[rohc] sigcomp-sip: David Ward's DISCUSS
Carsten Bormann <cabo@tzi.org> Wed, 18 July 2007 07:13 UTC
Return-path: <rohc-bounces@ietf.org>
Received: from [127.0.0.1] (helo=stiedprmman1.va.neustar.com) by megatron.ietf.org with esmtp (Exim 4.43) id 1IB3ie-0005TE-Rw; Wed, 18 Jul 2007 03:13:08 -0400
Received: from [10.90.34.44] (helo=chiedprmail1.ietf.org) by megatron.ietf.org with esmtp (Exim 4.43) id 1IB3id-0005T7-8u for rohc@ietf.org; Wed, 18 Jul 2007 03:13:07 -0400
Received: from mailhost.informatik.uni-bremen.de ([134.102.201.18] helo=informatik.uni-bremen.de) by chiedprmail1.ietf.org with esmtp (Exim 4.43) id 1IB3ib-0006sM-OW for rohc@ietf.org; Wed, 18 Jul 2007 03:13:07 -0400
Received: from [127.0.0.1] (maildrop [134.102.201.19]) by informatik.uni-bremen.de (8.14.0/8.14.0) with ESMTP id l6I7D0oE011491; Wed, 18 Jul 2007 09:13:00 +0200 (CEST)
Mime-Version: 1.0 (Apple Message framework v752.3)
Content-Type: text/plain; charset="US-ASCII"; delsp="yes"; format="flowed"
Message-Id: <5B7B53E7-6BB4-4240-8DB5-1088C102D357@tzi.org>
Content-Transfer-Encoding: 7bit
From: Carsten Bormann <cabo@tzi.org>
Date: Wed, 18 Jul 2007 09:12:57 +0200
To: rohc@ietf.org
X-Mailer: Apple Mail (2.752.3)
X-Virus-Scanned: by amavisd-new
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 5a9a1bd6c2d06a21d748b7d0070ddcb8
Cc: Carsten Bormann <cabo@tzi.org>, dward@cisco.com
Subject: [rohc] sigcomp-sip: David Ward's DISCUSS
X-BeenThere: rohc@ietf.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Robust Header Compression <rohc.ietf.org>
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/rohc>, <mailto:rohc-request@ietf.org?subject=unsubscribe>
List-Post: <mailto:rohc@ietf.org>
List-Help: <mailto:rohc-request@ietf.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/rohc>, <mailto:rohc-request@ietf.org?subject=subscribe>
Errors-To: rohc-bounces@ietf.org
ROHCers, David Ward, RTG AD, has put in a DISCUSS on draft-ietf-rohc-sigcomp- sip-07.txt, which reads: > 3320 section 8.7 (Decompression failures) > > "If a decompression failure occurs when decompressing a message then > the UDVM informs the dispatcher and takes no further action. It is > the responsibility of the dispatcher to decide how to cope with the > decompression failure. In general a dispatcher SHOULD discard the > compressed message (or the compressed stream if the transport is > stream-based) and any decompressed data that has been outputted but > not yet passed to the application. > " > > and in this draft there is no mention of how SIP should handle > decompression failures From my point of view (having been involved in this from day 1), this is nicely covered by section 8: > 8. SIP Retransmissions > > When SIP messages are retransmitted, they need to be re-compressed, > taking into account any SigComp states that may have been > created or > invalidated since the previous transmission. Implementations MUST > NOT cache the result of compressing the message and retransmit > such a > cached result. > > The reason for this behavior is that it is impossible to know > whether > the failure causing the retransmission occurred on the message > being > retransmitted or on the response to that message. If the response > was lost, any state changes effected by the first instance of the > retransmitted message would already have taken place. If these > state > changes removed a state that the previously-transmitted message > relied upon, then retransmission of the same compressed message > would > lead to a decompression failure. However, this may be a bit opaque to people new to this set of documents. Also, the discussion of NACK in the draft only relates to SigComp state; it could mention that NACK (now being mandatory) is the general way to handle decompression failure. All of this is editorial, I think, but I also think it would be nice not to entirely rely on the reader making the connections. Any opinions? I could go ahead and draft some text. Gruesse, Carsten _______________________________________________ Rohc mailing list Rohc@ietf.org https://www1.ietf.org/mailman/listinfo/rohc
- [rohc] sigcomp-sip: David Ward's DISCUSS Carsten Bormann
- Re: [rohc] sigcomp-sip: David Ward's DISCUSS Lars-Erik Jonsson
- Re: [rohc] sigcomp-sip: David Ward's DISCUSS David Ward