Subject: RE: [Simple] Consensus on INVITE-established IM

From: "Peterson, Jon" <[email-masked]>
Date: Wed, 3 Oct 2001 19:07:49 -0500

I don't think 'sessions' need to cross CPIM boundaries, because there is no
requirement for CPIM protocols to have a concept of a session (as we are
using the term) and we can therefore safely assume that some such protocols
will not.

What this does entail is a potential requirement for CPIM gateways to keep
state information associated with an INVITE-established session in order to
transmit the complete context of the session with each instant message that
it relays. Of course, this requirement only would apply if the information
contained in each session-based IM did not provide sufficient information,
on its own, to construct a CPIM message.

Jon Peterson
NeuStar, Inc
SIMPLE co-chair

-----Original Message-----
From: Ben Campbell [mailto:[email-masked]]
Sent: Wednesday, October 03, 2001 2:21 PM
To: Peterson, Jon
Cc: [email-masked]'
Subject: Re: [Simple] Consensus on INVITE-established IM

We seem to have concensus on that point.

I do have a requirements question, though: If we _do_ have a concept of 
INVITE-established IM sessions, does that session have to be able to 
cross a CPIM compliant gateway, perhaps to another protocol that does 
not support sessions?

My first reaction is to say yes, but I can think of a lot of strangeness 
here. For example, if I think I am end a session, but the opposite 
end-point does not know about sessions, how can it send me a message 
that is part of the session? How can it send me a message that is _not_ 
part of the session?

Peterson, Jon wrote:

> It sounds like pretty much no one out there is vehemently opposed to the
> concept of INVITE-established IM sessions (independent of what, exactly,
the
> transport for these IM will be), and that a rough consensus supports this
> protocol concept. If there is in fact any new argument to be made for
> excluding this concept, this would be a good time for someone to raise it.
> 
> Jon Peterson
> NeuStar, Inc
> SIMPLE co-chair
> _______________________________________________
> simple mailing list
> [email-masked]
> http://mailman.dynamicsoft.com/mailman/listinfo/simple
>

---

From: Ben Campbell <[email-masked]>
Date: Thu, 04 Oct 2001 10:24:05 -0500

> on its own, to construct a CPIM message.

That is one option. Another would be to say the gateway in its simplist 
form just does not accept INVITES. That is, treat IM sessions as 
optional to implement. This could save us a lot of trouble with dealing 
with the semantics of gatewaying between a session on one side and no 
session on the other. It might also remove requirements for responses to 
in-session messages over a reliable transport.

I do not think the messages inside a session should have enough info to 
construct a CPIM message. If in-session messages must cross a gateway, 
then we must establish a session with that gateway.