Message: 1 Date: Thu, 26 Aug 2004 07:26:37 +0200 From: Andreas Bystr?m <[EMAIL PROTECTED]> Subject: [Sip-implementors] Playing ringback tone to the caller To: "'Sip-Implementors \(E-mail\)'" <[EMAIL PROTECTED]> Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="iso-8859-1"
Any suggestions of how to solve personal ringback tone? I want to be able to play media to the caller instead of having the caller generate its own ringback tone. If I have a media server that can play music, and is triggered by the application server, is the simplest (and most "correct") way just to start send to the ip stated in the INVITE? What happens if there are forking, I guess the risk is that it can be several streams sent to the caller? If the offered codecs from the caller cant match the codecs in the invite, is there a way to negotiate this without sending 200 OK?
I have tried to find some call flows describing this case, but hae failed. Does anyone know of where I can find call flows describing personal ringback tone?
Regards, Andreas
Andreas,
Your UAC should handle forked INVITEs and early media regardless of whether your UAS chooses to send early media containing ringback.
Which early media stream the caller hears (if any) is based on local policy, not standards. The UAC must be prepared to RECEIVE multiple early media streams, but not necessarily play them out.
I prefer to respect the first 18X (media or not), until the first final response, although I've seen requirements that call for playing the media from the most recent 18X as well.
Usually, 180 is used to trigger local ringback generation, and 183 is used when ringback is coming over the RTP stream. But this is just what I've observed and probably not a standard.
-troy
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