Hi I would like to seek clarification on whether UAS needs to put Contact header in 180 Ringing in response to an INVITE:
In RFC3261 section 13.3.1.1: ... provisional response between 101 and 199. These provisional responses establish early dialogs and therefore follow the procedures of Section 12.1.1 in addition to those of Section 8.2.6. and section 12.1.1: The UAS MUST add a Contact header field to the response. So it seems the UAS MUST put Contact header in 180 response. But in RFC3261 table 2, Contact is listed as optional. Also in draft-ietf-sipping-call-flows-01.txt sec 3.1.1 F2 Contact header is absent. Where did I go wrong? Thanks Eric _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
