Re: [SR-Users] rtpproxy module flags 1 and 2 question

Hi, On 10/22/2012 07:04 PM, Klaus Darilion wrote: It's actually about serial hunting e.g. on ring-timeout (maybe the term "forking" is ambiguous). Consider this scenario: A sends INVITE to proxy, which calls rtpproxy_offer to create a new session in rtpproxy. You set fr_inv_timer to 5sec, then the INVITE is sent to B, which replies with 100/180. Let's call this "branch B". After 5sec, tm triggers an internal timeout, and in a failure route you set the R-RUI to C, call append_branch and spiral the INVITE to the same proxy again, which goes through call routing again, calls rtpproxy_offer again and forwards it to C. Let's call this one "branch C". In the meanwhile, the proxy sent a CANCEL for "branch B", so you'll get a 487 back from B, where you call rtpproxy_destroy in your failure route to tear down this branch. In "normal" operation mode, this will delete the full session in rtpproxy (both B and C), because both are identified with the same call-id and from-tag. And after that, you get at some point a 200 back from C, where you call rtpproxy_answer. In this lookup, rtpproxy won't find the call anymore, because it got deleted by the rtpproxy_destroy triggered by the 487 from B. The order of the 200 for "branch C" and the 487 for "branch B" doesn't really matter. The 487 before the 200 will result in an error when rtpproxy_answer is called, because the session is gone on the rtpproxy already. The 487 after the 200 will just successfully delete the session on the rtpproxy, cutting the already established audio. And this is the reason why we pass the Via branch to the rtpproxy in the offer, answer and destory when we're spiraling a call multiple times over the proxy, in order to be able to only delete a specific branch instead of the whole session in case a branch fails. The usual configuration is to set "1" for a request when calling rtpproxy_offer and "2" in a response when calling rtpproxy_answer. For rtpproxy_destory you either set nothing when called from a request (e.g. on CANCEL from caller or BYE) to tear down all branches, or "1" when called from failure route (e.g. on negative response from callee) or "2" when called from reply route (if you don't arm a failure route for some reason). Hope this clarifies it. Andreas _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users