Hi all, We've a situation here that happens under high load and so things are running 'out of sync' / being queued / delayed responses etc. The end result is that the call is being dropped due to 500 response, which is unwanted. Different SIP-stacks are involved here (UA1 is actually a B2BUA PBX and UA2 has call to an endpoint behind the B2BUA).
Consider SIP-dialog between UA1 & UA2. UA1 sends reINVITE to UA2, and immediately also an in-dialog UPDATE (to send updated P-Asserted-Identity value). Mind the CSeq in belows flow. UA1 UA2 ------reINVITE (CSeq=10)------> ------UPDATE (CSeq=11)------> <-----200OK (UPDATE)-------> ------reINVITE (CSeq=10)------> <-----500 Invalid CSeq-------- ------ACK (CSeq=10)----------> ------BYE (CSeq=12)----------> <-----200OK(BYE)--------------- My question: Is an in-dialog UPDATE that crosses a not-completed reINVITE (as shown in above flow) allowed? Should the B2BUA wait with the UPDATE until the ACK? If it's not allowed, do you know where this is specified in RFC's? We did some digging, but couldn't find this particular one. With regards, Eize Slange _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
