They probably want to listen to the Early Media RTP : https://tools.ietf.org/html/rfc3960. Answer to your first question is 'yes". At that time you'll probably capture prompts and ring tones only - it won't be a conversation between A and B. Although you might have RTP from both A and B (I think - not 100% on this one, I'd have to read the RTP) A.C.
-----Original Message----- From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Ambrish Kumar Sent: Friday, May 29, 2015 9:11 AM To: sip-implementors@lists.cs.columbia.edu; sipc...@ietf.org Subject: [Sip-implementors] When Does RTP should start flowing after 18x or 200OK/ACK Dear Team, I am working on Lawful interception and integrating our IMS nodes (SBC) with LEA. We have got a very unusual ask form IB/RAW where they want to listen the RTP flow before call is actually answered by “B” We need your help and confirmation from any RFC which clarifies when does Media should start flowing in network : 1. Is it possible RTP media should start flowing right after offer-answer model is completed say after 18x response? 2. Or RTP Media should start flowing after 200 OK ACK response. I know most of implementation start pushing media after 200 OK ACK. But does standard mandates to start flow TWO WAY RTP right after offer-answer model is completed. Regards, Ambrish _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
