[SR-Users] parallel media forking during ringing phase

[Tomas Zanet]

Hi all, I'm writing to the community because I need a hint from Kamailio and voip gurus: the goal is adding parallel forking call with early-media to our PABX where there's a Kamailio instance running.
I mean media streams should be sent to all call destinations before answering the call order, for instance, to see the incoming video.

As far as I know, from signaling side should not be a problem because, using Kamailio, there’s append_branch function which forks many branches to all users.

The problem is related to media streams because there’s no way to fork media to all users after 180 + SDP or 183, right?
Obviously all users must negotiate the same media because media transcoding is basically impossible, especially for video streams.

I think there are two ways to do that:
1) using Kamailio and Asterisk. Asterisk has Queue function with ringall strategy, but I’m not sure if Asterisk supports multi domain scenarios.
Have ever used Asterisk with Kamailio in multi domain scenarios?

2) enhancing rttpproxy-ng. I don't really know the effort to achieve that.

In your opinion, what’s the easiest way to achieve that?

Thanks,
Best Regards.



Tomas Zanet
Software Design Department
tzanet at came.com
CAME S.p.A.