[Kamailio-Users] Reg. SIP conferencing support for RFC 4579

Padmaja R urvthme at gmail.com
Wed Feb 4 13:53:49 CET 2009


Hi all,

Is it possible to use Openser as the SIP conference server? I understand
that Openser cannot do the media mixing required of a centralized media
server but if it can do the centralized signaling by acting as a focus and
let a media proxy do the media mixing, that would be good. I need ad hoc
conferencing capability. Is there any media proxy that can achieve this
together with openser?

My scenario is as follows:-

Say A and B are in a SIP call, and A and B suddenly decide to have a
conference with C. A puts B on hold and dials C' s number. After call
between A and C is up, if A presses hook flash, this sends an invite to the
conference application namely: conf at openseratlocalhost:5060 (which is the ip
and port  number at which my openser proxy would be listening). The server
should then send back 200 Ok with the contact header containing the isfocus"
parameter of the form -Contact: <sip:conference1 at mediaproxyip;isfocus> The
isfocus is an RFC 4579 based feature. The 200 Ok responses to other invites
(normal calls that do not create conference) should not include this isfocus
in the contact header of 200 Ok.

Finally, the openser proxy should be able to contact the media proxy on
receiving an invite to create the conference and send that ip and focus
information in the 200 Ok. The UA -A would then send a REFER to B and C to
refer to the media server and they disconnect with A. Then all three UAs
would individually send invite to the uri returned in the contact header and
join the conference.

Thanks,
Padmaja
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