Hi,
On Tue, Jul 18, 2017 at 9:42 AM, Juha Heinanen jh@tutpro.com wrote:
Is the note about "serial forking" correct or should it be about "parallel forking" instead? In case of serial forking, it would not matter if the whole call is deleted, because a new offer would be issued for the next branch. Or perhaps I just don't understand the meaning of the note?
If the proxy that does the parallel forking is the same that issues the rtpengine call, it shouldn't matter because there won't be a delete command for the cancelled branch. If you have a scenario where the proxy sends out multiple branches and for example a load balancer does the rtpengine stuff, then the load balancer should use the via branch flag or the cancelled branch will kill the call.
In serial forking, the new INVITE could go out before the CANCEL is sent out. If that happens, the Via branch is needed to not kill the whole call.
So one can think of scenarios with both serial and parallel forking, where the via-branch flag can be useful.
Regards, Sebastian