Subject: [MOBILE-IP] New (and I think final) Mobile IPv6 draft submitted

From: Dave Johnson <[email-masked]>
Date: Thu, 10 Feb 2000 23:09:55 -0500

This afternoon, I submitted a new version of the Mobile IPv6 draft
that I think includes fixes for all of the comments I've received on
earlier versions of the draft, including several places where changes
or clarifications were needed to get along properly with IPsec.  Here
is the list of major changes since the previous version of the draft:

  -  Added additional material in Section 10.2, discussing use any
     automated key management protocol [13] (such as IKE [8]) to
     create any new SA (or SA bundle) while away from home.

  -  Also added additional material in Section 10.2 to define the
     order in which the Home Address option and Binding Update option
     appear in the packet relative to the AH or ESP header that is
     required when a Binding Update is inserted.  In addition, this
     change corrects the placement of the Home Address option in the
     packet to be before (not after) the AH or ESP header, so that the
     Home Address option is processed by the destination node before
     the AH or ESP header is processed.

  -  Changed the dynamic home agent address discovery mechanism
     to use dedicated ICMP message types (defined in Sections 5.6
     and 5.7) rather than (re)using the Binding Update and Binding
     Acknowledgement options.  This change was primarily motivated
     by the fact that IP packets sent to an anycast address cannot
     (currently) use AH or ESP authentication since the packet is not
     directed to any single node with which a Security Association
     could be established.  In addition, this change simplifies the
     processing of Binding Updates and Binding Acknowledgements, since
     it removes the special cases there for dynamic home agent address
     discovery.

  -  Removed the Binding Acknowledgement option Status value of 135
     (dynamic home agent address discovery response) since it is
     no longer needed with the revised dynamic home agent address
     discovery mechanism.

  -  Removed the Home Agents List Sub-Option since it is no longer
     needed with the revised dynamic home agent address discovery
     mechanism.

  -  Added a Duplicate Address Detection (D) bit in the Binding
     Update option format, to request the mobile node's home agent to
     perform Duplicate Address Detection on the mobile node's home
     link for the home address in this binding.  Also defined a new
     Status value of 138 (Duplicate Address Detection failed) for
     the Binding Acknowledgement, to indicate any failure of this
     Duplicate Address Detection on the home link.  The addition of
     the Duplicate Address Detection (D) bit in the Binding Update
     option also reduced the Reserved field from a 5-bit field to a
     4-bit field (and caused it to be renamed Reservd so that the
     label fits in the packet format drawing).

  -  Added text in Section 9.3 and 10.16 to describe the use of the
     new Duplicate Address Detection (D) bit in the Binding Update
     option format.

  -  Changed the description of the Home Agents List conceptual data
     structure to require maintenance of a Home Agents List by each
     mobile node, as well as by each home agent.  A mobile node uses
     this list to enable notifying a home agent on its previous link,
     when the mobile node moves to a new link.

  -  In Section 10.10, changed the procedure for retransmitting
     Binding Updates to require that the Sequence Number field in
     each successive retransmission MUST be greater than that used
     in the previous transmission.  The draft previously incorrectly
     specified here that the same sequence number must be used for
     each retransmission.  The change is needed since such reuse
     of sequence numbers will fail if the original transmission
     of the Binding Update was in fact received, but the Binding
     Acknowledgement (instead of the Binding Update) was lost in
     transmission on the network.  Changing the Sequence Number on
     each retransmission also avoids the any acknowledgement ambiguity
     problem, making the start time for the binding lifetime more
     clear.

  -  Corrected yet a few more minor typographical errors in places.

I think (and hope :-) that this version of the draft will be the final
version before going to Proposed Standard.  We plan to start a Last
Call on the draft once the official announcement of this new version
comes out on the IETF-Announce mailing list.  For those who would like
to get a copy of the new version now while we wait for the official
announcement, it is available on the CMU Monarch Project web pages at

http://www.monarch.cs.cmu.edu/internet-drafts/draft-ietf-mobileip-ipv6-10.txt

If you have any comments on this new version, please let me know.
Comments are best sent to the Mobile IP mailing list at
[email-masked].

                                        Dave

--
David B. Johnson                         [email-masked]
Associate Professor                      http://www.cs.cmu.edu/~dbj/
Computer Science Department              http://www.monarch.cs.cmu.edu/
Carnegie Mellon University               Phone: (412) 268-7399
5000 Forbes Avenue                       Fax: (412) 268-5576
Pittsburgh, PA  15213-3891

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From: [email-masked]
Date: Fri, 11 Feb 2000 13:50:04 +0900

>     the AH or ESP header is processed.

        If home address option (or any of option that need authenticity)
        appear prior to ESP header, we need to mandate use of AH for
        these packets.  ESP does not protect packet portion before ESP header.

        There are many "AH or ESP" in document, I'm not sure which one (or
        all of them) need clarification.

itojun

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From: Erik Nordmark <[email-masked]>
Date: Thu, 10 Feb 2000 23:03:47 -0800

>      link for the home address in this binding.

Does this imply that if the D bit is set the home agent will wait
for a few seconds to do DAD i.e. the update ack will be delayed?
Or is the home agent allowed to retain state to the effect "I did
DAD for this address 10 minutes ago" to reduce the number of times
DAD will occur?

>      when the mobile node moves to a new link.

The above description reads as if a MN has a home agent per link...

Did you mean "notifying a previous default router which might be
used as a home agent for smoother handoff"?

   Erik