by the connectivity
      of provider networks, networks.  RLOCs can be thought of as Provider
      Aggregatable (PA) addresses.
      Note that in LISP+ALT,  Routing for RLOCs are is not carried by LISP+ALT routers. on
      the ALT.

    EID-to-RLOC Mapping:  A binding between an EID EID-prefix and the RLOC-set set of
      RLOCs that can be used to reach the EID.  The term "mapping" refers it; sometimes referred to an
      EID-to-RLOC mapping.

    EID Prefix simply
      as a "mapping".

    EID-prefix Reachability:  An EID prefix EID-prefix is said to be "reachable" if
      one or more of its locators are reachable.  That is, an EID prefix EID-prefix
      is reachable if the ETR (or its proxy) that is authoritative for a
      given EID-to-RLOC mapping is reachable.

    Default Mapping:  A Default Mapping is a mapping entry for EID-
      prefix 0.0.0.0/0 (0::/0 for ipv6).  It maps to a locator-set used
      for all EIDs in the Internet.  If there is a more specific EID-
      prefix in the mapping cache it overrides the Default Mapping
      entry.  The Default Mapping route can be learned by configuration or
      from a Map-Reply message.

    ALT Default Route:  A Default Route in the context of LISP+ALT is a EID-
      prefix EID-prefix value of 0.0.0.0/0 (or 0::/0 for
      ipv6) which is advertised
      by BGP on top of may be learned from the ALT. ALT or statically configured
      on an edge ALT Router.  The Default ALT-Default Route is used to create defines a forwarding
      path for a packet to be sent into the ALT (and ALT
      datagram) on a router which does
      not have a full ALT forwarding database.

4.  The LISP 1.5 LISP+ALT model

   As documented in [LISP], the LISP 1.5

   The LISP+ALT model uses the same basic query/response protocol machinery as LISP 1.0. that
   is documented in [LISP].  In particular, LISP+
   ALT LISP+ALT provides two mechanisms for types
   packet that an ITR can originate to obtain EID-to-RLOC mappings
   (both mappings:

   Map-Request:  A Map-Request message is sent into the ALT to request
      an EID-to-RLOC mapping.  The ETR which owns the mapping will
      respond to the ITR with a Map-Reply message.  Since the ALT only
      forwards on EID destinations, the DA of these techniques are described in more detail in
   Section 9.2): the Map-Request sent on
      the ALT MUST be an EID.  See [LISP] for the format of Map-Request
      and Map-Reply packets.

   Data Probe:  An  Alternatively, an ITR may encapsulate and send the first few
      data packets packet destined for a EID with no known RLOCs into the ALT
      to as
      a Data Probe.  This might be done minimize packet loss and to
      probe for the mapping; mapping.  As above, the authoritative ETR for the
      EID-prefix will respond to the ITR with a Map-Reply message when
      it receives the data packet over the ALT.  As a side-effect, the
      encapsulated data packet is delivered to the end-system at the ETR
      site.  Note that in this
      case, the Data Probe the inner Destination Address
      (DA), which is an EID, is copied to the outer DA and is so that the
      resulting packet can be routed over the ALT.

   Map-Request:  An ITR may also send a Map-Request message into the ALT
      to request the mapping.  As in the Data Probe case, the
      authoritative ETR will respond to the ITR with a Map-Reply
      message.  Since the ALT only forwards on EID destinations, the DA
      of the Map-Request sent in to the ALT MUST be an EID.  See [LISP] Section 4.3 for
      caveats on the format usability of Map-Request and Map-Reply packets.

   ALT datagram:  A Data Probes.

   The term "ALT Datagram" is short-hand for a Map-Request or Data Probe
   to be sent into or forwarded on the ALT.  Note that while the outer
   header Source Address of an ALT Datagram is currently expected to be
   an RLOC, there may be situations (i.e. for experimentation with
   caching in intermediate ALT nodes) where an EID would be used to
   force a Map-Reply to be routed back through the ALT.

4.1.  Routeability of EIDs

   As with

   A LISP 1.0, EIDs are routable EID has the same syntax as IP address and can be used,
   unaltered, as the source and or destination addresses in of an IP datagrams.  Unlike in LISP
   1.0, LISP 1.5 datagram.  In
   general, though, EIDs are not routable on the public Internet; instead,
   they are only routed over LISP+
   ALT provides a separate, virtual topology referred to network, known as the LISP
   Alternative Virtual Network. Logical Topology (ALT) on which a datagram using an EID
   as a destination address may be transmitted.  This network is built
   as an overlay on the public Internet using tunnels to interconnect LISP+ALT
   routers.
   ALT Routers.  BGP is run runs over these tunnels to propagate the path
   information needed to route forward ALT datagrams. Datagrams.  Importantly, while the
   ETRs are the source(s) of the unaggregated EID prefix data, EID-prefixes, LISP+ALT
   uses existing BGP mechanisms to aggressively aggregate this information.  Note

4.1.1.  Mechanisms for an ETR to originate EID-prefixes

   There are three ways that an ETR may originate its mappings into the
   ALT:

   1.  By registration with a Map Server as documented in [LISP-MS].
       This is not required the common case and is expected to participate (or prevented from
   participating) in LISP+ALT; be used by the
       majority of ETRs.

   2.  Using a "static route" on the ALT.  Where no Map-Server is
       available, an ETR edge ALT Router may choose be configured with a "static
       EID-prefix route" pointing to an ETR.

   3.  Edge connection to communicate the ALT.  If a site requires fine- grained
       control over how its
   mappings EID-prefixes are advertised in to the ALT,
       it may configure its serving LISP+ALT router(s) using subscription time
   static configuration or through ETR(s) with tunnel and BGP connections to
       edge ALT Routers.

4.1.2.  Mechanisms for an ITR to forward to EID-prefixes

   There are three ways that an ITR may send ALT Datagrams:

   1.  Through a dynamic mechanism such Map Resolver as that
   described documented in [LISP-MS].  An  This is the
       common case and is expected to be used by the majority of ITRs.

   2.  Using a "default route".  Where a Map Resolver is not available,
       an ITR may similarly use be configured with a static EID
   "default route" or other configuration ALT Default Route pointing
       to an edge ALT Router.

   3.  Edge connection to the ALT.  If a site requires fine-grained
       knowledge of what prefixes exist on the ALT, it may configure its
       ITR(s) with tunnel and BGP connections to edge ALT Routers.

4.1.3.  Map Server Model preferred

   The ALT-connected ITR and ETR cases are expected to be rare, as described in [LISP-MS] the
   Map Server/Map Resolver model is both simpler for an ITR/ETR operator
   to
   avoid use, and provides a more general service interface to not only the complexity of participating
   ALT, but also to other mapping databases that may be developed in the ALT.
   future.

4.2.  Connectivity to non-LISP sites

   As stated above, EIDs used as IP addresses by LISP sites are not
   routable on the public Internet.  This implies that, absent a
   mechanism for communication between LISP and non-LISP sites,
   connectivity between them is not possible.  To resolve this problem,
   an "interworking" technology has been defined; see [Interworking] [LISP-IW] for
   details.

4.3.  Caveats on the use of Data Probes

   It is worth noting that there has been a great deal of discussion and
   controversy about whether Data Probes are a good idea.  On the one
   hand, using them offers a method of avoiding the "first packet drop"
   problem when an ITR does not have a mapping for a particular EID-
   prefix.  On the other hand, forwarding data packets on the ALT would
   require that it either be engineered to support relatively high
   traffic rates, which is not generally feasible for a tunneled
   network, or that it be carefully designed to aggressively rate- limit rate-limit
   traffic to avoid congestion or DoS attacks.  There are may also other be issues involving
   caused by different latency or other differences performance characteristics
   between the ALT path
   that taken by an initial a Data Probe would take and the
   "Internet" path that taken by subsequent packets on the same flow would take once a
   mapping were is in place on an ITR.  For these and other reasons use of
   Data Probes should be considered experimental and should be disabled
   by default in all ITR implementations.

5.  LISP+ALT: Overview

   LISP+ALT is a hybrid push/pull architecture.  Aggregated EID prefixes EID-prefixes
   are "pushed" advertised among the LISP+ALT routers and, optionally, out ALT Routers and to those (rare) ITRs
   (which may elect that
   are directly connected via a tunnel and BGP to receive the aggregated information, as opposed to
   simply using a default mapping). ALT.  Specific
   EID-to-RLOC mappings are
   "pulled" requested by ITRs an ITR (and returned by an ETR)
   using LISP when they it sends a request either send explicit LISP requests via a Map Resolver or data
   packets on the alternate topology that result in triggered replies
   being generated by ETRs. to an
   edge ALT Router.

   The basic idea embodied in LISP+ALT is to use BGP, running over on a
   tunneled overlay network, network (the ALT), to establish reachability required to route between
   ALT datagrams over an alternate logical topology (ALT). Routers.  The ALT BGPRoute Information Base (RIB) is comprised of EID prefixes
   EID-prefixes and associated next hops.  LISP+ALT routers  ALT Routers interconnect
   using eBGP BGP and propagate EID EID-prefix updates among themselves.  EID-
   prefix updates, which are information is learned over eBGP connections
   to authoritative ETRs, or by from ETRs at the "edge" of the ALT
   either through the use of the Map Server interface (the commmon
   case), static configuration.  ITRs may also
   eBGP peer with one configuration, or more LISP+ALT by BGP-speaking ETRs.

   An ITR use the ALT to learn the best ALT router to
   use to forward path for forwarding an ALT datagram for
   Datagram destined to a particular prefix; in most
   cases, an EID-prefix.  An ITR will have normally
   use a default EID mapping pointing Map Resolver to one send its ALT Datagrams on to the ALT but may,
   in unusual circumstances, use a static ALT Default Route or more
   LISP+ALT routers. connect
   to the ALT using BGP.

   Note that while this document specifies the use of Generic Routing
   Encapsulation (GRE) as a tunneling mechanism, there is no reason that
   an
   parts of the ALT cannot be built using other tunneling technologies.  In technologies,
   particularly in cases where GRE does not meet security, management,
   or other operational
   requirements, it is reasonable to use another tunneling technology
   that does. requirements.  References to "GRE tunnel" in
   later sections of this document should therefore not be taken as
   prohibiting or precluding the use of other, available other tunneling mechanisms.
   Note also that two
   LISP+ALT routers ALT Routers that are directly adjacent (with no
   layer-3 router hops between them) need not use a tunnel between them;
   in this case, BGP may be configured across the interfaces that
   connect to their common subnet and that subnet is then considered to
   be part of the ALT topology.  Use of techniques, techniques such as "eBGP multihop",
   multihop" to forward connect ALT
   datagrams through routers Routers that do not participate share a tunnel or common
   subnet is not recommended as the non-ALT Routers in between the ALT routing, is
   Routers in such a configuration may not recommended. have information necessary to
   forward ALT Datagrams destined to EID-prefixes exchanged across that
   BGP session.

