Subject: Re: [Ice] Peter's review of ICEbis - removal of lower-priority candidate pairs (5.1.2.5)

From: Christer Holmberg <[email-masked]>
Date: Mon, 29 May 2017 06:13:19 +0000

Hi,

> - If we remove lower-priority candidate pairs across check lists, what
>happens if a certain check list is starved because all of its candidate
>pairs are lower priority?
> One option might be to say the limit is per check list.  Another is to
>recognise that it might happen but live with it.

My understanding was always that the limit is per check list, but I agree
it may not be very clear.

Perhaps we could modify the text as below:

   In order to limit the attacks described in Section 15.4.1, an agent
   MUST limit the total number of connectivity checks the agent performs
   across all CHECK LISTs to a specific value, and this value MUST be
   configurable. A default of 100 is RECOMMENDED.  This limit is
   enforced by, within each CHECK LIST, discarding the lower-priority
candidate 
   pairs of that CHECK LIST, until there are less than a total of 100
candidate 
   pairs in the CHECK LIST SET. The discarding of candidate pairs SHOULD be
   distributed equally throughout the CHECK LISTs in the CHECK LIST SET.

Regards,

Christer

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From: Peter Thatcher <[email-masked]>
Date: Thu, 01 Jun 2017 01:13:22 +0000

So basically add that it should be evenly distributed to avoid starving one
check list?

That sounds good to me.  Just make sure you don't have 101 check lists :).

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From: Christer Holmberg <[email-masked]>
Date: Thu, 1 Jun 2017 06:41:40 +0000

Hi,

>So basically add that it should be evenly distributed to avoid starving one check list?

Correct.

>That sounds good to me.  Just make sure you don't have 101 check lists :).

In normal cases I guess we’d be nowhere near 100, but note that if we have separate check lists for RTP and RTCP (see your other e-mail) we are talking about 50 RTP/RTCP (non-mused) flows – which still is a very big number.

Regards,

Christer

On Sun, May 28, 2017 at 11:13 PM Christer Holmberg <[email-masked]<mailto:[email-masked]>> wrote:
Hi,

Regards,

Christer