[Kamailio-Devel] [ openser-Feature Requests-2690374 ] Do not forward response to an INVITE if no matching transac

[Alex Hermann]

Maybe I completely misunderstood the call flow, but IMHO it doesn't make 
sense at all.

On Wednesday 18 March 2009 02:11:24 SourceForge.net wrote:
> TC -> openSER : 487
> openSER -> TC : ACK
> openser -> TC2 : 487 (openSER relays the 487 once the call has been established to TC2)
Why would it send the 487 to TC2 (TC2 being an UAS)? If the response is 
forwarded at all, it should be to the UAC, not to an UAS. If the 487 is send 
to TC2, that would qualify as a bug in Kamailio.

> TC2 -> openSER : ACK
> TC2 -> openSER : BYE
> <-- Call is ended but should not -->
TC2 has no reason to end this call. Even if it received the (erroneous) 487. 
It didn't send a CANCEL itself (it didn't even send an INVITE, so the 487 can't 
possibly match any transaction), so the following paragraph doesn't apply.

> According to the RFC, once a call has been OKed and a 487 is received, TC2
> may go on with the call or send a BYE (up to it). So it behaves the right
> way (chapter 15. end of 3rd paragraph : "If the INVITE results in 2xx final
> response(s) to the INVITE, this means that a UAS accepted the invitation
> while the CANCEL was in progress.  The UAC MAY continue with the sessions
> established by any 2xx responses, or MAY terminate them with BYE.").
-- 
Alex Hermann