   In summary, LISP+ALT uses BGP to propagate EID-prefix update
   information to facilitate forwarding build paths through ALT Routers so
   that an ALT datagram Datagram sent in to the ALT can be forwarded to the ETR
   that holds the EID-to-RLOC mapping for that EID-prefix.  This
   reachability is carried as IPv4 or IPv6 ipv6 NLRI without modification
   (since an EID
   prefix EID-prefix has the same syntax as IPv4 or IPv6 ipv6 address
   prefix).  LISP+ALT
   routers eBGP  ALT Routers BGP peer with one another, forming the ALT.  A LISP+ALT
   router  An
   ALT Router near the edge learns EID prefixes EID-prefixes originated by
   authoritative ETRs.  This may be via eBGP with though the ETRs, Map Server interface, by
   static configuration,
   or through some other dynamic mechanism such as that defined in
   [LISP-MS].  A LISP+ALT router be via BGP with the ETRs.  An ALT Router may
   also be configured to aggregate EID
   prefixes EID-prefixes received from ETRs or
   from other LISP+ALT routers that are topologically "downstream" from
   it.

5.1.  ITR traffic handling

   When an ITR receives a packet originated by an end system within withind its
   site (i.e. a host for which the ITR is the exit path out of the site)
   and the destination EID for that packet is not known in the ITR's
   mapping cache, the ITR encapsulates the packet in creates either a LISP header, copying Map-Request for the
   inner
   destination address (EID) to EID or the outer destination address
   (RLOC), and transmits it through original packet encapsulated as a GRE tunnel Data Probe.
   The result, known as an ALT Datagram, is then sent to a LISP+ALT router in
   the an ALT Router
   (see also [LISP-MS] for non-ALT-connected ITRs, noting that
   an ITR cannot send Data
   Probes cannot be sent to a Map-Server). Map-Resolver).  This "first hop"
   LISP+ALT router ALT
   Router uses EID-prefix routing information learned from other LISP+ALT routers ALT
   Routers via BGP to guide the packet to the ETR which "owns" the
   prefix.  Upon receipt by the ETR, normal LISP processing occurs: the
   ETR responds to the ITR with a LISP Map-Reply that lists the RLOCs
   (and, thus, the ETRs to use) for the EID prefix.  The EID-prefix.  For Data Probes,
   the ETR also de-encapsulates decapsulates the packet and transmits it toward its
   destination.

   Upon receipt of the Map-Reply, the ITR installs the RLOC information
   for a given prefix into a local mapping database.  With these mapping
   entries stored, additional packets destined to the given EID prefix EID-prefix
   are routed directly to a viable ETR an RLOC without use of the ALT, until either
   the entry's TTL has expired, or the ITR can otherwise find no
   reachable ETR.  Note that a valid mapping (not timed-out) may exist
   that contains no reachable RLOCs (i.e. all paths to that ETR are
   down); in this case, packets destined to the EID prefix EID-prefix are dropped,
   not routed through the ALT. dropped.

   Traffic routed over on to the ALT therefore consists of:

   o  EID prefix Map-Requests, solely of ALT Datagrams, i.e.
   Map-Requests and

   o  data packets destined for those EID prefixes while the ITR awaits
      map replies Data Probes (if supported).

5.2.  EID Assignment - Hierarchy and Topology

   EID-prefixes will be allocated to a LISP site by Internet Registries.
   Multiple allocations may not be in power-of-2 blocks.  But when they
   are, they will be aggregated into a single, advertised EID-prefix.
   The ALT network is built in a tree-structured hierarchy to allow
   aggregation at merge points in the tree.  Building such a structure
   should minimize the number of EID-prefixes carried by LISP+ALT nodes
   near the top of the hierarchy.

   Since the ALT will does not need in response to change due to subscription changes in policy,
   subscription, or policy
   reasons, the underlying physical connectivity, the topology
   can remain relatively static and aggregation can be sustained.
   Because routing on the ALT uses BGP, the same rules apply for
   generating aggregates; in particular, a LISP+ALT
   router ALT Router should only be
   configured to generate an aggregate if it is configured with BGP
   sessions to all of the originators of components (more-specifics
   prefixes) of that aggregate; not aggregate.  Not all of the components of need to be
   present for the aggregate to be originated (some may be holes in the
   covering prefix and some may be down) but the aggregating router must
   be configured to learn the state of all of the components.

   As an example, consider ETRs that are originating EID prefixes EID-prefixes for
   10.1.0.0/24, 10.1.64.0/24, 10.1.128.0/24, and 10.1.192.0/24.  An ALT
   router
   Router should only be configured to generate an aggregate for
   10.1.0.0/16 if it has BGP sessions configured with all of these ETRs,
   in other words, only if it has sufficient knowledge about the state
   of those prefixes to summarize them.

   Under what circumstances the ALT router Router actually generates the
   aggregate is a matter of local policy: in some cases, it will be
   statically configured to do so at all times with a "static discard"
   route.  In other cases, it may be configured to only generate the
   aggregate prefix if at least one of the components of the aggregate
   is learned via BGP.

   This implies that two

   An ALT routers that share Router MUST NOT genearte an overlapping set of
   prefixes must exchange those prefixes if either is to generate and
   export a covering aggregate for those prefixes.  It also implies that
   an ETR which connects includes a non-
   LISP-speaking hole unless it can be configured to the ALT using BGP must maintain BGP sessions return a Negative
   Map-Reply with all of the action="Natively-Forward" (see [LISP]) if it receives
   an ALT routers Datagram that are configured to originate an
   aggregate which covers matches that prefix.  See also [LISP-MS] for hole.  If it receives an
   example of other ways ALT
   Datagram that matches a LISP-speaking hole that prefix origin consistency and aggregation
   are maintained.

   Note: much is currently uncertain about the best way to build the ALT
   network; as testing and prototype deployment proceeds, not
   reachable, it should return a guide to how
   to best build the ALT network will Negative Map-Reply with action="drop".
   Negative Map-Replies should be developed.

5.3.  LISP+ALT Router (or ALT router for short)

   A LISP+ALT Router has the following functionality:

   1.  It runs, at a minimum, the eBGP part of the BGP protocol.

   2.  It supports a separate RIB which uses next-hop GRE tunnel
       interfaces for forwarding ALT datagrams.

   3.  It can act as returned with a "proxy-ITR" to support non-LISP sites.

   4.  It can act as an ETR, or short TTL, as a recursive or re-encapsulating ITR
       to reduce mapping tables
   specified in site-based LISP routers.

5.4.  ITR and ETR in a LISP+ALT Environment

   An ITR using LISP+ALT may have additional functionality as follows:

   1.  If it is also acting [LISP-MS].  Note that an off-the-shelf, non-LISP-
   speaking router configured as a LISP+ALT Router, it sends an aggregating ALT datagrams
       on the BGP best path computed GRE tunnel for each EID prefix.

   2.  When acting solely as Router cannot send
   Negative Map-Replies, so such a ITR, it sends router must never originate an
   aggregate that includes a non-LISP-speaking hole.

   This implies that two ALT datagrams directly Routers that share an overlapping set of
   prefixes must exchange those prefixes if either is to generate and
   export a
       configured LISP+ALT router.

   An covering aggregate for those prefixes.  It also implies that
   an ETR which connects to the ALT using LISP+ALT may also behave slightly differently:

   1.  If it is also acting as a LISP+ALT router, it advertises its
       configured EID-prefixes into BGP for distribution through must maintain BGP sessions
   with all of the
       ALT.

   2.  It receives ALT datagrams only from its "upstream" LISP+ALT
       routers over the GRE tunnel(s) Routers that are configured to it/them.  It
       responds with Map-Replies originate an
   aggregate which covers that prefix.  See also [LISP-MS] for the EID prefixes an
   example of other ways that it "owns".

5.5. prefix origin consistency and aggregation
   are maintained.

   Note: much is currently uncertain about the best way to build the ALT
   network; as testing and prototype deployment proceeds, a guide to how
   to best build the ALT network will be developed.

5.3.  Use of GRE and BGP between LISP+ALT Routers

   The ALT network is built using GRE tunnels between LISP+ALT routers.
   eBGP ALT Routers.  BGP
   sessions are configured over those tunnels, with each LISP+ALT
   router ALT Router
   acting as a separate AS "hop" in a Path Vector for BGP.  For the
   purposes of LISP+ALT, the AS-path is used solely as a shortest-
   path shortest-path
   determination and loop-avoidance mechanism.  Because all next-
   hops next-hops
   are on tunnel interfaces, no IGP is required to resolve those
   next-hops next-
   hops to exit interfaces.

   LISP+ALT's use of GRE and BGP reduces provider Operational Expense
   (OPEX) because no new protocols need to be either defined or used on
   the overlay topology.  Also, since tunnel IP addresses are local in
   scope, no coordination is needed for their assignment; any addressing
   scheme (including private addressing) can be used for tunnel
   addressing.

6.  EID Prefix  EID-prefix Propagation and Map-Request Forwarding

   As described in Section 9.2, an ITR may send either a Map-Request or
   a data probe sends an ALT Datagram to find a given
   EID-to-RLOC mapping.  The ALT provides the infrastructure that allows
   these requests to reach the authoritative ETR.

   Note that, that under normal circumstances, circumstances Map-Replies are not sent over
   the ALT - an ETR sends a Map-Reply to the source RLOC learned from
   the original Map-Request.  There may be scenarios, perhaps to
   encourage caching of EID-to-RLOC mappings by ALT routers, Routers, where Map-
   Replies could be sent over the ALT or where a "first-hop" ALT router
   might modify the originating RLOC on a Map-Request received from an
   ITR to force the Map-Reply to be sent returned to it; these the "first-hop" ALT
   Router.  These cases will not be supported by initial LISP+ALT
   implementations but may be subject to future experimentation.

   LISP+ALT routers

   ALT Routers propagate mapping path information for use via BGP ([RFC4271]) that is
   used by ITRs (when
   sending to send ALT datagrams) using eBGP [RFC4271]. eBGP Datagrams toward the appropriate ETR for
   each EID-prefix.  BGP is run on the
   inter-LISP+ALT router inter-ALT Router links, and
   possibly between an edge ("last hop") LISP+ALT router ALT Router and an ETR or
   between an edge ("first hop")
   LISP+ALT router ALT Router and an ITR.  The ALT eBGP BGP RIB
   consists of aggregated
   EID prefixes EID-prefixes and their next hops toward the
   authoritative ETR for that EID prefix. EID-prefix.

