HiI have a scenario where Invite is forked by a proxy and it gets multiple 183 containing sdp and all are sending rtp packets as anouncements.What should the b2bua do?As we dint know which ua is going to send 200 ok
Congratulations. You've discovered promiscuous early media. That's why I think this part of the protocol spec is broken; early media (driven by PSTN-interworking) combined with forking produces an intractable problem.
Various hacks have been used to address the problem. As far as I know, none of them really work "right", but you might find one that works most of the time for your use case.
I suggest trying the sip-implementors mailing list for advice on this issue:
<sip-implementors at lists.cs.columbia.edu>Although personally, what I'd probably do is hunt down the developers of the UAs that are all sending 183 with SDP and related RTP and verbally abuse them. Of course, if the UAs are PSTN gateways, there really isn't much else they can do.
-- Dean