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Re: [rtcweb] New SDP O/A required if selected ICE candidate does not match c= line?

Christer Holmberg <christer.holmberg@ericsson.com> Thu, 24 October 2013 07:46 UTC

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From: Christer Holmberg <christer.holmberg@ericsson.com>
To: Iñaki Baz Castillo <ibc@aliax.net>, "rtcweb@ietf.org" <rtcweb@ietf.org>
Thread-Topic: [rtcweb] New SDP O/A required if selected ICE candidate does not match c= line?
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Date: Thu, 24 Oct 2013 07:46:07 +0000
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Subject: Re: [rtcweb] New SDP O/A required if selected ICE candidate does not match c= line?
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Hi,

If you use BUNDLE, you'll need a second SDP O/A to "fix the port" (assuming the first SDP O/A contains unique ports for each m- line). It doesn't have to be the same SDP O/A which "fixes the c=line" for ICE, but it can be.

Regards,

Christer

-----Original Message-----
From: rtcweb-bounces@ietf.org [mailto:rtcweb-bounces@ietf.org] On Behalf Of Iñaki Baz Castillo
Sent: 24. lokakuuta 2013 3:45
To: rtcweb@ietf.org
Subject: [rtcweb] New SDP O/A required if selected ICE candidate does not match c= line?

Hi, RFC 5245 (ICE) says:

-----------------------------
  4.1.4.  Choosing Default Candidates

   A candidate is said to be default if it would be the target of media
   from a non-ICE peer; that target is called the DEFAULT DESTINATION.
   If the default candidates are not selected by the ICE algorithm when
   communicating with an ICE-aware peer, an updated offer/answer will be
   required after ICE processing completes in order to "fix up" the SDP
   so that the default destination for media matches the candidates
   selected by ICE.  If ICE happens to select the default candidates, no
   updated offer/answer is required.
------------------------------

Having to perform a second SDP O/A just to "fix the c= line" seems terriblly annoying and unuseful IMHO. Said that, this is obviously "violated" by WebRTC browsers, right?

Thanks a lot.



--
Iñaki Baz Castillo
<ibc@aliax.net>
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