Subject: [rohc] WG last-call for SIP/SigComp

From: "Lars-Erik Jonsson \(LU/EAB\)" <[email-masked]>
Date: Fri, 13 Oct 2006 15:40:09 +0200

Soon after the publication of SigComp (RFC 3320), work with
a document defining the specifics of using SigComp for SIP
message compression was initialised. For various reasons, the
finalisation of this document has taken much more time than
anticipated, but me and the authors now believe it should be
ready for publication. This is an essential document for the
application of SigComp on SIP, and it is thus important that
we finally get it out of the pipe. We are therefore now
issuing a working group last-call on the following document:
 
             draft-ietf-rohc-sigcomp-sip-03.txt
                  (for publication as Proposed Standard)
 
This will be the usual two-week WG last-call as suggested in
RFC 2418. Please direct last-call comments to the ROHC mailing
list [email-masked] before Fri, 2006-10-27, 18:00 UTC.
 
/L-E

--------------------------------------
Lars-Erik Jonsson
IETF ROHC WG Chair
E-mail: [email-masked]
Phone: +46 8 404 29 61

My opinions are my personal opinions and should not be considered
as the opinions of my employer, if not explicitly stated.

_______________________________________________
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---

From: Pekka Pessi <[email-masked]>
Date: Wed, 18 Oct 2006 16:49:14 +0300

"Lars-Erik Jonsson (LU/EAB)" <[email-masked]>
writes:
>ready for publication. 

Unlike the earliear versions the new dfart modifies the SIP
protocol itself. In my opinion, the -03 is such a modification to
SIP that it should be processed by SIP WG according to the BCP 67.

Also, the new draft breaks the backwards-compatibility with
rfc3486-compliant implementations. It would be doubleplusgood if
the breakage was indicated by rfc3486-compatible mechanisms, like
comp=sigcomp1 SIP URI/Via header parameter. The new sigcomp-id
parameters could replace the old ones, too.

I doubt that resubmitting the draft as rfc3486-bis on SIP WG
charter would impose much additional delay for this already way
too long delayed spec. For example, there is now a normative
reference to the still very much alive sip outbound draft in the
spec.

As an added bonus of redirecting the work to SIP WG where it
belongs the ROHC WG would be able to clean its table and get rid
of all the people from Phone Companies. Hm?

>This is an essential document for the
>we finally get it out of the pipe. 

In any case, after a quick peek to the resurrected -03 I found 
quite a few issues that I would like to be addressed before
submitting the draft to IESG:
- how to map a large (>64 K or even smaller) SIP message to
  SigComp messages
  - ...and how to do that on SCTP
- how to handle SIP-level retransmissions
- document could discuss using STUN or other protocols on a single
  connection/port in addition to SIP and SigComp
- the brand new mechanisms for compartment handling, including
  ABNF and examples in section 6 are contradictory, full of errors
  and they are just plain confusing. I'll provide detailed
  proposals for corrections later.
- the example in section 10 does not address scenario where
  the original UAC would become UAS (that is, the role of the
  server and client would reverse)
- the example section should include a flow or flows with 1)
  outbound and 2) gruu and 3) a NAT between user-agent and its
  outbound proxy

--Pekka