Hi, Based on what you describe, INVITE contains Offer, and 200 OK contains answer, UPDATE can be issued based on RFC 3311 Section 5 for handling of UPDATEs.
If the USER A does not support RTP/SAVP, it will reject the offer and the previous negotiated offer/answer holds good for the call. Thanks, Neel -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of chaitali CK Sent: Friday, February 18, 2005 11:06 AM To: [email protected] Subject: [Sip-implementors] doubts regd SDP Hi All, I need some clarifications regd Offer Answer Model.User A sends Invite to UserB with RTP as transport and B accepts the call with 200 and Call is established with RTP as transport User A SDP: -------------- v=0 o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com s= c=IN IP4 host.atlanta.example.com t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 and B replies with : ------------------- v=0 o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com s= c=IN IP4 host.biloxi.example.com t=0 0 m=audio 49172 RTP/AVP 0 8 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 Can B Send an Updated Offer changing the Transport as shown below: v=0 o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com s= c=IN IP4 host.biloxi.example.com t=0 0 m=audio 49172 RTP/SAVP 0 8 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
