> I am facing issue with one specific service provider > where caller wants to cancel the transaction and > sends CANCEL message but UAS responds with 481 > Call Leg/Transaction Does Not Exist. I assume that > as per RFC 3261, CANCEL message should not contain > the To tag however in the below message, I can see > To tag coming in CANCEL message from service provider.
As section 9.1 indicates, the To MUST be identical (including tags). > Do you think UAS should ignore the To tag and complete > the CANCEL transaction? It is an abnormal situation; thus the UAS can basically act however it wants. If the UAS wants to be as flexible as indicated by section 9.2's use of 17.2.3, the magic cookie allows for significantly malformed messages to match. Thus some vendors might allow the malformed CANCEL to be good enough. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
