> That's a good scenario. Any others? See RFC 3262 tables 1 and 2: 100, 407, 415, 420, 500, 503, and etcetera. In case anyone cares to glance at them, there were numerous discussions early last year which led to the PRACK 488 open issues being added to the draft-ietf-sipping-sip-offeranswer-06. http://www.ietf.org/mail-archive/web/sipping/current/msg15031.html http://www.ietf.org/mail-archive/web/sipping/current/msg15146.html > The point of the PRACK is to indicate to the UAS that the 1xx it > sent was received successfully. Unless its a 401 to the PRACK, I > don't see any other reason why the UAS should continue > retransmitting the 1xx if its sent a non 2xx reponse to a PRACK. > The PRACK has served its purpose. The UAC is unaware if the PRACK has served its purpose since it doesn't know if rejected by middle box or the UAS performing the retries. Similarly the UAC doesn't know if the UAS allowed the PRACK to be fully processed if a non-481 failure response (such as 401, 500, 503, 415, 420, and 488) was returned. _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP