RFC is very clear about this scenario, please read completely The UAS MAY send a final response to the initial request before having received PRACKs for all unacknowledged reliable provisional responses, unless the final response is 2xx and any of the unacknowledged reliable provisional responses contained a session description. In that case, it MUST NOT send a final response until those provisional responses are acknowledged. If the UAS does send a final response when reliable responses are still unacknowledged, it SHOULD NOT continue to retransmit the unacknowledged reliable provisional responses, but it MUST be prepared to process PRACK requests for those outstanding responses.
That simply means if PRACK has not been received, then UAS can send final response only when 1. Final response is not 2xx AND 2. Any Un-Acknowledged Reliable Provisional Response didn't contain a SDP. If above 2 conditions are met, in that case UAS a. Stop re-transmitting 1xx ( which are not acknowledged) b. Must wait for PRACK as associated with Non-INVITE-Transaction-Timer. -------------------------------------------------------------- Thanks Abhishek _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
