Hi, First, I have some doubt on the sequence of Section 3.8 of draft-ietf-sipping-basic-call-flows-01.txt:
User A issues a CANCEL (F9) without To tag, and receives 200-CAN response (F10) from Proxy 1. There is no To tag in the 200-CAN. But there is different specification in 3261, section 9.2: "... The UAS answers the CANCEL request itself with a 200 (OK) response. This response is constructed following the procedures described in Section 8.2.6 ..." And in Section 8.2.6.2 says: "... However, if the To header field in the request did not contain a tag, the URI in the To header field in the response MUST equal the URI in the To header field; additionally, the UAS MUST add a tag to the To header field in the response..." It seems 3261 mandates toTag in 200-CAN. Second, in section 9.2: "the UAS answers the CANCEL request itself with a 200 (OK) response. This response is constructed following the procedures described in Section 8.2.6 noting that the To tag of the response to the CANCEL and the To tag in the response to the original request SHOULD be the same. " So it is saying at UAS, the toTag in CANCEL should be same as that in earlier 1xx, right? But how about stateful PROXY, proxy may not remember/keep the toTag in earlier 1xx, so proxy may have to generate a new toTag for 200-CAN, which would be different from toTag in 1xx. toTag is used to identify a dialog, however. Shouldn't the toTag in one dialog cycle be SAME? Otherwise, what is the purpose of toTag in 200-CAN? Thanks for your help, Hwan _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
