Re: [rtcweb] Proposal for PeerConnection cloning

Martin Thomson <martin.thomson@gmail.com> Tue, 08 May 2012 15:49 UTC

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Date: Tue, 08 May 2012 08:49:03 -0700
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From: Martin Thomson <martin.thomson@gmail.com>
To: "Ejzak, Richard P (Richard)" <richard.ejzak@alcatel-lucent.com>
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Subject: Re: [rtcweb] Proposal for PeerConnection cloning
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On 7 May 2012 19:10, Ejzak, Richard P (Richard)
<richard.ejzak@alcatel-lucent.com> wrote:
> You raise a good point since some candidates may be released before cloning
> occurs.  So this is another bug in the procedure.  I would suggest that the
> configuration also be passed to the CPC and that if any of the required
> candidates are released before cloning occurs that they be reallocated.

Releasing a TURN candidate is a real possibility.  The same could
apply to local candidates (and server reflexive), though that will
depend on implementation.  Getting the same one back is unlikely for
TURN, though it might be possible for local.

In all these cases, answers that arrive late will fail.

> Alternately, we could recommend that candidates be kept allocated longer
> than usual and that if cloning is attempted after any of the candidates are
> released then the cloning procedure fails.

I'd be against making any such recommendation for browser
implementations.  The signaling application is more likely to know
best in this scenario.  In that case, it can make the call to hold
candidates open.  PR_ANSWER seems to have the right semantics.

--Martin