2009/8/6 Vivek Batra <vivek.ba...@matrixtelesol.com>: > [Vivek] - With some ITSP's, 183 Session Progress is sent (with SDP) to play > the music (something like, please wait while your call is on wait) when > actual called party is busy. However, 180 Ringing is sent as soon as call > has been placed to called party and called party is ringing. > ITSP does not disconnect the media after sending 180 Ringing instead start > playing Ring Back Tone (RBT) to caller. Hence, in either manner while caller > disconnects the media or not on receipt of 180 Ringing (without SDP), RBT > will be played to caller either locally (if caller honors 180 Ringing) or by > remote server (if caller does not honors 180 Ringing). > I believe in having a check in application to check whether any RTP stream > is still there or not after receiving 180 Ringing (without SDP). If no RTP > is coming, then only 180 Ringing should be honored to play RBT locally else > RTP from ITSP should be played.
Other scenario: Parallel forking to phone1 and phone2 (or gateways): - phone1 replies 183 with early media. - phone2 replies 180. - UAC chooses and renders the early-media. - phone1 rejects the call. - UAC doesn't realize of it except if it checks that there is no more RTP from that early dialog. - If UAC checks it it could change to render internal ringing. Note that, AFAIK, the 199 code would be useful in this case (it is sent by the proxy when a branch has finished and would tell the UAC that the branch of the 183 has terminated). Unfortunatelly it's a new responde code (still a draft) which nobody implements. -- Iñaki Baz Castillo <i...@aliax.net> _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