6.1.  Changes to ITR behavior with LISP+ALT ITR behavior with LISP+ALT

   As previously described, an ITR will usually use the Map Resolver
   interface and will send its Map Requests to a Map Resolver.  When using LISP+ALT, an
   ITR instead connects via tunnels and BGP to the ALT, it sends ALT datagrams
   Datagrams to one of its "upstream" LISP+ALT routers; ALT Routers; these are sent only
   to obtain new EID-
   to-RLOC EID-to-RLOC mappings - RLOC probe and cache TTL refresh
   Map-Requests are not sent on the ALT.  As in basic LISP, it should
   use one of its RLOCs as the source address of these queries; it
   should explicitly not use a tunnel interface as the source address as
   doing so will cause replies to be forwarded over the tunneled
   topology and may be problematic if the tunnel interface address is
   not explicitly routed throughout the ALT.  If the ITR is running BGP
   with the LISP+ALT router(s), it selects the appropriate LISP+ALT router ALT Router
   based on the BGP information received.  If it is not running BGP, it
   uses static
   configuration a statically-configued ALT Default Route to select a LISP+ALT router; in the general case, this
   will effectively be an "EID-prefix default route". ALT
   Router.

6.2.  Changes to ETR behavior with LISP+ALT

   If

   As previously described, an ETR will usually use the Map Server
   interface (see [LISP-MS]) and will register its EID-prefixes with its
   configured Map Servers.  When an ETR instead connects using BGP to
   one or more LISP+ALT router(s), ALT Routers, it
   simply announces its EID-prefix EID-prefix(es) to those LISP+ALT routers. ALT
   Routers.  Note that when an ETR generates a Map-Reply message to
   return to a querying ITR, it sends it to the ITR's source-RLOC (i.e.,
   on the underlying Internet topology, not on the ALT; this avoids any
   latency penalty (or "stretch") that might be incurred by routing over
   the ALT).

7.  BGP configuration and protocol considerations

7.1.  Autonomous System Numbers (ASNs) in LISP+ALT

   The primary use of BGP today is to define the global Internet routing
   topology in terms of its participants, known as Autonomous Systems.
   LISP+ALT specifies the use of BGP to create a global overlay network
   (the ALT) for finding EID-to-RLOC
   mapping database which, while mappings.  While related to the
   global routing database, the ALT serves a very different purpose and
   is organized into a very different hierarchy.  Because LISP+ALT does
   use BGP, however, it uses ASNs in the paths that are propagated among LISP+ALT routers.
   ALT Routers.  To avoid confusion, it needs to be stressed that that
   these LISP+ALT ASNs use a new numbering space that is unrelated to
   the ASNs used by the global routing system.  Exactly how this new
   space will be assigned and managed will be determined during experimental the
   deployment of LISP+ALT.

   Note that the LISP+ALT routers ALT Routers that make up the "core" of the ALT will not
   be associated with any existing core-Internet ASN because
   topology, hierarchy, and aggregation boundaries are the ALT
   topology is completely separate from from, and independent of of, the global
   Internet routing system.

7.2.  Sub-Address Family Identifier (SAFI) for LISP+ALT

   As defined by this document, LISP+ALT may be implemented using BGP
   without modification.  Given the fundamental operational difference
   between propagating global Internet routing information (the current, current
   dominant use of BGP) and managing the global EID-to-RLOC database creating an overlay network for finding EID-
   to-RLOC mappings (the use of BGP proposed by this document), it may
   be desirable to assign a new SAFI [RFC2858] to prevent operational
   confusion and difficulties, including the inadvertent leaking of
   information from one domain to the other.  At present, this document
   does not require the assignment of a new SAFI SAFI, but the authors
   anticipate that experimentation may suggest the need for one in the
   future.

8.  EID-Prefix  EID-prefix Aggregation

   The ALT BGP peering topology should be arranged in a tree-like
   fashion (with some meshiness), with redundancy to deal with node and
   link failures.  A basic assumption is that as long as the routers are
   up and running, the underlying topology Internet will provide alternative
   routes to maintain BGP connectivity among LISP+ALT routers. ALT Routers.

   Note that, as mentioned in Section 5.2, the use of BGP by LISP+ALT
   requires that information can only be aggregated where all active
   more-specific more-
   specific prefixes of a generated aggregate prefix are known.  This implies, for example, that if a given set of prefixes is used by
   multiple, ALT networks, those networks must interconnect and share
   information about all of the prefixes if either were to generate an
   aggregate prefix that covered all of them.  This is
   no different than the way that BGP route aggregation works in the
   existing global routing system: a service provider only generates an
   aggregate route if it is configured to learn to all prefixes that
   make up that aggregate.

8.1.  Traffic engineering with LISP and LISP+ALT

   It is worth noting that LISP+ALT does not directly propagate EID-to-
   RLOC mappings.  What it does is provide a mechanism for a LISP an ITR to
   find
   commonicate with the ETR that holds the mapping for a particular EID EID-
   prefix.  This distinction is important for several reasons.  First, it means
   that the
   since reachability of RLOCs is learned through the LISP ITR-ETR
   exchange so
   exchange, "flapping" of state information through (frequent BGP updates and withdrawals) is not likely
   nor can
   likely, and mapping information cannot become "stale" by due to slow
   propagation through the ALT BGP mesh.  Second, by deferring since an ITR learns an
   EID-to-RLOC mapping
   to an ITR-ETR exchange, directly from the ETR that owns it, it is
   possible to perform site-to-site traffic engineering through a combination of by setting the
   preference
   and and/or weight fields fields, and by returning including more-specific EID-to-RLOC EID-
   to-RLOC information in LISP Map-Reply messages.

   This is a powerful mechanism that can conceivably replace the
   traditional practice of routing prefix deaggregation for traffic
   engineering purposes.  Rather than propagating more-specific
   information into the global routing system for local- or regional-optimization regional-
   optimization of traffic flows, such more-
   specific more-specific information can be
   exchanged, through LISP (not LISP+ALT), on an as-needed basis between
   only those ITRs/ETRs (and, thus, site pairs) that need it; should it.  Should a
   receiving ITR decide that it does not wish to store such more-specific more-
   specific information, it has the option of discarding it as long as a
   shorter, covering EID prefix EID-prefix exists.  Not
   only does this greatly improve the scalability  Such an exchange of the global routing
   system but it also allows improved "more-
   specifics" between sites facilitates traffic engineering techniques engineering, by allowing
   richer and more fine-grained policies to be applied. applied without
   advertising additional prefixes into either the ALT or the global
   routing system.

8.2.  Edge aggregation and dampening

   Note also that normal BGP best common practices apply to the ALT network.
   In particular, first-hop ALT routers Routers will aggregate EID prefixes and
   dampen changes to them in the face of excessive updates.  Since EID EID-
   prefix assignments are not expected to change with anywhere as frequently as global
   routing BGP prefix reachability on the Internet, reachability, such dampening should be very rare rare,
   and might be worthy of logging as an exceptional event.  It is again
   worth noting that the ALT carries only EID
   prefixes, along with BGP-generated EID-prefixes, used to
   construct BGP paths to the ETRs that source
   those prefixes as advertisements travel over the logical topology; their owning ETRs; this set of information is considerablly
   considerably less volatile than the actual EID-to-RLOC mappings.

9.  Connecting sites to the ALT network

9.1.  ETRs originating information into the ALT

   EID prefix

   EID-prefix information is originated into the ALT by two three different
   mechanisms:

   eBGP:  An ETR usually participates

   Map Server:  In most cases, a site will configure its ETR(s) to
      register with one or more Map Servers (see [LISP-MS]), and does
      not participate directly in the ALT.

   BGP:  For a site requiring complex control over their EID-prefix
      origination into the ALT, an ETR may connect to the LISP+ALT
      overlay network by running eBGP BGP to one or more LISP+ALT router(s) ALT Router(s) over
      tunnel(s).  The ETR advertises reachability for its EID prefixes EID-prefixes
      over these
      eBGP BGP connection(s).  The LISP+ALT router(s) edge ALT Router(s) that
      receive(s) these prefixes then propagate(s) them into the ALT.
      Here the ETR is simply an eBGP BGP peer of LISP+ALT router(s) ALT Router(s) at the edge of
      the ALT.  Where possible, a LISP+ALT router an ALT Router that receives EID prefixes EID-prefixes
      from an ETR via eBGP BGP should aggregate that information.

   Configuration:  One or more LISP+ALT router(s) ALT Router(s) may be configured to
      originate an EID prefix EID-prefix on behalf of the non-BGP-speaking ETR that
      is authoritative for a prefix.  As in the case above, the ETR is
      connected to LISP+ALT router(s) ALT Router(s) using GRE tunnel(s) but rather than BGP
      being used, the LISP+ALT router(s) ALT Router(s) are configured with what are in
      effect "static routes" for the EID prefixes EID-prefixes "owned" by the ETR.
      The GRE tunnel is used to route Map-Requests to the ETR.  Note
      that the LISP+ALT router ALT Router could also serve as a proxy for its
      TCP-connected TCP-
      connected ETRs.

   Note:  in both all cases, an ETR may have connections register to multiple Map Servers or
      connect to multiple
      LISP+ALT routers ALT Routers for the following reasons:

      *  redundancy, so that a particular ETR is still reachable through
         the ALT even if
         one path or tunnel is unavailable.

      *  to connect to different parts of the ALT hierarchy if the ETR
         "owns" multiple EID-to-RLOC mappings for EID prefixes EID-prefixes that
         cannot be aggregated by the same LISP+ALT router ALT Router (i.e. are not
         topologically "close" to each other in the ALT).

9.2.  ITRs Using the ALT

   In order to source Map-Requests to the ALT or to route a Data Probe
   packet over the ALT, each ITR participating in the ALT establishes a
   connection to one or more LISP+ALT routers.  These connections can be
   either eBGP or TCP (as described above).

   In the case in which the ITR is running eBGP, the peer LISP+ALT
   routers use these connections to advertise highly aggregated EID-
   prefixes to the peer ITRs.  The ITR then installs the received
   prefixes into a forwarding table that is used to to send LISP Map-
   Requests to the appropriate LISP+ALT router.  In most cases, a LISP+
   ALT router will send a default mapping to its client ITRs so that
   they can send request for any EID prefix into the ALT.

   In the case in which ALT

   In the common configuration, an ITR is connected does not need to some set of LISP+ALT
   routers without eBGP, know anything
   about the ITR ALT, since it sends Map-Requests to any one of its
   connected LISP+ALT routers.

   An configured
   Map-Resolvers (see [LISP-MS]).  There are two exceptional cases:

   Static default:  If a Map Resolver is not available but an ITR may also choose is
      adjacent to send the first few data packets an ALT Router (either over a common subnet or through
      the use of a tunnel), it can use an ALT Default Route route to minimize packet loss
      cause all ALT Datagrams to be sent that ALT Router.  This case is
      expected to be rare.

   Connection to ALT:  A site with complex Internet connectivity needs
      may need more fine-grained distinction between traffic to LISP-
      capable and reduce mapping latency.  In this
   case, non-LISP-capable sites.  Such a site may configure
      each of its ITRs to connect directly to the data packet serves as ALT, using a mapping probe (Data Probe) tunnel
      and BGP connection.  In this case, the
   ETR which receives ITR will receive EID-prefix
      routes from its BGP connection to the data packet (over ALT Router and will LISP-
      encapsulate and send ALT Datagrams through the ALT) responds with a
   Map-Reply is sent tunnel to the ITR's source-RLOC using the underlying
   topology.  Note ALT
      Router.  Traffic to other destinations may be forwarded (without
      LISP encapsulation) to non-LISP next-hop routers that the use of Data Probes is discouraged at this
   time (see Section 4.3). ITR
      knows.

