Subject: RE: [Simple] IM over the signaling connection

From: [email-masked]
Date: Thu, 11 Oct 2001 16:17:52 -0500

>> Jonathan R. Wrote:
>>
>> Adding some kind of correlation ID to the message meta-data is the
simplest
>> way. For sessions, its right there with the other headers, for page
mode, it
>> could be a SIP header, or a meta-data header like the CPIM headers are.

Providing messages with two optional headers: <Message-ID> and <Thread-ID>
allows the sender to choose to

(1) provide message identification for later processing (if this is not
clear then imagine some message indexing at the server to allow message
access by non-SIP elements, like web-browsers via an App Server, WAP etc)

and

(2) to associate a specific message with a thread-of-messages - this way
if a message arrives using page mode, and a later session is established
and a new message arrives with the same Thread-ID, the UA knows it is part
of the same session - this also allows muxing multiple threads within a
session without any transport muxing.

(of course both IDs are generated by the originating UA, the two headers
should
be optional - many apps do not need them).

- gur

Gur Kimchi
Chief Architect
VocalTec Communications.

---

From: Paul Kyzivat <[email-masked]>
Date: Thu, 11 Oct 2001 19:28:37 -0400

In addition to <Message-ID> and <Thread-ID>, it would be useful to have
an <In-Reply-To> header, so that proper message ordering can be
achieved. In theory the <In-Reply-To> is sufficient to define a thread,
but in practice it probably isn't, so having both is useful.

On the other hand, having <Thread-ID> might encourage abuse of paging
mode by providing another way to implement sessions. Just having
<Message-ID> and <In-Reply-To> would be sufficient to tie a new session
to a preceding page mode message.

	Paul Kyzivat