Re: [Ice] ICE PAC: When to start the timer waiting for possible peer reflexive candidates?

[Nils Ohlmeier <[e-mail]>]

>> I do think Nils' point is important though, i.e., if we have a bad server it will take a very long time to decide on 'last set of candidates', 
>> which is probably not helpful. As such I think the potential positions we can take are:
>> a) Start the timer as soon as we have an answer, regardless of any candidates.
>> b) a) + receipt of at least one remote candidate (or remote EOC). (This is Nils' suggestion).
>> c) a) + sending at least one local candidate (or local EOC).

As we are mostly concerned about the remote side: 1) not providing us with candidates, or 2) providing us with unusable candidates or 3) providing us with candidates really late I don’t see how option c) would help in any of these scenarios.
From my point of view we should choose either a) or b).

>> b) has a problem if the remote side doesn't send any candidates, which we want to explicitly allow. 
> 
> True.

Just to make sure we are all on the same page: b) is only a problem in the scenario where the remote side doesn’t send any candidates but also does not send EOC.

The EOC should allow agents which explicitly don’t want to provide candidate to get the timer started soon.
I think that leaves us with scenarios where the remote doesn’t provide host candidates, and it’s reflexive or relay candidates take for ever because of slow servers.

>> I tend to lean towards a) as the simplest option.
> 
> Keep in mind that RFC 8445 is generic, so we need to to define what we mean by "answer". I guess it means some kind of indication that makes the agent assume that the remote peer has been contacted. In ice-sip-sdp we can then map that to an SDP answer.

Good point. We basically treat the SDP answer here to be something like an beginning of ICE, because we don’t have an explicit signal for that. I think in SDP based worlds there is no need for an extra signal like that. Not sure if other use cases of ICE would benefit from an explicit begin signal.

Best
  Nils