      In general, an ITR will establish connections that connects to the ALT does so only to LISP+ALT
   routers to ALT
      Routers at the "edge" of the ALT (typically two for redundancy) but
   there may also redundancy).
      There may, though, be situations where an ITR would connect to
      other
   LISP+ALT routers ALT Routers to receive additional, shorter path information
      about a portion of the ALT of interest to it.  This can be
      accomplished by establishing GRE tunnels between the ITR and the
      set of LISP+ALT routers ALT Routers with the additional information.  This is a
      purely local policy issue between the ITR and the LISP+ALT routers in
   question. ALT Routers in
      question.

   As described in [LISP-MS], Map-Resolvers do not accept or forward
   Data Probes; in the rare scenario that an ITR does support and
   originate Data Probes, it must do so using one of the exceptional
   configurations described above.  Note that the use of Data Probes is
   discouraged at this time (see Section 4.3).

10.  IANA Considerations

   This document makes no request of the IANA.

11.  Security Considerations

   LISP+ALT shares many of the security characteristics of BGP.  Its
   security mechanisms are comprised of existing technologies in wide
   operational use today.  Securing LISP+ALT is much simpler than today, so securing BGP.

   Compared to BGP, LISP+ALT routers are not topologically bound,
   allowing them to the ALT should be put in locations away from mostly a matter
   of applying the vulnerable AS
   border (unlike eBGP speakers). same technology that is used to secure the BGP-based
   global routing system (see Section 11.3 below).

11.1.  Apparent LISP+ALT Vulnerabilities

   This section briefly lists of the apparent known potential vulnerabilities of LISP+
   ALT.
   LISP+ALT.

   Mapping Integrity:  Can an attacker insert bogus mappings to black-
      hole (create a DoS) Denial-of-Service, or DoS attack) or intercept LISP
      data-plane packets?

   LISP+ALT router

   ALT Router Availability:  Can an attacker DoS the LISP+ALT
      routers ALT Routers
      connected to a given ETR? without access to  If a site's ETR cannot advertise its
      EID-to-RLOC mappings,
      a the site is essentially unavailable.

   ITR Mapping/Resources:  Can an attacker force an ITR or LISP+ALT
      router ALT Router to
      drop legitimate mapping requests by flooding it with random
      destinations that for which it will have to query for. generate large numbers of Map-
      Reqeusts and fill its mapping cache?  Further study is required to
      see the impact of admission control on the overlay network.

   EID Map-Request Exploits for Reconnaissance:  Can an attacker learn
      about a LISP destination sites' site's TE policy by sending legitimate mapping
      requests messages and then observing the RLOC mapping replies?  Is this
      information useful in attacking or subverting peer relationships?
      Note that any public LISP 1.0 has a mapping database will have similar data-plane data-
      plane reconnaissance issue.

   Scaling of LISP+ALT router ALT Router Resources:  Paths through the ALT may be of
      lesser bandwidth than more "direct" paths; this may make them more
      prone to high-volume denial-of-service attacks.  For this reason,
      all components of the ALT (ETRs and ALT routers) Routers) should be
      prepared to rate-limit traffic (ALT datagrams) Datagrams) that could be
      received across the ALT.

   UDP Map-Reply from ETR:  Since Map-Replies packets are sent directly from the
      ETR to the ITR's RLOC, the ITR's RLOC may be vulnerable to various
      types of DoS attacks. attacks (this is a general property of LISP, not an
      LISP+ALT vulnerability).

11.2.  Survey of LISP+ALT Security Mechanisms

   Explicit peering:  The devices themselves can both prioritize
      incoming packets packets, as well as potentially do key checks in hardware
      to protect the control plane.

   Use of TCP to connect elements:  This makes it difficult for third
      parties to inject packets.

   Use of HMAC Protected TCP BGP/TCP Connections:  HMAC is used to verify
      message integrity and authenticity, making it nearly impossible
      for third party devices to either insert or modify messages.

   Message Sequence Numbers and Nonce Values in Messages:  This allows
      for devices
      an ITR to verify that the mapping-reply packet was Map-Reply from an ETR is in response to the mapping-request
      a Map-Request originated by that they sent. ITR (this is a general property
      of LISP; LISP+ALT does not change this behavior).

11.3.  Using existing  Use of new IETF standard BGP Security mechanisms

   LISP+ALT's use of BGP allows for the ALT to take advantage of BGP
   security features designed for existing Internet BGP use.

   For example, should either sBGP [I-D.murphy-bgp-secr] or soBGP
   [I-D.white-sobgparchitecture] become widely deployed it expected that
   LISP+ALT could use these mechanisms to provide authentication of EID-
   to-RLOC mappings, and EID origination.

12.  Acknowledgments

   Many

   The authors would like to specially thank J. Noel Chiappa who was a
   key contributer to the design of the LISP-CONS mapping database (many
   ideas described in this document were developed during
   detailed discussions with Scott Brim from which made their way into LISP+ALT) and Darrel Lewis, who made many
   insightful comments on earlier versions of this document.  Additional
   thanks are due has continued
   to provide invaluable insight as the LISP effort has evolved.  Others
   who have provided valuable contributions include John Zwiebel, Hannu Flinck and
   Flinck, Amit Jain who offered many helpful
   suggestions for the -02 version. Jain, and Scott Brim.

13.  References

13.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2784]  Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
              Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
              March 2000.

   [RFC2858]  Bates, T., Rekhter, Y., Chandra, R., and D. Katz,
              "Multiprotocol Extensions for BGP-4", RFC 2858, June 2000.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.

   [RFC4632]  Fuller, V. and T. Li, "Classless Inter-domain Routing
              (CIDR): The Internet Address Assignment and Aggregation
              Plan", BCP 122, RFC 4632, August 2006.

13.2.  Informative References

   [I-D.murphy-bgp-secr]
              Murphy, S., "BGP Security Analysis",
              draft-murphy-bgp-secr-04 (work in progress),
              November 2001.

   [I-D.white-sobgparchitecture]
              White, R., "Architecture and Deployment Considerations for
              Secure Origin BGP (soBGP)",
              draft-white-sobgparchitecture-00 (work in progress),
              May 2004.

   [Interworking]

   [LISP]     Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,
              "Locator/ID Separation Protocol (LISP)",
              draft-ietf-lisp-06.txt (work in progress), January 2010.

   [LISP-IW]  Lewis, D., Meyer, D., Farinacci, D., and V. Fuller,
              "Interworking LISP with IPv4 and ipv6",
              draft-ietf-lisp-interworking-01.txt (work in progress),
              January 2010.

   [LISP]     Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,
              "Locator/ID Separation Protocol (LISP)",
              draft-ietf-lisp-06.txt (work in progress), January 2010.

   [LISP-MS]  Fuller, V. and D. Farinacci, "LISP Map Server",
              draft-ietf-lisp-ms-04.txt (work in progress),
              October 2009.

