Re: [Sipping] Thoughts on the conf-info package

[Rohan Mahy <rohan@cisco.com>]

Hi,

I don't want to rely on a proxy being able to find now-a-mixer@


On Tuesday, June 25, 2002, at 03:16 PM, Alan Johnston wrote:

> Jonathan,
>
> See my comments below.
>> Let me give an example. A calls B. A's INVITE looks like, in part:
>>
>> INVITE B
>> Contact: sip:A@1.2.3.4
>>
>> B accepts and sends a 200 OK. A then calls C, and then decides to
>> conference them both together. It acts as a local mixer. It
>> would send a
>> re-INVITE to B:
>>
>> INVITE B
>> Contact: sip:now-a-mixer@1.2.3.4
>> Allow-Events: conf
>> Resource-Characteristic: mix
>>
>> The URI for the conference is sip:now-a-mixer@1.2.3.4.
>
> This is essentially A acting as a 3pcc to establish a new session (the
> conference) with B.
>
> This is very close to what I was thinking, but I recall Henning talking
> at the interim meeting about a conference URI (which is an AOR instead
> of a Contact).
why does it have to be an AOR?  it could be either.  it should be up to 
A.

> It is also very similar to your original join URI passed
> around in the "To-Join" header.  If A's URI is sip:A@here.com then the
> conference URI would be sip:now-a-mixer@here.com, which probably
> resolves to the Contact sip:now-a-mixer@1.2.3.4 which may be A's UA if
> it is mixer, or may be A's conference bridge.

> Within a dialog, A could make the transition using a re-INVITE and the
> change of Contact (and probably SDP) as you show.  However, to add in
> the third (or fourth...) party, a conference URI which is an AOR would
> be needed.
why?  I should be able to handle an arbitrary number of dialogs for a 
Contact URI.  Also I should be able to use one or more conference URIs 
to identify a conference, as long as all of them only refer to that 
single conference.

> A could send a REFER to D with the conference URI as the
> Refer-To, or it could send the REFER to the conference bridge with the
> Refer-To as D, or it could act as a 3pcc and send an INVITE to D using
> the bridge SDP and Contact.

> Of course, the conference URI must be registered, but I think this is a
> small price to pay for the generality you get.
it may not be possible to register these new AORs.  You should be able 
to do this:

INVITE B
Contact:A@1.2.3.4

reINVITE B
Contact: A;conf=1@1.2.3.4

Also, there is still value in an explicit Join header.  Say I (A) am 
talking to you (B), and i yell to my receptionist to join in the call to 
jot down a date or a phone number.   The receptionist (C) could send an 
INVITE with a Join header to join the call (which isn't a conference 
yet).

So C sends:
    INVITE A
    Join: 42839829;to-tag=09893;from-tag=29445

A responds
    200
    Contact: A;conf=1

A also immediately sends a reINVITE

   INVITE B
   Contact: A;conf=1

hope this makes sense.
thanks,
-rohan



_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sip@ietf.org for new developments of core SIP