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

Nils Ohlmeier <nohlmeier@mozilla.com> Fri, 26 April 2019 21:18 UTC

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From: Nils Ohlmeier <nohlmeier@mozilla.com>
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Date: Fri, 26 Apr 2019 14:18:28 -0700
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Cc: Christer Holmberg <christer.holmberg@ericsson.com>, "ice@ietf.org" <ice@ietf.org>
To: Roman Shpount <roman@telurix.com>
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Subject: Re: [Ice] ICE PAC: When to start the timer waiting for possible peer reflexive candidates?
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> On Apr 26, 2019, at 13:46, Roman Shpount <roman@telurix.com> wrote:
> 
> Hi Christer,
> 
> On Fri, Apr 26, 2019 at 4:28 PM Christer Holmberg <christer.holmberg@ericsson.com <mailto:christer.holmberg@ericsson.com>> wrote:
> In a non-trickle case, I think it would be very strange if the agent didn’t get any candidates front the peer agent.
> 
> 
> I have just sent a message to the mmusic list regarding ice-sip-sdp and offers with no candidates. There is nothing that technically prohibits it in RFC 5245, so I thought it makes sense to add a note which explicitly allows it in ice-sip-sdp.
> 
> There is a valid use case for this, when client is behind NAT and it would only communicate with a server on public address. In such cases, client does not need to collect any candidates and simply send the offer. Once it gets the answer from the server with the public address, client can send a STUN bind request to server address using a local socket not bound to any address, which will use default route. There are multiple benefits for implementing it this way, one of which would be client privacy.

Intersting idea. I think this actually works more generally in case the other side indicates to be ice-lite, or if it’s know to be ice-lite.
In other words: this should also work the client being the SDP answerer.
But in any of these cases you would need to know that the other side supports ICE PAC, or?

Best
  Nils Ohlmeier