Authors' Addresses

   Vince Fuller
   Cisco
   Tasman Drive
   San Jose, CA  95134
   USA

   Email: vaf@cisco.com

   Dino Farinacci
   Cisco
   Tasman Drive
   San Jose, CA  95134
   USA

   Email: dino@cisco.com

   Dave Meyer
   Cisco
   Tasman Drive
   San Jose, CA  95134
   USA

   Email: dmm@cisco.com

   Darrel Lewis
   Cisco
   Tasman Drive
   San Jose, CA  95134
   USA

   Email: darlewis@cisco.com
--A6N2fC+uXW/VQSAv Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="draft-ietf-lisp-alt-03.txt" Network Working Group V. Fuller Internet-Draft D. Farinacci Intended status: Experimental D. Meyer Expires: August 21, 2010 D. Lewis Cisco February 17, 2010 LISP Alternative Topology (LISP+ALT) draft-ietf-lisp-alt-03.txt Abstract This document describes a method of building an Alternative Logical Topology (ALT) to be used by the Locator/ID Separation Protocol (LISP) to find Endpoint Identifier (EID) to Routing Locator (RLOC) mappings. The ALT is built as an overlay on the public Internet using existing technologies and tools, specifically the Border Gateway Protocol and the Generic Routing Encapsulation. An important design goal for LISP+ALT is to allow for the relatively easy deployment of a mapping system while minimizing changes to existing hardware and software. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 21, 2010. Copyright Notice Fuller, et al. Expires August 21, 2010 [Page 1] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 Copyright (c) 2010 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 BSD License. Fuller, et al. Expires August 21, 2010 [Page 2] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 Table of Contents 1. Requirements Notation . . . . . . . . . . . . . . . . . . . . 4 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 7 4. The LISP+ALT model . . . . . . . . . . . . . . . . . . . . . . 10 4.1. Routeability of EIDs . . . . . . . . . . . . . . . . . . . 10 4.1.1. Mechanisms for an ETR to originate EID-prefixes . . . 11 4.1.2. Mechanisms for an ITR to forward to EID-prefixes . . . 11 4.1.3. Map Server Model preferred . . . . . . . . . . . . . . 11 4.2. Connectivity to non-LISP sites . . . . . . . . . . . . . . 11 4.3. Caveats on the use of Data Probes . . . . . . . . . . . . 12 5. LISP+ALT: Overview . . . . . . . . . . . . . . . . . . . . . . 13 5.1. ITR traffic handling . . . . . . . . . . . . . . . . . . . 14 5.2. EID Assignment - Hierarchy and Topology . . . . . . . . . 14 5.3. Use of GRE and BGP between LISP+ALT Routers . . . . . . . 16 6. EID-prefix Propagation and Map-Request Forwarding . . . . . . 17 6.1. Changes to ITR behavior with LISP+ALT . . . . . . . . . . 17 6.2. Changes to ETR behavior with LISP+ALT . . . . . . . . . . 17 7. BGP configuration and protocol considerations . . . . . . . . 19 7.1. Autonomous System Numbers (ASNs) in LISP+ALT . . . . . . . 19 7.2. Sub-Address Family Identifier (SAFI) for LISP+ALT . . . . 19 8. EID-prefix Aggregation . . . . . . . . . . . . . . . . . . . . 20 8.1. Traffic engineering with LISP and LISP+ALT . . . . . . . . 20 8.2. Edge aggregation and dampening . . . . . . . . . . . . . . 21 9. Connecting sites to the ALT network . . . . . . . . . . . . . 22 9.1. ETRs originating information into the ALT . . . . . . . . 22 9.2. ITRs Using the ALT . . . . . . . . . . . . . . . . . . . . 22 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 11. Security Considerations . . . . . . . . . . . . . . . . . . . 25 11.1. Apparent LISP+ALT Vulnerabilities . . . . . . . . . . . . 25 11.2. Survey of LISP+ALT Security Mechanisms . . . . . . . . . . 26 11.3. Use of new IETF standard BGP Security mechanisms . . . . . 26 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28 13.1. Normative References . . . . . . . . . . . . . . . . . . . 28 13.2. Informative References . . . . . . . . . . . . . . . . . . 28 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29 Fuller, et al. Expires August 21, 2010 [Page 3] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 1. Requirements Notation 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 [RFC2119]. Fuller, et al. Expires August 21, 2010 [Page 4] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 2. Introduction This document describes a method of building an Alternative Logical Topology (ALT) to be used by the Locator/ID Separation Protocol (LISP) to find Endpoint Identifier (EID) to Routing Locator (RLOC) mappings. This logical topology uses existing technology and tools, specifically the Border Gateway Protocol [RFC4271] and its multi- protocol extension [RFC2858], along with the Generic Routing Encapsulation [RFC2784] protocol to construct an overlay network of devices (ALT Routers) which operate on EID-prefixes and use EIDs as forwarding destinations. ALT Routers advertise hierarchically-delegated segments of the EID namespace (i.e., prefixes) toward the rest of the ALT; they also forward traffic destined for an EID covered by one of those prefixes toward the network element which is authoritative for that EID (i.e. is the origin of the advertisement of the EID-to-RLOC mapping which applies to that EID). Map Resolvers (MRs; see [LISP-MS]) and, in some cases, Ingress Tunnel Routers (ITRs) use this overlay to send mapping requests (using [LISP]) to the Egress Tunnel Routers (ETRs) that hold the EID-to-RLOC mappings for a particular EID-prefix It is important to note that the ALT does not distibute actual EID- to-RLOC mappings. What it does provide is a forwarding path from an ITR (or MR) which requires an EID-to-RLOC mapping to an ETR which holds that mapping. The ITR/MR uses this path to send an ALT Datagram (see Section 4) to an ETR which then responds with a Map- Reply containing the needed mapping information. One design goal for LISP+ALT is to use existing technology wherever possible. To this end, the ALT is intended to be built using off- the-shelf routers which already implement the required protocols (BGP and GRE); little, if any, LISP-specific modifications should be needed for such devices to be deployed on the ALT. Note, though, that organizational and operational considerations suggest that ALT Routers be both logically and physically separate from the "native" Internet packet transport system; deploying this overlay on those routers which are already participating in the global routing system and actively forwarding Internet traffic is not recommended. The remainder of this document is organized as follows: Section 3 provides the definitions of terms used in this document. Section 4 outlines the basic LISP 1.5 model. Section 5 provides a basic overview of the LISP Alternate Topology architecture, and Section 6 describes how the ALT uses BGP to propagate Endpoint Identifier reachability over the overlay network. Section 8 describes the construction of the ALT aggregation hierarchy, and Section 9 discusses how LISP+ALT elements are connected to form the overlay Fuller, et al. Expires August 21, 2010 [Page 5] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 network. Fuller, et al. Expires August 21, 2010 [Page 6] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 3. Definition of Terms LISP+ALT operates on two name spaces and introduces a new network element, the LISP+ALT Router (see below). This section provides high-level definitions of the LISP+ALT name spaces, network elements, and message types. Alternative Logical Topology (ALT): The virtual overlay network made up of tunnels between LISP+ALT Routers. The Border Gateway Protocol (BGP) runs between ALT Routers and is used to carry reachability information for EID-prefixes. The ALT provides a way to forward Map-Requests (and, if supported, Data Probes) toward the ETR that "owns" and EID-prefix. As a tunneled overlay, its performance is expected to be quite limited so use of it to forward high-bandwidth flows of Data Probes is strongly discouraged (see Section 4.3 for additional discussion). Legacy Internet: The portion of the Internet which does not run LISP and does not participate in LISP+ALT. ALT Router: The devices which run on the ALT. The ALT is a static network built using tunnels between ALT Routers. These routers are deployed in a roughly-hierarchical mesh in which routers at each level in the topology are responsible for aggregating EID- prefixes learned from those logically "below" them and advertising summary prefixes to those logically "above" them. Prefix learning and propagation between ALT Routers is done using BGP. An ALT Router at the lowest level, or "edge" of the ALT, learns EID- prefixes from its "client" ETRs. See Section 4.1 for a description of how EID-prefixes are learned at the "edge" of the ALT. See also Section 7 for details on how BGP is configured between the different network elements. When an ALT Router receives an ALT Datagram, it looks up the destination EID in its forwarding table (composed of EID prefix routes it learned from neighboring ALT Routers) and forwards it to the logical next-hop on the overlay network. Endpoint ID (EID): A 32-bit (for IPv4) or 128-bit (for ipv6) value used to identify the ultimate source or destination for a LISP- encapsulated packet. See [LISP] for details. EID-prefix: A set of EIDs delegated in a power-of-two block. EID- prefixes are routed on the ALT (not on the global Internet) and are expected to be assigned in a hierarchical manner such that they can be aggregated by ALT Routers. Such a block is characterized by a prefix and a length. Note that while the ALT routing system considers an EID-prefix to be an opaque block of EIDs, an end site may put site-local, topologically-relevant Fuller, et al. Expires August 21, 2010 [Page 7] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 structure (subnetting) into an EID-prefix for intra-site routing. Aggregated EID-prefixes: A set of individual EID-prefixes that have been aggregated in the [RFC4632] sense. Map Server (MS): An edge ALT Router that provides a registration function for non-ALT-connected ETRs, originates EID-prefixes into the ALT on behalf of those ETRs, and forwards Map-Reqeusts to them. See [LISP-MS] for details. Map Resolver (MR): An edge ALT Router that accepts an Encapsulated Map-Reqeust from a non-ALT-connected ITR, decapsulates it, and forwards it on to the ALT toward the ETR which owns the requested EID-prefix. See [LISP-MS] for details. Ingress Tunnel Router (ITR): A router which sends LISP Map- Requests or encapsulates IP datagrams with LISP headers, as defined in [LISP]. In this document, the term refers to any device implementing ITR functionality, including a Proxy-ITR (see [LISP-IW]). Under some circumstances, a LISP Map Resolver may also originate Map-Requests (see [LISP-MS]). Egress Tunnel Router (ETR): A router which sends LISP Map-Replies in response to LISP Map-Requests and decapsulates LISP- encapsulated IP datagrams for delivery to end systems, as defined in [LISP]. In this document, the term refers to any device implementing ETR functionality, including a Proxy-ETR (see [LISP-IW]). Under some circumstances, a LISP Map Server may also respond to Map-Requests (see [LISP-MS]). Routing Locator (RLOC): A routable IP address for a LISP tunnel router (ITR or ETR). Also the output of a EID-to-RLOC mapping lookup; an EID-prefix maps to one or more RLOCs. Typically, RLOCs are numbered from topologically-aggregatable blocks that are assigned to a site at each point to which it attaches to the global Internet; where the topology is defined by the connectivity of provider networks. RLOCs can be thought of as Provider Aggregatable (PA) addresses. Routing for RLOCs is not carried on the ALT. EID-to-RLOC Mapping: A binding between an EID-prefix and the set of RLOCs that can be used to reach it; sometimes referred to simply as a "mapping". EID-prefix Reachability: An EID-prefix is said to be "reachable" if one or more of its locators are reachable. That is, an EID-prefix is reachable if the ETR (or its proxy) that is authoritative for a given EID-to-RLOC mapping is reachable. Fuller, et al. Expires August 21, 2010 [Page 8] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 Default Mapping: A Default Mapping is a mapping entry for EID- prefix 0.0.0.0/0 (0::/0 for ipv6). It maps to a locator-set used for all EIDs in the Internet. If there is a more specific EID- prefix in the mapping cache it overrides the Default Mapping entry. The Default Mapping can be learned by configuration or from a Map-Reply message. ALT Default Route: A EID-prefix value of 0.0.0.0/0 (or 0::/0 for ipv6) which may be learned from the ALT or statically configured on an edge ALT Router. The ALT-Default Route defines a forwarding path for a packet to be sent into the ALT on a router which does not have a full ALT forwarding database. Fuller, et al. Expires August 21, 2010 [Page 9] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 4. The LISP+ALT model The LISP+ALT model uses the same basic query/response protocol that is documented in [LISP]. In particular, LISP+ALT provides two types packet that an ITR can originate to obtain EID-to-RLOC mappings: Map-Request: A Map-Request message is sent into the ALT to request an EID-to-RLOC mapping. The ETR which owns the mapping will respond to the ITR with a Map-Reply message. Since the ALT only forwards on EID destinations, the DA