Re: [MMUSIC] Merging ICE aggressive and regular nomination (was Re: [tram] Comment on draft-williams-peer-redirect-01: might it not converge?)

Jonathan Lennox <> Wed, 30 July 2014 22:51 UTC

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From: Jonathan Lennox <>
To: Martin Thomson <>
Thread-Topic: [MMUSIC] Merging ICE aggressive and regular nomination (was Re: [tram] Comment on draft-williams-peer-redirect-01: might it not converge?)
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Date: Wed, 30 Jul 2014 22:51:08 +0000
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Subject: Re: [MMUSIC] Merging ICE aggressive and regular nomination (was Re: [tram] Comment on draft-williams-peer-redirect-01: might it not converge?)
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On Jul 30, 2014, at 6:28 PM, Martin Thomson <> wrote:

> On 30 July 2014 15:20, Jonathan Lennox <> wrote:
>> I don’t think you want a rule of “most recently received USE-CANDIDATE” to
>> determine the selected pair.  Checks will race each other, especially when
>> the paths’ RTTs are very different.
>> In my model, there is only ever one USE-CANDIDATE sent per component — i.e.,
>> it works like pure regular nomination, except for the “early media”.
> If the controlled peer really does use this as a signal that it's safe
> to close out other candidates, then you really do have to have just
> the one instance.  Is attaching that semantic safe?  I assume that we
> would have to signal in both directions that this new meaning is
> acceptable first.  (a=ice-options again)

5245 8.3.1:
   Once ICE processing
   has reached the Completed state for all peers for media streams using
   those candidates, the agent SHOULD wait an additional three seconds,
   and then it MAY cease responding to checks or generating triggered
   checks on that candidate.  It MAY free the candidate at that time.
You enter the “Completed” state once all components of all streams have sent or received (as appropriate) USE-CANDIDATE.

The “all peers” clause is needed for SIP, to handle forking cases.  For non-forking uses of ICE, “all peers” is equivalent to “the peer”.