Subject: RE: [Simple] Message Transport Protocol (SIP vs IMTP)

From: "Sriram Parameswar" <[email-masked]>
Date: Tue, 23 Jul 2002 09:54:37 -0500

Wouldn't a 'Proxy-Require: message_session' cause the proxy to send back a
420 Bad Extension? Is this the behavior we want? After all we want the IM
Session to succeed in most cases.

Regards,

Sriram

__________________________________________
Sriram Parameswar              Phone: 972-685-8540
Interactive Multimedia Server (IMS) Fax: 972-684-3986
Nortel Networks, Richardson USA  Email: [email-masked]

-----Original Message-----
From: Paul Kyzivat [mailto:[email-masked]]
Sent: Tuesday, July 23, 2002 8:09 AM
To: James Undery
Cc: SIMPLE (E-mail)
Subject: Re: [Simple] Message Transport Protocol (SIP vs IMTP)

James Undery wrote:
> 
> Hi,
> 
> At the SIMPLE meeting I believe the consensus was to go with a SIP based
message transport, however, it was unclear if this should be SIP or IMTP.
The argument for SIP is because of rfc3261 we can now use SIP as is, IMTP
was complicated due to all the requirements of messaging that couldn't be
addressed easily; I'd definitely agree with that, however, I believe that
won't work, rfc2543 proxies may still do all the bad things IMTP was
designed to avoid. The suggestion made by Rohan (that I strongly agree with)
was to take  rfc3261 and just swap SIP/2.0 for IMTP/1.0 every time the
protocol is mentioned in the spec. This has the advantage that you know
older proxies aren't going to misbehave and the draft specifying it should
be trivial modification to Jonathan's latest draft.

To avoid misbehaving proxies, shouldn't it be sufficient to do something
like

	Proxy-Require: message_session

or something to that effect? Changing the version requires much more mucking
in the stack.

	Paul
_______________________________________________
simple mailing list
[email-masked]
http://mailman.dynamicsoft.com/mailman/listinfo/simple

---

From: Paul Kyzivat <[email-masked]>
Date: Tue, 23 Jul 2002 11:17:59 -0400

This would require use of proxies that support my hypothetical "message_session" extension. That extension would require use of the rfc 3261 features, and could otherwise
be empty. If you like, we could make it "Proxy-Require: rfc3261".

Any proxy supporting 3261 should be able to comply, and the whole point is to exclude those that don't. If you get a 420 back, then the message stream path was incorrectly
defined.

	Paul

> Sriram Parameswar wrote:
> 
> Wouldn't a 'Proxy-Require: message_session' cause the proxy to send back a 420 Bad Extension? Is this the behavior we want? After all we want the IM Session to succeed in
> most cases.
> 
> Regards,
> 
> Sriram
> 
> > At the SIMPLE meeting I believe the consensus was to go with a SIP based message transport, however, it was unclear if this should be SIP or IMTP. The argument for SIP
> is because of rfc3261 we can now use SIP as is, IMTP was complicated due to all the requirements of messaging that couldn't be addressed easily; I'd definitely agree with
> that, however, I believe that won't work, rfc2543 proxies may still do all the bad things IMTP was designed to avoid. The suggestion made by Rohan (that I strongly agree
> with) was to take  rfc3261 and just swap SIP/2.0 for IMTP/1.0 every time the protocol is mentioned in the spec. This has the advantage that you know older proxies aren't
> going to misbehave and the draft specifying it should be trivial modification to Jonathan's latest draft.
> 
> To avoid misbehaving proxies, shouldn't it be sufficient to do something like
> 
> or something to that effect? Changing the version requires much more mucking in the stack.
> 
>         Paul

---

From: "Sean Olson" <[email-masked]>
Date: Tue, 23 Jul 2002 08:32:45 -0700

I don't see the benefits of using IMTP as a protocol identifier in this
case. In fact, I think it negates
some of the benefits of using SIP as the underlying protocol altogether.
What you really want in this case
is MESSAGE-specific behavior. Or did people have the notion of sending
something other than MESSAGE
in this "IMTP" transport? I really dislike the notion of receiving a 420
in this situation. Because a session
was explicitly established with a policy to route MESSAGEs through some
set of intermediaries, it seems
a bit odd that these intermediaries wouldn't be able to handle MESSAGE
(or for that matter, loose routing
if needed)
 
/sean

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]] On Behalf Of Sriram
Parameswar
Sent: Tuesday, July 23, 2002 7:55 AM
To: 'Paul Kyzivat'; James Undery
Cc: SIMPLE (E-mail)
Subject: RE: [Simple] Message Transport Protocol (SIP vs IMTP)

Wouldn't a 'Proxy-Require: message_session' cause the proxy to send back
a 420 Bad Extension? Is this the behavior we want? After all we want the
IM Session to succeed in most cases.

Regards, 

Sriram 

-----Original Message----- 
From: Paul Kyzivat [mailto:[email-masked]] 
Sent: Tuesday, July 23, 2002 8:09 AM 
To: James Undery 
Cc: SIMPLE (E-mail) 
Subject: Re: [Simple] Message Transport Protocol (SIP vs IMTP) 

James Undery wrote: 
> 
> Hi, 
> 
> At the SIMPLE meeting I believe the consensus was to go with a SIP
based message transport, however, it was unclear if this should be SIP
or IMTP. The argument for SIP is because of rfc3261 we can now use SIP
as is, IMTP was complicated due to all the requirements of messaging
that couldn't be addressed easily; I'd definitely agree with that,
however, I believe that won't work, rfc2543 proxies may still do all the
bad things IMTP was designed to avoid. The suggestion made by Rohan
(that I strongly agree with) was to take  rfc3261 and just swap SIP/2.0
for IMTP/1.0 every time the protocol is mentioned in the spec. This has
the advantage that you know older proxies aren't going to misbehave and
the draft specifying it should be trivial modification to Jonathan's
latest draft.

or something to that effect? Changing the version requires much more
mucking in the stack. 

        Paul