of the Map-Request sent on the ALT MUST be an EID. See [LISP] for the format of Map-Request and Map-Reply packets. Data Probe: Alternatively, an ITR may encapsulate and send the first data packet destined for a EID with no known RLOCs into the ALT as a Data Probe. This might be done minimize packet loss and to probe for the mapping. As above, the authoritative ETR for the EID-prefix will respond to the ITR with a Map-Reply message when it receives the data packet over the ALT. As a side-effect, the encapsulated data packet is delivered to the end-system at the ETR site. Note that the Data Probe the inner Destination Address (DA), which is an EID, is copied to the outer DA and so that the resulting packet can be routed over the ALT. See Section 4.3 for caveats on the usability of Data Probes. The term "ALT Datagram" is short-hand for a Map-Request or Data Probe to be sent into or forwarded on the ALT. Note that while the outer header Source Address of an ALT Datagram is currently expected to be an RLOC, there may be situations (i.e. for experimentation with caching in intermediate ALT nodes) where an EID would be used to force a Map-Reply to be routed back through the ALT. 4.1. Routeability of EIDs A LISP EID has the same syntax as IP address and can be used, unaltered, as the source or destination of an IP datagram. In general, though, EIDs are not routable on the public Internet; LISP+ ALT provides a separate, virtual network, known as the LISP Alternative Logical Topology (ALT) on which a datagram using an EID as a destination address may be transmitted. This network is built as an overlay on the public Internet using tunnels to interconnect ALT Routers. BGP runs over these tunnels to propagate path information needed to forward ALT Datagrams. Importantly, while the ETRs are the source(s) of the unaggregated EID-prefixes, LISP+ALT uses existing BGP mechanisms to aggregate this information. Fuller, et al. Expires August 21, 2010 [Page 10] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 4.1.1. Mechanisms for an ETR to originate EID-prefixes There are three ways that an ETR may originate its mappings into the ALT: 1. By registration with a Map Server as documented in [LISP-MS]. This is the common case and is expected to be used by the majority of ETRs. 2. Using a "static route" on the ALT. Where no Map-Server is available, an edge ALT Router may be configured with a "static EID-prefix route" pointing to an ETR. 3. Edge connection to the ALT. If a site requires fine- grained control over how its EID-prefixes are advertised in to the ALT, it may configure its ETR(s) with tunnel and BGP connections to edge ALT Routers. 4.1.2. Mechanisms for an ITR to forward to EID-prefixes There are three ways that an ITR may send ALT Datagrams: 1. Through a Map Resolver as documented in [LISP-MS]. This is the common case and is expected to be used by the majority of ITRs. 2. Using a "default route". Where a Map Resolver is not available, an ITR may be configured with a static ALT Default Route pointing to an edge ALT Router. 3. Edge connection to the ALT. If a site requires fine-grained knowledge of what prefixes exist on the ALT, it may configure its ITR(s) with tunnel and BGP connections to edge ALT Routers. 4.1.3. Map Server Model preferred The ALT-connected ITR and ETR cases are expected to be rare, as the Map Server/Map Resolver model is both simpler for an ITR/ETR operator to use, and provides a more general service interface to not only the ALT, but also to other mapping databases that may be developed in the future. 4.2. Connectivity to non-LISP sites As stated above, EIDs used as IP addresses by LISP sites are not routable on the public Internet. This implies that, absent a mechanism for communication between LISP and non-LISP sites, connectivity between them is not possible. To resolve this problem, an "interworking" technology has been defined; see [LISP-IW] for Fuller, et al. Expires August 21, 2010 [Page 11] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 details. 4.3. Caveats on the use of Data Probes It is worth noting that there has been a great deal of discussion and controversy about whether Data Probes are a good idea. On the one hand, using them offers a method of avoiding the "first packet drop" problem when an ITR does not have a mapping for a particular EID- prefix. On the other hand, forwarding data packets on the ALT would require that it either be engineered to support relatively high traffic rates, which is not generally feasible for a tunneled network, or that it be carefully designed to aggressively rate-limit traffic to avoid congestion or DoS attacks. There may also be issues caused by different latency or other performance characteristics between the ALT path taken by an initial Data Probe and the "Internet" path taken by subsequent packets on the same flow once a mapping is in place on an ITR. For these and other reasons use of Data Probes should be considered experimental and should be disabled by default in all ITR implementations. Fuller, et al. Expires August 21, 2010 [Page 12] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 5. LISP+ALT: Overview LISP+ALT is a hybrid push/pull architecture. Aggregated EID-prefixes are advertised among the ALT Routers and to those (rare) ITRs that are directly connected via a tunnel and BGP to the ALT. Specific EID-to-RLOC mappings are requested by an ITR (and returned by an ETR) using LISP when it sends a request either via a Map Resolver or to an edge ALT Router. The basic idea embodied in LISP+ALT is to use BGP, running on a tunneled overlay network (the ALT), to establish reachability between ALT Routers. The ALT BGPRoute Information Base (RIB) is comprised of EID-prefixes and associated next hops. ALT Routers interconnect using BGP and propagate EID-prefix updates among themselves. EID- prefix information is learned from ETRs at the "edge" of the ALT either through the use of the Map Server interface (the commmon case), static configuration, or by BGP-speaking ETRs. An ITR use the ALT to learn the best path for forwarding an ALT Datagram destined to a particular EID-prefix. An ITR will normally use a Map Resolver to send its ALT Datagrams on to the ALT but may, in unusual circumstances, use a static ALT Default Route or connect to the ALT using BGP. Note that while this document specifies the use of Generic Routing Encapsulation (GRE) as a tunneling mechanism, there is no reason that parts of the ALT cannot be built using other tunneling technologies, particularly in cases where GRE does not meet security, management, or other operational requirements. References to "GRE tunnel" in later sections of this document should therefore not be taken as prohibiting or precluding the use of other tunneling mechanisms. Note also that two ALT Routers that are directly adjacent (with no layer-3 router hops between them) need not use a tunnel between them; in this case, BGP may be configured across the interfaces that connect to their common subnet and that subnet is then considered to be part of the ALT topology. Use of techniques such as "eBGP multihop" to connect ALT Routers that do not share a tunnel or common subnet is not recommended as the non-ALT Routers in between the ALT Routers in such a configuration may not have information necessary to forward ALT Datagrams destined to EID-prefixes exchanged across that BGP session. In summary, LISP+ALT uses BGP to build paths through ALT Routers so that an ALT Datagram sent in to the ALT can be forwarded to the ETR that holds the EID-to-RLOC mapping for that EID-prefix. This reachability is carried as IPv4 or ipv6 NLRI without modification (since an EID-prefix has the same syntax as IPv4 or ipv6 address prefix). ALT Routers BGP peer with one another, forming the ALT. An Fuller, et al. Expires August 21, 2010 [Page 13] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 ALT Router near the edge learns EID-prefixes originated by authoritative ETRs. This may though the Map Server interface, by static configuration, be via BGP with the ETRs. An ALT Router may also be configured to aggregate EID-prefixes received from ETRs or from other LISP+ALT routers that are topologically "downstream" from it. 5.1. ITR traffic handling When an ITR receives a packet originated by an end system withind its site (i.e. a host for which the ITR is the exit path out of the site) and the destination EID for that packet is not known in the ITR's mapping cache, the ITR creates either a Map-Request for the destination EID or the original packet encapsulated as a Data Probe. The result, known as an ALT Datagram, is then sent to an ALT Router (see also [LISP-MS] for non-ALT-connected ITRs, noting that Data Probes cannot be sent to a Map-Resolver). This "first hop" ALT Router uses EID-prefix routing information learned from other ALT Routers via BGP to guide the packet to the ETR which "owns" the prefix. Upon receipt by the ETR, normal LISP processing occurs: the ETR responds to the ITR with a LISP Map-Reply that lists the RLOCs (and, thus, the ETRs to use) for the EID-prefix. For Data Probes, the ETR also decapsulates the packet and transmits it toward its destination. Upon receipt of the Map-Reply, the ITR installs the RLOC information for a given prefix into a local mapping database. With these mapping entries stored, additional packets destined to the given EID-prefix are routed directly to an RLOC without use of the ALT, until either the entry's TTL has expired, or the ITR can otherwise find no reachable ETR. Note that a valid mapping (not timed-out) may exist that contains no reachable RLOCs (i.e. all paths to that ETR are down); in this case, packets destined to the EID-prefix are dropped. Traffic routed on to the ALT consists solely of ALT Datagrams, i.e. Map-Requests and Data Probes (if supported). 5.2. EID Assignment - Hierarchy and Topology EID-prefixes will be allocated to a LISP site by Internet Registries. Multiple allocations may not be in power-of-2 blocks. But when they are, they will be aggregated into a single, advertised EID-prefix. The ALT network is built in a tree-structured hierarchy to allow aggregation at merge points in the tree. Building such a structure should minimize the number of EID-prefixes carried by LISP+ALT nodes near the top of the hierarchy. Since the ALT does not need in response to changes in policy, Fuller, et al. Expires August 21, 2010 [Page 14] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 subscription, or the underlying physical connectivity, the topology can remain relatively static and aggregation can be sustained. Because routing on the ALT uses BGP, the same rules apply for generating aggregates; in particular, a ALT Router should only be configured to generate an aggregate if it is configured with BGP sessions to all of the originators of components (more-specifics prefixes) of that aggregate. Not all of the components of need to be present for the aggregate to be originated (some may be holes in the covering prefix and some may be down) but the aggregating router must be configured to learn the state of all of the components. As an example, consider ETRs that are originating EID-prefixes for 10.1.0.0/24, 10.1.64.0/24, 10.1.128.0/24, and 10.1.192.0/24. An ALT Router should only be configured to generate an aggregate for 10.1.0.0/16 if it has BGP sessions configured with all of these ETRs, in other words, only if it has sufficient knowledge about the state of those prefixes to summarize them. Under what circumstances the ALT Router actually generates the aggregate is a matter of local policy: in some cases, it will be statically configured to do so at all times with a "static discard" route. In other cases, it may be configured to only generate the aggregate prefix if at least one of the components of the aggregate is learned via BGP. An ALT Router MUST NOT genearte an aggregate that includes a non- LISP-speaking hole unless it can be configured to return a Negative Map-Reply with action="Natively-Forward" (see [LISP]) if it receives an ALT Datagram that matches that hole. If it receives an ALT Datagram that matches a LISP-speaking hole that is currently not reachable, it should return a Negative Map-Reply with action="drop". Negative Map-Replies should be returned with a short TTL, as specified in [LISP-MS]. Note that an off-the-shelf, non-LISP- speaking router configured as an aggregating ALT Router cannot send Negative Map-Replies, so such a router must never originate an aggregate that includes a non-LISP-speaking hole. This implies that two ALT Routers that share an overlapping set of prefixes must exchange those prefixes if either is to generate and export a covering aggregate for those prefixes. It also implies that an ETR which connects to the ALT using BGP must maintain BGP sessions with all of the ALT Routers that are configured to originate an aggregate which covers that prefix. See also [LISP-MS] for an example of other ways that prefix origin consistency and aggregation are maintained. Note: much is currently uncertain about the best way to build the ALT network; as testing and prototype deployment proceeds, a guide to how Fuller, et al. Expires August 21, 2010 [Page 15] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 to best build the ALT network will be developed. 