Subject: RFC 2461-new issue?

From: Suresh Krishnan <[email-masked]>
Date: Thu, 23 Oct 2003 14:40:00 -0400 (EDT)

Hi,
  In section 4.2 of RFC 2461 regarding the RA message format the following 
is mentioned

     Reserved       A 6-bit unused field.  It MUST be initialized to
                     zero by the sender and MUST be ignored by the
                     receiver.

The mobile-ipv6 draft draft-ietf-mobileip-ipv6-24.txt mandates using the 
most significant bit of this field as a home agent bit(will be set to 1 if 
the router is also a MIPv6 HA on this link). I do not know what is the 
best way to solve this apparent contradiction. I see the following 
possible solutions (in no particular order)

* Reduce the reserved field length in RFC2461bis to 5 bits
* Change the MUSTs to SHOULDs in RFC2461bis
* Put a note on RFC2461/RFC2461bis in the rfc-index saying it has been 
updated by the MIPv6 RFC(when it comes out)

Regards
Suresh

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From: Soliman Hesham <[email-masked]>
Date: Thu, 23 Oct 2003 22:21:49 -0400

> possible solutions (in no particular order)

=> I don't think there is a contradiction. Any IETF
spec can be extended by another spec. The question is
whether we want to include all these extensions in the 
new ND spec. I have no problem with that, but I see a couple 
of issues:

1. New extensions are bound to happen anyway and people
will implement them as they come. So the ND spec is likely
to not always include all extensions.
2. This RFC is in DS status and my understanding is that
there is a limit on the new features that can be included, 
especially if they come from less mature specifications. 

If (2) above is incorrect then there is no problem with
adding new features. 

Hesham

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From: "Bound, Jim" <[email-masked]>
Date: Thu, 23 Oct 2003 23:42:44 -0400

My view is we are updating 2461 to remain DS and not breaking any
architectural components  as that would require and appeal once a spec
is at DS which this one is.  So idea is to update the spec for
clarification, correctness, or extensions.

> * Reduce the reserved field length in RFC2461bis to 5 bits

This is the correct answer IMO.

/jim