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Re: [rtcweb] Symmetric RTP and uni-directional media streams

Harald Alvestrand <harald@alvestrand.no> Thu, 01 September 2011 11:29 UTC

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Date: Thu, 01 Sep 2011 13:30:55 +0200
From: Harald Alvestrand <harald@alvestrand.no>
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To: Christer Holmberg <christer.holmberg@ericsson.com>
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Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] Symmetric RTP and uni-directional media streams
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On 09/01/11 13:23, Christer Holmberg wrote:
> Hi,
> There has been much talk about the usage of symmetric RTP. Also, 
> draft-perkins-rtcweb-rtp-usage suggests that symmetric RTP is required.
> However, the PeerConnection API currently only supports the 
> establishment of uni-directional streams, so for a single two way 
> communication one needs to create two separate uni-directional streams.
> So, I assume that one requirement from RTCWEB to W3C will be to add 
> support of the establishment of bi-directional streams to the 
> PeerConnection API.
To be precise:

I think (and we're implementing) that between two PeerConnections, there 
will be a small number of *RTP sessions*  (ideally one). These will be 
bidirectional.

These will be used for transporting any number of *MediaStreams* (a 
WEBRTC API concept), each of which corresponds to a CNAME (RTP protocol 
concept). These are unidirectional.

So the right answer is "yes" and "no", as far as I can see.
> Regards,
> Christer
>
>
> _______________________________________________
> rtcweb mailing list
> rtcweb@ietf.org
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