5.3. Use of GRE and BGP between LISP+ALT Routers The ALT network is built using GRE tunnels between ALT Routers. BGP sessions are configured over those tunnels, with each ALT Router acting as a separate AS "hop" in a Path Vector for BGP. For the purposes of LISP+ALT, the AS-path is used solely as a shortest-path determination and loop-avoidance mechanism. Because all next-hops are on tunnel interfaces, no IGP is required to resolve those next- hops to exit interfaces. LISP+ALT's use of GRE and BGP reduces provider Operational Expense (OPEX) because no new protocols need to be either defined or used on the overlay topology. Also, since tunnel IP addresses are local in scope, no coordination is needed for their assignment; any addressing scheme (including private addressing) can be used for tunnel addressing. Fuller, et al. Expires August 21, 2010 [Page 16] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 6. EID-prefix Propagation and Map-Request Forwarding As described in Section 9.2, an ITR sends an ALT Datagram to a given EID-to-RLOC mapping. The ALT provides the infrastructure that allows these requests to reach the authoritative ETR. Note that under normal circumstances Map-Replies are not sent over the ALT - an ETR sends a Map-Reply to the source RLOC learned from the original Map-Request. There may be scenarios, perhaps to encourage caching of EID-to-RLOC mappings by ALT Routers, where Map- Replies could be sent over the ALT or where a "first-hop" ALT router might modify the originating RLOC on a Map-Request received from an ITR to force the Map-Reply to be returned to the "first-hop" ALT Router. These cases will not be supported by initial LISP+ALT implementations but may be subject to future experimentation. ALT Routers propagate path information via BGP ([RFC4271]) that is used by ITRs to send ALT Datagrams toward the appropriate ETR for each EID-prefix. BGP is run on the inter-ALT Router links, and possibly between an edge ("last hop") ALT Router and an ETR or between an edge ("first hop") ALT Router and an ITR. The ALT BGP RIB consists of aggregated EID-prefixes and their next hops toward the authoritative ETR for that EID-prefix. 6.1. Changes to ITR behavior with LISP+ALT As previously described, an ITR will usually use the Map Resolver interface and will send its Map Requests to a Map Resolver. When an ITR instead connects via tunnels and BGP to the ALT, it sends ALT Datagrams to one of its "upstream" ALT Routers; these are sent only to obtain new EID-to-RLOC mappings - RLOC probe and cache TTL refresh Map-Requests are not sent on the ALT. As in basic LISP, it should use one of its RLOCs as the source address of these queries; it should explicitly not use a tunnel interface as the source address as doing so will cause replies to be forwarded over the tunneled topology and may be problematic if the tunnel interface address is not explicitly routed throughout the ALT. If the ITR is running BGP with the LISP+ALT router(s), it selects the appropriate ALT Router based on the BGP information received. If it is not running BGP, it uses a statically-configued ALT Default Route to select an ALT Router. 6.2. Changes to ETR behavior with LISP+ALT As previously described, an ETR will usually use the Map Server interface (see [LISP-MS]) and will register its EID-prefixes with its configured Map Servers. When an ETR instead connects using BGP to one or more ALT Routers, it announces its EID-prefix(es) to those ALT Fuller, et al. Expires August 21, 2010 [Page 17] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 Routers. Note that when an ETR generates a Map-Reply message to return to a querying ITR, it sends it to the ITR's source-RLOC (i.e., on the underlying Internet topology, not on the ALT; this avoids any latency penalty (or "stretch") that might be incurred by routing over the ALT). Fuller, et al. Expires August 21, 2010 [Page 18] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 7. BGP configuration and protocol considerations 7.1. Autonomous System Numbers (ASNs) in LISP+ALT The primary use of BGP today is to define the global Internet routing topology in terms of its participants, known as Autonomous Systems. LISP+ALT specifies the use of BGP to create a global overlay network (the ALT) for finding EID-to-RLOC mappings. While related to the global routing database, the ALT serves a very different purpose and is organized into a very different hierarchy. Because LISP+ALT does use BGP, however, it uses ASNs in the paths that are propagated among ALT Routers. To avoid confusion, it needs to be stressed that that these LISP+ALT ASNs use a new numbering space that is unrelated to the ASNs used by the global routing system. Exactly how this new space will be assigned and managed will be determined during the deployment of LISP+ALT. Note that the ALT Routers that make up the "core" of the ALT will not be associated with any existing core-Internet ASN because the ALT topology is completely separate from, and independent of, the global Internet routing system. 7.2. Sub-Address Family Identifier (SAFI) for LISP+ALT As defined by this document, LISP+ALT may be implemented using BGP without modification. Given the fundamental operational difference between propagating global Internet routing information (the current dominant use of BGP) and creating an overlay network for finding EID- to-RLOC mappings (the use of BGP proposed by this document), it may be desirable to assign a new SAFI [RFC2858] to prevent operational confusion and difficulties, including the inadvertent leaking of information from one domain to the other. At present, this document does not require the assignment of a new SAFI, but the authors anticipate that experimentation may suggest the need for one in the future. Fuller, et al. Expires August 21, 2010 [Page 19] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 8. EID-prefix Aggregation The ALT BGP peering topology should be arranged in a tree-like fashion (with some meshiness), with redundancy to deal with node and link failures. A basic assumption is that as long as the routers are up and running, the underlying Internet will provide alternative routes to maintain BGP connectivity among ALT Routers. Note that, as mentioned in Section 5.2, the use of BGP by LISP+ALT requires that information only be aggregated where all active more- specific prefixes of a generated aggregate prefix are known. This is no different than the way that BGP route aggregation works in the existing global routing system: a service provider only generates an aggregate route if it is configured to learn to all prefixes that make up that aggregate. 8.1. Traffic engineering with LISP and LISP+ALT It is worth noting that LISP+ALT does not directly propagate EID-to- RLOC mappings. What it does is provide a mechanism for an ITR to commonicate with the ETR that holds the mapping for a particular EID- prefix. This distinction is important for several reasons. First, since reachability of RLOCs is learned through the LISP ITR-ETR exchange, "flapping" (frequent BGP updates and withdrawals) is not likely, and mapping information cannot become "stale" due to slow propagation through the ALT BGP mesh. Second, since an ITR learns an EID-to-RLOC mapping directly from the ETR that owns it, it is possible to perform site-to-site traffic engineering by setting the preference and/or weight fields, and by including more-specific EID- to-RLOC information in Map-Reply messages. This is a powerful mechanism that can conceivably replace the traditional practice of routing prefix deaggregation for traffic engineering purposes. Rather than propagating more-specific information into the global routing system for local- or regional- optimization of traffic flows, such more-specific information can be exchanged, through LISP (not LISP+ALT), on an as-needed basis between only those ITRs/ETRs (and, thus, site pairs) that need it. Should a receiving ITR decide that it does not wish to store such more- specific information, it has the option of discarding it as long as a shorter, covering EID-prefix exists. Such an exchange of "more- specifics" between sites facilitates traffic engineering, by allowing richer and more fine-grained policies to be applied without advertising additional prefixes into either the ALT or the global routing system. Fuller, et al. Expires August 21, 2010 [Page 20] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 8.2. Edge aggregation and dampening Note that normal BGP best common practices apply to the ALT network. In particular, first-hop ALT Routers will aggregate EID prefixes and dampen changes to them in the face of excessive updates. Since EID- prefix assignments are not expected to change as frequently as global routing BGP prefix reachability, such dampening should be very rare, and might be worthy of logging as an exceptional event. It is again worth noting that the ALT carries only EID-prefixes, used to construct BGP paths to their owning ETRs; this set of information is considerably less volatile than the actual EID-to-RLOC mappings. Fuller, et al. Expires August 21, 2010 [Page 21] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 9. Connecting sites to the ALT network 9.1. ETRs originating information into the ALT EID-prefix information is originated into the ALT by three different mechanisms: Map Server: In most cases, a site will configure its ETR(s) to register with one or more Map Servers (see [LISP-MS]), and does not participate directly in the ALT. BGP: For a site requiring complex control over their EID-prefix origination into the ALT, an ETR may connect to the LISP+ALT overlay network by running BGP to one or more ALT Router(s) over tunnel(s). The ETR advertises reachability for its EID-prefixes over these BGP connection(s). The edge ALT Router(s) that receive(s) these prefixes then propagate(s) them into the ALT. Here the ETR is simply an BGP peer of ALT Router(s) at the edge of the ALT. Where possible, an ALT Router that receives EID-prefixes from an ETR via BGP should aggregate that information. Configuration: One or more ALT Router(s) may be configured to originate an EID-prefix on behalf of the non-BGP-speaking ETR that is authoritative for a prefix. As in the case above, the ETR is connected to ALT Router(s) using GRE tunnel(s) but rather than BGP being used, the ALT Router(s) are configured with what are in effect "static routes" for the EID-prefixes "owned" by the ETR. The GRE tunnel is used to route Map-Requests to the ETR. Note that the ALT Router could also serve as a proxy for its TCP- connected ETRs. Note: in all cases, an ETR may register to multiple Map Servers or connect to multiple ALT Routers for the following reasons: * redundancy, so that a particular ETR is still reachable even if one path or tunnel is unavailable. * to connect to different parts of the ALT hierarchy if the ETR "owns" multiple EID-to-RLOC mappings for EID-prefixes that cannot be aggregated by the same ALT Router (i.e. are not topologically "close" to each other in the ALT). 9.2. ITRs Using the ALT In the common configuration, an ITR does not need to know anything about the ALT, since it sends Map-Requests to one of its configured Map-Resolvers (see [LISP-MS]). There are two exceptional cases: Fuller, et al. Expires August 21, 2010 [Page 22] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 Static default: If a Map Resolver is not available but an ITR is adjacent to an ALT Router (either over a common subnet or through the use of a tunnel), it can use an ALT Default Route route to cause all ALT Datagrams to be sent that ALT Router. This case is expected to be rare. Connection to ALT: A site with complex Internet connectivity needs may need more fine-grained distinction between traffic to LISP- capable and non-LISP-capable sites. Such a site may configure each of its ITRs to connect directly to the ALT, using a tunnel and BGP connection. In this case, the ITR will receive EID-prefix routes from its BGP connection to the ALT Router and will LISP- encapsulate and send ALT Datagrams through the tunnel to the ALT Router. Traffic to other destinations may be forwarded (without LISP encapsulation) to non-LISP next-hop routers that the ITR knows. In general, an ITR that connects to the ALT does so only to to ALT Routers at the "edge" of the ALT (typically two for redundancy). There may, though, be situations where an ITR would connect to other ALT Routers to receive additional, shorter path information about a portion of the ALT of interest to it. This can be accomplished by establishing GRE tunnels between the ITR and the set of ALT Routers with the additional information. This is a purely local policy issue between the ITR and the ALT Routers in question. As described in [LISP-MS], Map-Resolvers do not accept or forward Data Probes; in the rare scenario that an ITR does support and originate Data Probes, it must do so using one of the exceptional configurations described above. Note that the use of Data Probes is discouraged at this time (see Section 4.3). Fuller, et al. Expires August 21, 2010 [Page 23] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 10. IANA Considerations This document makes no request of the IANA. Fuller, et al. Expires August 21, 2010 [Page 24] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 11. Security Considerations LISP+ALT shares many of the security characteristics of BGP. Its security mechanisms are comprised of existing technologies in wide operational use today, so securing the ALT should be mostly a matter of applying the same technology that is used to secure the BGP-based global routing system (see Section 11.3 below). 