My mistake -- CANCEL is a distinct transaction (RFC 3261 sec 9.1). The cseq value is used to match up on the INVITE that's being cancelled.
For reverse compatibility with RFC 2543, the UAS may or may not send a 487 (request terminated) response to the cancelled INVITE. I suspect this may be the source of confusion -- with only a single 200 OK response for the cancel you might guess there's only 1 transaction. -- Ryan Mitchell Telecom Logic, LLC _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
