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

From: "Sriram Parameswar" <[email-masked]>
Date: Wed, 24 Jul 2002 10:30:37 -0500

I am a little confused by this talk of proxies messing around with the SDP
*without* using session-policy. I distinctly remember that such proxies were
labelled BBUA's and BBUA's were  considered evil.

Next question - this business of introducing intermediaries only for IM; we
should re-visit it. As has been noted in preceding conversations - in the
standards we do no such thing for other media like voice and video.

Thanks,

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: Jonathan Rosenberg [mailto:[email-masked]]
Sent: Wednesday, July 24, 2002 7:56 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked];
[email-masked]; [email-masked]
Subject: Re: [Simple] Message Transport Protocol (SIP vs IMTP)

[email-masked] wrote:
> I agree in removing the proxy modifying the SDP part in the spec. But we
> need session-policy and message-session to complete in parallel.

Not really. Message sessions will work without session policy, and you 
will be able to use intermediaries too. You will just need to muck with 
SDP, as we have always been doing (and will continue to be done, I 
suspect).

> 
> There is a requirement for messages to do through intermediaries and
> session-policy should fix that.

Session-policy is one way to fix that.

-Jonathan R.

-- 
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

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---

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 25 Jul 2002 02:07:56 -0400

Sriram Parameswar wrote:
> I am a little confused by this talk of proxies messing around with the
> SDP *without* using session-policy. I distinctly remember that such
> proxies were labelled BBUA's and BBUA's were  considered evil.

Sure, that hasn't changed. My point is only that we ought not special 
case messaging here. If people in deployments need intermediaries, they 
will do what they have already been doing for voice, mucking with sdp, 
despite the lack of blessing from ietf.

> 
> Next question - this business of introducing intermediaries only for IM;
> we should re-visit it. As has been noted in preceding conversations - in
> the standards we do no such thing for other media like voice and video.

I was proposing not to special case messaging.

-Jonathan R.

---

From: Rohan Mahy <[email-masked]>
Date: Mon, 29 Jul 2002 10:03:49 -0700

> despite the lack of blessing from ietf.

Well, alternatively we could take a similar approach to the identity 
draft.  intermediaries can reject offers and answers for a variety of 
reasons (can't see the SDP to open pinholes (firewall controller), or 
the SDP violates some local administrative policy (not authorized to use 
as much bandwidth), or the controller suggests a new SDP in the 
rejection (ex: a NAT-style middlebox controller).  all of this is 
totally in the purview of a proxy.

thx,
-r

> I was proposing not to special case messaging.
agreed!

> -Jonathan R.
>
>
>
> -- Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.