Subject: [Sip] I-D ACTION:draft-rosenberg-rohc-sip-udpcomp-00.txt

From: [email-masked]
Date: Wed, 18 Jul 2001 06:58:38 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title		: Compression of SIP
	Author(s)	: J. Rosenberg
	Filename	: draft-rosenberg-rohc-sip-udpcomp-00.txt
	Pages		: 12
	Date		: 17-Jul-01
	
The Session Initiation Protocol (SIP), along with many other IP
protocols used for multimedia communications, are UDP-based, textual
protocols engineered for bandwidth rich links. As a result, these
messages have not been optimized for message size. With the planned
usage of these protocols in wireless handsets as part of 2.5G and 3G
wireless, the large size of these messages is problematic, primarily
for latency reasons. As a result, we propose a protocol shim between
SIP (or any other UDP based protocol meeting our requirements) and
UDP in order to efficiently compress SIP messages. Preliminary
results have shown compression gains of up to 8:1.

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From: Romeo Zwart <[email-masked]>
Date: Thu, 19 Jul 2001 21:27:18 +0200

Jonathan,

In the diagram of section 4.6, the WRITE HIGH REFERENCE token is shown as 
identical to the WRITE HIGH token. I assume this is a typo. What is the 
intended token for the WRITE HIGH REFERENCE case?

In the same diagram, is there a defined value for the three 'padding' bits 
that fill up the third octet?

In section 5 you describe your proposed new LZW variant. Your 'friendly 
test' shows very nice results, except for the initial message in the 
series, which has an (expected) larger compressed size than the 
uncompressed size. Have you considered jumpstarting the codebook with a set 
of default entries (e.g. INVITE, From:, To:, etc.)? Would you expect 
earlier convergence?

Romeo

At 12:58 PM 7/18/2001, [email-masked] wrote:
>Content-Type: text/plain
>Content-ID:     <[email-masked]>

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