11.1. Apparent LISP+ALT Vulnerabilities This section briefly lists the known potential vulnerabilities of LISP+ALT. Mapping Integrity: Can an attacker insert bogus mappings to black- hole (create Denial-of-Service, or DoS attack) or intercept LISP data-plane packets? ALT Router Availability: Can an attacker DoS the ALT Routers connected to a given ETR? If a site's ETR cannot advertise its EID-to-RLOC mappings, the site is essentially unavailable. ITR Mapping/Resources: Can an attacker force an ITR or ALT Router to drop legitimate mapping requests by flooding it with random destinations for which it will generate large numbers of Map- Reqeusts and fill its mapping cache? Further study is required to see the impact of admission control on the overlay network. EID Map-Request Exploits for Reconnaissance: Can an attacker learn about a LISP site's TE policy by sending legitimate mapping requests and then observing the RLOC mapping replies? Is this information useful in attacking or subverting peer relationships? Note that any public LISP mapping database will have similar data- plane reconnaissance issue. Scaling of ALT Router Resources: Paths through the ALT may be of lesser bandwidth than more "direct" paths; this may make them more prone to high-volume denial-of-service attacks. For this reason, all components of the ALT (ETRs and ALT Routers) should be prepared to rate-limit traffic (ALT Datagrams) that could be received across the ALT. UDP Map-Reply from ETR: Since Map-Replies are sent directly from the ETR to the ITR's RLOC, the ITR's RLOC may be vulnerable to various types of DoS attacks (this is a general property of LISP, not an LISP+ALT vulnerability). Fuller, et al. Expires August 21, 2010 [Page 25] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 11.2. Survey of LISP+ALT Security Mechanisms Explicit peering: The devices themselves can both prioritize incoming packets, as well as potentially do key checks in hardware to protect the control plane. Use of TCP to connect elements: This makes it difficult for third parties to inject packets. Use of HMAC Protected BGP/TCP Connections: HMAC is used to verify message integrity and authenticity, making it nearly impossible for third party devices to either insert or modify messages. Message Sequence Numbers and Nonce Values in Messages: This allows an ITR to verify that the Map-Reply from an ETR is in response to a Map-Request originated by that ITR (this is a general property of LISP; LISP+ALT does not change this behavior). 11.3. Use of new IETF standard BGP Security mechanisms LISP+ALT's use of BGP allows the ALT to take advantage of BGP security features designed for existing Internet BGP use. For example, should either sBGP [I-D.murphy-bgp-secr] or soBGP [I-D.white-sobgparchitecture] become widely deployed it expected that LISP+ALT could use these mechanisms to provide authentication of EID- to-RLOC mappings, and EID origination. Fuller, et al. Expires August 21, 2010 [Page 26] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 12. Acknowledgments The authors would like to specially thank J. Noel Chiappa who was a key contributer to the design of the LISP-CONS mapping database (many ideas from which made their way into LISP+ALT) and who has continued to provide invaluable insight as the LISP effort has evolved. Others who have provided valuable contributions include John Zwiebel, Hannu Flinck, Amit Jain, and Scott Brim. Fuller, et al. Expires August 21, 2010 [Page 27] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 13. References 13.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, March 2000. [RFC2858] Bates, T., Rekhter, Y., Chandra, R., and D. Katz, "Multiprotocol Extensions for BGP-4", RFC 2858, June 2000. [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan", BCP 122, RFC 4632, August 2006. 13.2. Informative References [I-D.murphy-bgp-secr] Murphy, S., "BGP Security Analysis", draft-murphy-bgp-secr-04 (work in progress), November 2001. [I-D.white-sobgparchitecture] White, R., "Architecture and Deployment Considerations for Secure Origin BGP (soBGP)", draft-white-sobgparchitecture-00 (work in progress), May 2004. [LISP] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "Locator/ID Separation Protocol (LISP)", draft-ietf-lisp-06.txt (work in progress), January 2010. [LISP-IW] Lewis, D., Meyer, D., Farinacci, D., and V. Fuller, "Interworking LISP with IPv4 and ipv6", draft-ietf-lisp-interworking-01.txt (work in progress), January 2010. [LISP-MS] Fuller, V. and D. Farinacci, "LISP Map Server", draft-ietf-lisp-ms-04.txt (work in progress), October 2009. Fuller, et al. Expires August 21, 2010 [Page 28] Internet-Draft LISP Alternative Topology (LISP+ALT) February 2010 Authors' Addresses Vince Fuller Cisco Tasman Drive San Jose, CA 95134 USA Email: vaf@cisco.com Dino Farinacci Cisco Tasman Drive San Jose, CA 95134 USA Email: dino@cisco.com Dave Meyer Cisco Tasman Drive San Jose, CA 95134 USA Email: dmm@cisco.com Darrel Lewis Cisco Tasman Drive San Jose, CA 95134 USA Email: darlewis@cisco.com Fuller, et al. Expires August 21, 2010 [Page 29] --A6N2fC+uXW/VQSAv-- From job@instituut.net Fri Feb 26 03:21:25 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id E9BC93A876F for ; Fri, 26 Feb 2010 03:21:25 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -0.437 X-Spam-Level: X-Spam-Status: No, score=-0.437 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, FH_RELAY_NODNS=1.451, HELO_MISMATCH_NET=0.611, RDNS_NONE=0.1] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id OVANC+sUIUda for ; Fri, 26 Feb 2010 03:21:24 -0800 (PST) Received: from masteen.6core.net (unknown [212.19.216.212]) by core3.amsl.com (Postfix) with ESMTP id CAF1E3A8770 for ; Fri, 26 Feb 2010 03:21:20 -0800 (PST) Received: from feanor.lan (ip545039af.adsl-surfen.hetnet.nl [84.80.57.175]) by masteen.6core.net (Postfix) with ESMTPSA id E2DCA102005F; Fri, 26 Feb 2010 12:27:44 +0100 (CET) From: "Job W. J. Snijders" Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Date: Fri, 26 Feb 2010 12:23:32 +0100 Message-Id: To: lisp@ietf.org Mime-Version: 1.0 (Apple Message framework v1077) X-Mailer: Apple Mail (2.1077) Cc: lisp-ops@external.cisco.com Subject: [lisp] Anycast PETR range for interworking X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Feb 2010 11:21:26 -0000 Dear Fellow LISPers, I quote from the interworking-01 draft "Proxy Egress Tunnel Routers = (PETRs) allow for LISP-NR sites to communicate with non-LISP sites in the case = where the access network does not allow for the LISP-NR site send packets with = the source address of the site's EID(s)."=20 The two main reasons for using a PETR:=20 - "Avoiding strict uRPF failures - Some provider's access = network require=20 the source of the packets emitted to be within the addressing = scope of the access networks." - "Traversing a different IP Protocol - A LISP site may want to = transmit packets to a non-LISP site where the some of the intermediate = network does not support an IP protocol (v4 or v6)." Currently there are a handful PETR devices that I know of, which all = have different IP addresses. To me it seems that the PETR devices could use = IP addresses that are anycasted to the internet in a similar way the 6to4 = prefix is anycasted. This would allow for ease of configuration on LISP-NR = sites and would serve as a service to the public.=20 I want to propose to RIPE to assign a IPv4 /24 and an IPv6 equivalent = for "Experimental Purposes"[1] to us (the current testbed). Requesting PI or = PA space dedicated for this purpose does not seem applicable because of = various reasons. The advantage of "experimental ranges" is that because of their temporary nature RIPE will be less strict compared to 'normal' = requirements: within these ranges we can only account for 1 IPv4 /32 and 1 IPv6 /128.=20= I already have a sponsoring LIR[2], and through my sponsor I will = announce this prefix in europe, and would encourage other people that have PETR = capable devices to start using this prefix too, thus increasing the PETR = capacity and making the mechanism more resilient. Also I can take the lead in = documenting the experiment and and making sure we adhere RIPE policies.=20 If the experiment succeeds we want to move forward, I guess we should = write a draft explaining and defending the need for a "Special Purpose" prefix, similar to RFC 3068, in addition to the interworking draft.=20 Any thoughts on the subject would be appreciated very much! If the list supports me I will contact RIPE and start the paperwork.=20 Kind regards, Job Snijders [1] http://www.ripe.net/docs/ripe-389.html [2] InTouch NV, Amsterdam, http://www.intouch.eu/ From hartmans@mit.edu Fri Feb 26 04:14:27 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 8032B3A877B for ; Fri, 26 Feb 2010 04:14:27 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -2.657 X-Spam-Level: X-Spam-Status: No, score=-2.657 tagged_above=-999 required=5 tests=[AWL=-0.392, BAYES_00=-2.599, IP_NOT_FRIENDLY=0.334] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id GIyD66Jnk6VZ for ; Fri, 26 Feb 2010 04:14:26 -0800 (PST) Received: from mail.suchdamage.org (permutation-city.suchdamage.org [69.25.196.28]) by core3.amsl.com (Postfix) with ESMTP id 598703A7B89 for ; Fri, 26 Feb 2010 04:14:26 -0800 (PST) Received: from carter-zimmerman.suchdamage.org (carter-zimmerman.suchdamage.org [69.25.196.178]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "laptop", Issuer "laptop" (not verified)) by mail.suchdamage.org (Postfix) with ESMTPS id 6A6FB201B2; Fri, 26 Feb 2010 07:16:40 -0500 (EST) Received: by carter-zimmerman.suchdamage.org (Postfix, from userid 8042) id 532779C3DE; Fri, 26 Feb 2010 07:16:37 -0500 (EST) From: Sam Hartman To: "Job W. J. Snijders" References: Date: Fri, 26 Feb 2010 07:16:37 -0500 In-Reply-To: (Job W. J. Snijders's message of "Fri, 26 Feb 2010 12:23:32 +0100") Message-ID: User-Agent: Gnus/5.110009 (No Gnus v0.9) Emacs/22.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: lisp@ietf.org, lisp-ops@external.cisco.com Subject: Re: [lisp] Anycast PETR range for interworking X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Feb 2010 12:14:27 -0000 >>>>> "Job" == Job W J Snijders writes: Job> which all have different IP addresses. To me it seems that the Job> PETR devices could use IP addresses that are anycasted to the Job> internet in a similar way the 6to4 prefix is anycasted. This As Robbin and I have discussed, we believe that PETR devices need some for of authentication and access control between the PETR and ITR. This is needed to avoid the PETR being used to assist in address spoofing attacks. So, while anycast may be useful, I don't think it will be nearly as useful as say for 6to4. From jnc@mercury.lcs.mit.edu Fri Feb 26 13:56:02 2010 Return-Path: X-Original-To: lisp@core3.amsl.com Delivered-To: lisp@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id B88EC28C333 for ; Fri, 26 Feb 2010 13:56:02 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -6.484 X-Spam-Level: X-Spam-Status: No, score=-6.484 tagged_above=-999 required=5 tests=[AWL=0.115, BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id xVrNd-yzWUGM for ; Fri, 26 Feb 2010 13:56:02 -0800 (PST) Received: from mercury.lcs.mit.edu (mercury.lcs.mit.edu [18.26.0.122]) by core3.amsl.com (Postfix) with ESMTP id 017143A8855 for ; Fri, 26 Feb 2010 13:56:01 -0800 (PST) Received: by mercury.lcs.mit.edu (Postfix, from userid 11178) id 3FCED6BE5DA; Fri, 26 Feb 2010 16:58:17 -0500 (EST) To: lisp@ietf.org Message-Id: <20100226215817.3FCED6BE5DA@mercury.lcs.mit.edu> Date: Fri, 26 Feb 2010 16:58:17 -0500 (EST) From: jnc@mercury.lcs.mit.edu (Noel Chiappa) Cc: jnc@mercury.lcs.mit.edu Subject: Re: [lisp] Anycast PETR range for interworking X-BeenThere: lisp@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List for the discussion of the Locator/ID Separation Protocol List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Feb 2010 21:56:02 -0000 > From: Sam Hartman > we believe that PETR devices need some for of authentication and access > control between the PETR and ITR. This is needed to avoid the PETR > being used to assist in address spoofing attacks. There has been some offline dicussion about the need to be able to track back LISP traffic, e.g. to find the source of DoS attacks - and in particular, to deal with cases of address spoofing. (Bear in mind that the source of the DoS might be a machine which is pwned, so simply refusing traffic from Cracker-Site-ITR is not a protection from DoS.) > So, while anycast may be useful, I don't think it will be nearly as > useful as say for 6to4. If we had better unwanted-traffic tracking/control, it might be useful. In particular, it might avoid path stretch. But it's too early to say for sure; sounds like an idea to keep in the back of the mind for future evaluation, though. Noel