The SDP in 180 response could be used for multiple reasons e.g. for playing a ringtone from the far end switch/GW or for playing early media announcements and collecting digits etc without connecting the calls
However the SDP being carried in messages which belong to one transaction should follow the offer-answer model (see RFC 3264 for details) Sending SDP in 180 response is optional but if sent should be sent reliably (see RFC 3262 for details) Ajay -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Paulo de Arruda Borelli Sent: Tuesday, January 24, 2006 7:49 PM To: [email protected] Subject: [Sip-implementors] 180 Ringing with SDP Hi, Why would an UAC send 180 Ringing with SDP? If it's supposed to use early media, then 183 Session Progress is more appropriate, right? In my understanding, 180 with SDP is contradictory. 180 means: "play a local ringback tone". But the SDP content means: open the media path (in my scenario, the original INVITE message did include SDP too). So what is the reason for using 180 with SDP in the scenario bellow? INVITE/SDP from A to B 180/SDP from B to A 200/SDP from B to A Thank you, Paulo A. Borelli Gerente de Engenharia / Engineering Manager TMais S.A. VoIPMais: +55-11-2626-1080, r. 1136 Cell: +55-11-9282-5990 <BLOCKED::mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED] <BLOCKED::http://www.tmais.com.br> www.tmais.com.br _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
