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

Daniel-Constantin Mierla miconda at gmail.com
Wed Feb 4 15:27:53 CET 2009


Hello,

On 02/04/2009 02:53 PM, Padmaja R wrote:
> 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?
openser/kamailio cannot do that for calls. There a module for Instant 
Messaging conferencing - imc:
http://kamailio.org/docs/modules/1.5.x/imc.html

For audio conferencing, openser interacts very well with:
- Asterisk
- FreeSwitch
- SEMS

It is a pure alphabetic listing, you have to chose the one that fits the 
best for you.

>  
> 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 
> <mailto: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.
I think you can code something similar in functionality with 
configuration file of kamailio 1.5.0 + a media server. There is a new 
function that makes possible to refer/bridge users:
http://kamailio.org/docs/modules/1.5.x/dialog.html#id2507597

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
http://www.asipto.com





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