Hello! This is an often discussed topic but there is something fundamental I dont understand after looking through previous threads. The SIP spec says that in order to match a request to a response (sec 14.3): All responses to a request contain the same values in the Call-ID, CSeq, To, and From fields (with the possible addition of a tag in the To field (section 10.43)). However for the cancel: The Request-URI, topmost Via, Call-ID, To, the numeric part of CSeq and From header fields in the CANCEL request are identical to those in the original request being cancelled, including tags. This allows a CANCEL request to be matched with the request it cancels. My question is: 1. Why can the Transaction identifier for the cancel not be computed in the same way as for the response matching? 2. Why does the entire CSeq field (not just the sequence number) get used to compute the Transaction identifier in section 14.3 (i.e. does it matter if I just use the sequence number)? Thanks Regards Ranga. -- M. Ranganathan Advanced Networking Technologies Divsion National Institute of Standards and Technology (NIST) 100 Bureau Drive, Stop 8920, Gaithersburg, MD 20899. Tel: 301 975 3664 ; Fax: 301 590 0932 Advanced Networking Technologies For the People! _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
