Subject: Re: [Sip] can i change my own dialog info in mid-dialog?

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 30 Apr 2003 22:52:19 -0400

wenkai wrote:
> I would like make my original question more clear by dividing it into two
> parts.
> 
> The first part:
> "UA can change his local uri and remote uri by himself in mid-dialog.", i
> think it is correct in RFC3261.

To be clear; rfc3261 forbids this because of compatibility with rfc2543.

> 
> The second part:
> "UA can change his request-uri by himself in mid-dialog."  Maybe we can not
> do it.
> RFC3261 said,  in mid-dialog, "The UAC uses the remote target and route set
> to build the Request-URI".  UA can not change "remote target" and "route
> set" by himself in mid-dialog.  So, UA can not change his request-uri by
> himself in mid-dialog. The UA can change his request-uri by opposite UA's
> instruction.
> 
> I ask this question because request-uri can be used as service
> identification. If UA can change the request-uri by itself, so UA can use
> request-uri to carry different service request during mid-dialog. Maybe we
> can use parameters to achieve this target.

I have seen this proposed in the past as one of sevearl possible 
approaches for using SIP as an application control protocol. INFO is the 
other favorite. I still believe that this is generally outside the scope 
of SIP. If you want to control an application to which you have 
initiated a session, you should open a "control session" which is e2e. 
This control session, like the audio session, is signaling with the SDP, 
and based on some non-SIP protocol.

I actually really like MSRP (draft-campbell-simple-im-sessions-01) as a 
means for conveying e2e control messages. I think many folks still like 
INFO, but perhaps this is mostly because of the lack of a viable 
alternative.

Thanks,
Jonathan R.

-- 
Jonathan D. Rosenberg, Ph.D.                600 Lanidex Plaza
Chief Scientist                             Parsippany, NJ 07054-2711
dynamicsoft
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

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From: "Shane McCormack" <[email-masked]>
Date: Thu, 1 May 2003 10:36:00 +0100

Hi all,

I am currently working on my thesis which involves me creating a simplified
generic java API layer above SIP and parlay for easier service development.
This involves the creation of call objects similar to Java Call Control, and
Parlay.

When mapping an incoming INVITE (or incoming requests such as a NOTIFY for
presence for other similar objects), some mapping has to be performed. My
question is would you associate a call object with a request callid or
dialog? or both. So that when some routing operation is performed by the
client application using my API the correct incoming INVITE is referenced in
the underlying SIP stack when the call object is passed back to be routed or
proxied.

I am actually using SIP servlets for this implementation so SIP stack is not
correct term to use.

Regards

Shane McCormack

Research Assistant,
TSSG, Confederation House,
Waterford Business Park, Cork Road,
Waterford, Co. Waterford.

Phone: +353 51 302927     Fax: +353 51 302901
Mobile: +353 87 9955505
http://www.tssg.org <http://www.tssg.org/>
MSN: [email-masked] <mailto:[email-masked]>

---

From: "sal" <[email-masked]>
Date: Tue, 6 May 2003 20:41:17 +0200

I Shane,
why don't use directly Java Call Control ?

two years ago I helped a guy in his degree thesis,
we developed a SIP client over JCC...
in those days we didn't implement NOTIFY... but I think
should not be difficulto to do...

But your thesis is not on SIP over SCTP ?
maybe you don't remember we had several discussions some
months ago (more than a year ago... if I don't wrong)

Sal