Subject: RE: [Mip4] I-D ACTION:draft-ietf-mip4-rfc3344bis-03.txt

From: "Kent Leung \(kleung\)" <[email-masked]>
Date: Wed, 14 Mar 2007 01:48:33 -0700

Now I remember why the section seems wrong to me.  The index to the
pending registration request is based on home address and ID if home
address is non-zero.  And in accordance to RFC 2794, index is based on
NAI and ID when home address is zero.

But when multiple MNs with different NAIs registers with same non-zero
home address and ID, this logic cannot discern the mapping of reply to
request because the home address is copied from the RRQ to the RRP.  The
statement below will find a RRQ that may not correspond to the RRP for
the same MN.

   "When a foreign agent receives a Registration Reply message, it MUST
   search its visitor list for a pending Registration Request with the
   same mobile node home address as indicated in the Reply. (...)
   The foreign agent MUST also silently
   discard the Reply if the low-order 32 bits of the Identification
   field in the Reply do not match those in the Request."

So going back to what I said, "It would be unambiguous if FA can map the
reply to the request based on the NAI and ID field when NAI extension
was in the registration request."  This is different in the sense that
the index is always based on NAI and ID if the NAI extension is in the
RRQ.

Suggested text for 3.7.3.1:

   When a foreign agent receives a Registration Reply message, it MUST
   search its visitor list for a pending Registration Request that
   corresponds to the Reply.  If the NAI extension is present in the
   Registration Reply, then the mobile node is identified
   by the NAI instead of the home address.  The foreign agent
   looks up the pending Request that matches the mobile node identifier.
   If the Registration Reply does not correspond with any pending 
   Registration Request, the foreign agent MUST
   silently discard the Reply.  The foreign agent MUST also silently
   discard the Reply if the low-order 32 bits of the Identification
   field in the Reply do not match those in the Request.

Suggested text for 3.7.1:

   If there is an NAI extension in the Registration Request
   message, then the foreign agent MUST follow the procedures specified
   in RFC 2794 [2].  In particular, if the foreign agent cannot manage
   pending registration request records with NAI
   for the mobile node, the foreign agent MUST return a Registration
   Reply with Code indicating NONZERO_HOMEADDR_REQD (see [2]).

This assumes that 2794bis addresses NAI/nonzero HoA case.

Hope I'm making sense as it's getting late..

Kent

-----Original Message-----
From: Kent Leung (kleung) 
Sent: Wednesday, March 14, 2007 12:22 AM
To: 'Ahmad Muhanna'; [email-masked]
Subject: RE: [Mip4] I-D ACTION:draft-ietf-mip4-rfc3344bis-03.txt

Hi Ahmad.  I agree that it's OK, my oversight on "see section 3.7.1" and
assumption that the reply must be discarded.  Thanks.

Kent

-----Original Message-----
From: Ahmad Muhanna [mailto:[email-masked]]
Sent: Tuesday, March 13, 2007 9:11 PM
To: Kent Leung (kleung); [email-masked]
Subject: RE: [Mip4] I-D ACTION:draft-ietf-mip4-rfc3344bis-03.txt

Hi Kent,

In the same section you mentioned 3.7.3.1., I think the text already
covers what you are requesting and I do not see any ambiguity. Here is
the excerpt:

"
   When a foreign agent receives a Registration Reply message, it MUST
   search its visitor list for a pending Registration Request with the
   same mobile node home address as indicated in the Reply.  If no such
   pending Request is found, and if the Registration Reply does not
   correspond with any pending Registration Request with a zero mobile
   node home address (see section 3.7.1), the foreign agent MUST
   silently discard the Reply.  The foreign agent MUST also silently
   discard the Reply if the low-order 32 bits of the Identification
   field in the Reply do not match those in the Request.
"

I think the key text here is "... , and if the Registration Reply does
not correspond with any pending Registration Request with a zero mobile
node home address (see section 3.7.1) ....."

And since section 3.7.1. refers to RFC2794 which address the
identification of a user/MN using NAI while the Home address field of
zero. I believe the text already covers what you are looking for. No?

Regards,
Ahmad

-- 
Mip4 mailing list: [email-masked]
    Web interface: https://www1.ietf.org/mailman/listinfo/mip4
     Charter page: http://www.ietf.org/html.charters/mip4-charter.html
Supplemental site: http://www.mip4.org/