Subject: RE: [Simple] IM transport

From: "Roy, Radhika R, ALCTA" <[email-masked]>
Date: Thu, 4 Oct 2001 10:16:53 -0400

My comments as stated below [RRR]:

-----Original Message-----
From: Paul Kyzivat [mailto:[email-masked]]
Sent: Thursday, October 04, 2001 9:08 AM

....

e2e acknowledgement can provide this if the conference server manages
the acknowledgements properly. This could be a policy in the server. A
different (store and forward) policy would ack before distributing when
e2e is not important.

[RRR] If "message" is sent as "media" on e2e after establishing the session,
does the Ack not to be taken care of by the transport protocol itself (e.g.,
TCP)? (For signaling part, SIP's ACK is already taken care-of, I guess.) Am
I missing something?

---

From: Paul Kyzivat <[email-masked]>
Date: Thu, 04 Oct 2001 11:47:52 -0400

> TCP)? (For signaling part, SIP's ACK is already taken care-of, I guess.) Am

Depends on what you mean by ACK and e2e.

When sip messages are sent over tcp explicit acks are still sent back.
When MESSAGEs are sent over sip in paging mode there is an explicit 200
OK. A similar sort of explicit acknowledgement can be part of session
mode IM if we choose to make it so.

If this is done, then the definition of e2e becomes important. In a two
party session this may be fairly obvious. But if you establish a
conference using a conference mixer for the IM, there may be several
session legs. Then e2e may be defined to cover only a single leg, or it
may be defined to include all legs. It is up to the conference mixer to
decide this. If we have explicit acknowledgement of each message, then
the conference mixer can choose to do the acknowledgement either way.

	Paul