Hi
Parallel forking situation.
Btw, exactly same issue also happens with serial forking.
A => B => C
A invites with g711/g722 B generates early 'ringback' audio g711 durcing 183 B times out, serial forking to C with inital SDP from A B answers with g722
I agree with Daniel, that messages from C contain a different to tag than the ones from B, so one could argue, this is not the same session.
But I doubt the companies building SBC takes such details into account.
In fact, I traced the issue again, our commercial SBC, operating in B2BUA mode is using a different set of ToTag,FromTag on each leg and the ToTag on the A leg are the same despite the ToTag on the B leg being different after forking. So from A's point of view, an additional SDP answer is receivedin the same session, which shall be dropped.
So, still wondering, is there a way so issue a Re-Invite or Update from Kamailio?
Mit freundlichen Grüssen
-Benoît Panizzon-