Subject: RE: [Simple] Sessions of MESSAGEs

From: Jonathan Rosenberg <[email-masked]>
Date: Tue, 21 Aug 2001 09:31:12 -0400

> -----Original Message-----
> From: Dean Willis [mailto:[email-masked]]
> Sent: Tuesday, August 21, 2001 12:22 AM
> To: [email-masked]
> Subject: Re: [Simple] Sessions of MESSAGEs
> 
> As for #3, I like it -- I think it has a lot of advantages, 
> and Robert has
> definitely hit on some of them. But not all .For example, at 
> some point,
> we'll have the same kind of "privacy" concerns with message 
> routing as we
> now have with call routing. We'll want suppression of source location
> information, network-authenticated remote-party-ID, the 
> Privacy: header and
> its accompanying semantics, etc. Guess what? We've already 
> figured those out
> for SIP "system" messaging, for the most part. 

These are all arguments for the session model. You still get all of that -
privacy protection, network authenticated R-PID, privacy, etc.,
independently of how the media is transported. The only real argument for
SIP transport of the IMs themselves is that you can get nat traversal using
proxies. This does not seem to be a strong enough reason, given the other
technical problems, and the fact that this traversal is possible with other
means, such as the TCP version of the entfw traversal draft.

> On the other hand, do we really need a "message session", or 
> are serialized
> "pager messages" with retransmission and in-order assembly by the
> application good enough?

There are numerous advantages to the session model, which include ease of
multiparty conferencing, reduction of the load on the proxy network, ease of
transfer, hold, and other sip-supported services, and so on. 

-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

---

From: "Dean Willis" <[email-masked]>
Date: Tue, 28 Aug 2001 13:34:01 -0500

Excuse me, but it the messages in a session are transported end-to-end,
you've blown the whole privacy thing. They MUST be proxy-moderated to
provide privacy -- and if the messages have to traverse message proxies, why
not use the same proxies that are used for signaling, inasmuch as the
signaling proxies already support privacy? Messages must also be
proxy-routed to provide network-authenticated remote-party-ID.

In this case, "the media is the mesage" is perfectly true.

--
Dean

> transfer, hold, and other sip-supported services, and so on.

Conferencing is the same order of problem either way. Reduction of load on
the proxy network does not apply if, according to my above argument, the
messages are proxy-routed anyhow. "Hold" is a silly concept -- just stop
typing. Transfer can be accomplished by sending a URL in part of the message
stream.

--
Dean