Hi, all This thread is too big and complicated. I would summarize the discussion. For that purpose I make a simpler proposal. It is the straw-man proposal, but it will work without a problem, I think. signaling | O/A state | remote target ---------------------+-----------+-------------- init-INVITE/200/ACK | state1 | c1 re-INVITE/183-rel | state2 | c2 PRACK/200OK | [noSDP] | - UPDATE/200OK | [noSDP] | c3 UPDATE/200OK | state3 | c4 4xx/ACK | state1 | c3 <- this record is my proposal. 1. Main concept is full-rollback according to RFC3261. 2. UPDATE without SDP change remote target immediately. it doesn't rollback. 3. The rollback is NOT depend on preconditions. there is no need to check SDP attribute. 4. UAS should reject UPDATE received between 4xx and ACK. UAC should NOT send UPDATE between 4xx and ACK. 5. UAC should ignore 200 response to UPDATE(with SDP) that send before 4xx received. Now we have discussed three additional proposal. A. commit-latest-exchange(Liaison Statement ?) 4xx/ACK | state3 | c4 B. late-commit ( by Gao) if UPDATE is "a part of the original modification" 4xx/ACK | state1 | c3 else (UPDATE is "new modification") 4xx/ACK | state3 | c4 the decision depend on preconditions. C. Gonzaro's draft 4xx/ACK | state1 | c1 and he says C1. UAS should NOT send 4xx. C1. UAC should send UPDATE after sending ACK for 4xx. Is my summary up to this right ? Regards, Shinji _______________________________________________ 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
