Subject: [Simple] IM format

From: "Petri K. Koskelainen" <[email-masked]>
Date: Fri, 12 Oct 2001 13:51:12 -0400 (EDT)

Hi,

Message and thread identification is essential for 
session based IM format as described in 
"Group Messaging in SIP" draft.

Thread identification is not very useful in two-party chat,
but in multi-party chat (and some non-chat applicatios)
it is a necessity.

Thread-id header itself is not needed. 
Instead, thread identification can be achieved 
with Message-id and References headers.
It allows also nested threads.

We also need (optional) Subject header since the subject may
change inside a chat session (e.g. new sub-thread).

Message-id and References headers may be added into SIP format 
or into new (SIP/CPIM like) IM format. 
The amount of headers needed for IM format seems to be
relative high and finalizing the new format will be 
time-consuming. Also, given that SIP compression eliminates
the overhead in low-speed links there isn't any reason
trying to invent new IM format (just to save 2-3 transport related
headers).

--
Petri