Re: [rtcweb] Why is required to have local streams before running ICE gathering? (another SDP limitation?)

Jim Barnett <> Fri, 14 June 2013 17:46 UTC

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From: Jim Barnett <>
To: Eric Rescorla <>
Thread-Topic: [rtcweb] Why is required to have local streams before running ICE gathering? (another SDP limitation?)
Date: Fri, 14 Jun 2013 17:46:26 +0000
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Subject: Re: [rtcweb] Why is required to have local streams before running ICE gathering? (another SDP limitation?)
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You can call updateICE at any point.  I also recall us agreeing to let you specify the number of candidates, but it's not in the spec. If it gets added to updateICE then you would be able to specify the number of candidates before setLocal.

On Jun 14, 2013, at 10:01 AM, "Eric Rescorla" <<>> wrote:

On Fri, Jun 14, 2013 at 4:53 AM, Iñaki Baz Castillo <<>> wrote:
2013/6/13 Eric Rescorla <<>>:
>> 1. There is agreement that there should be a mechanism to pre-specify
>> the size of a candidate pool to gather, though I just glanced in the spec
>> and I didn't see it. (May have missed it though).
> I see that there still is some (not quite up to date) text here:
> Create an ICE Agent as defined in [ICE] and let connection's
> RTCPeerConnection ICE Agent be that ICE Agent and provide it the STUN and
> TURN servers from the configuration array. The ICE Agent will proceed with
> gathering as soon as the IceTransports constraint is not set to "none". At
> this point the ICE Agent does not know how many ICE components it needs (and
> hence the number of candidates to gather), but it can make a reasonable
> assumption such as 2. As the RTCPeerConnection object gets more information,
> the ICE Agent can adjust the number of components.

Hi Eric, thanks a lot for the information you provide.

Is it feasible with the current API to ask for N ICE candidates prior
to having the local SDP set as local descriptor in the PeerConnection?

That has been discussed (and I thought agreed upon) but I don't see
it in the spec.


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