Re: [rtcweb] SDP_PRANSWER followed by SDP_OFFER scenario in JSEP

Neil Stratford <neils@belltower.co.uk> Fri, 11 May 2012 15:04 UTC

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From: Neil Stratford <neils@belltower.co.uk>
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Date: Fri, 11 May 2012 16:04:31 +0100
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To: "Ejzak, Richard P (Richard)" <richard.ejzak@alcatel-lucent.com>
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Subject: Re: [rtcweb] SDP_PRANSWER followed by SDP_OFFER scenario in JSEP
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On 11 May 2012, at 15:26, Ejzak, Richard P (Richard) wrote:

> But things are different with ICE and DTLS, particularly if you want to avoid media intermediaries.  Significant clipping is a real possibility if we have to restart ICE/DTLS after the "winner" responds with 200 OK.
> 
> This is not a separate use case, but a given aspect of interworking with SIP.

The whole problem of clipping audio due to the delay between the 200OK and the media actually flowing raises a flag that we are triggering upper layers of the stack on the wrong event. 

Why is anyone sending media before the media channel is fully established? Why tell the user (or IVR etc) that the call is answered before we have a working media channel?

Neil