Subject: RE: [Simple] Implicit MESSAGE sessions revisited

From: "Patil Basavaraj (NET/Dallas)" <[email-masked]>
Date: Fri, 14 Sep 2001 13:07:43 -0500

One of the protocols that has been suggested for use instead of
MESSAGE is BEEP. Are there any serious concerns *at this time*
why BEEP would not be good eniugh for IM Sessions? 

-Basavaraj

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From: Henning Schulzrinne <[email-masked]>
Date: Fri, 14 Sep 2001 14:14:05 -0400

While BEEP is a useful protocol, I fail to see what advantages it offers
compared to "smaller" solutions that don't require as much additional
infrastructure and end system complexity.

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From: "Dean Willis" <[email-masked]>
Date: Fri, 14 Sep 2001 23:31:01 -0500

Just as MESSAGE for sessions has all the wasted overhead of headers and
routing mechanisms designed to find users and traverse firewalls (assuming
you think this is a waste), so does BEEP.

I personally have yet to see the need for message sessions as a specialized
transport.

I think "pager" messages carrying a session-ID and sequence number can
provide the same user experience.

--
dean

----- Original Message -----
From: "Patil Basavaraj (NET/Dallas)" <[email-masked]>
To: "'ext Ben Campbell'" <[email-masked]>
Cc: <[email-masked]>
Sent: Friday, September 14, 2001 1:07 PM
Subject: RE: [Simple] Implicit MESSAGE sessions revisited

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From: "Henning G. Schulzrinne" <[email-masked]>
Date: Sat, 15 Sep 2001 10:34:20 -0400

> provide the same user experience.

Just for clarification:

Are you assuming that TCP (or, presumably, SCTP) is used? Are you
assuming that the TCP connection is kept open implicitly?

(To avoid artificial disagreement: I would agree that a regular SIP
session over TCP would address most of the requirements, but just saying
"paging" isn't quite enough.)

-- 
Henning Schulzrinne   http://www.cs.columbia.edu/~hgs

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From: "Zane Thomas" <[email-masked]>
Date: Sat, 15 Sep 2001 10:21:55 -0700

Henning,

> infrastructure and end system complexity.

If, after establishing a session with SIP, your only requirement is to pass simple messages back and forth then BEEP is certainly overkill.  However, if you want to use the same (tcp for instance) connection to simultaneously pass other information - such as "out of band" file transfers, realtime presence information, or other application level sorts of information then you have the sort of problems BEEP was designed to address.

Zane

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From: "Dean Willis" <[email-masked]>
Date: Mon, 17 Sep 2001 11:30:47 -0500

No, we're clearly thinking something different here. I'm proposing providing
the concept of a "session" as a sequence of messages, with that sequence
association being indicated at the application rather than transport layer.

For example, the message body itself might contain a session identifier and
a sequence number.

This would allow the receiving client to render messages into appropriate
windows in an appropriate order, as appropriate to the implementation,
without the transport layer being aware of that behavior.

--
Dean