Re: [aqm] Questioning each PIE heuristic

Jonathan Morton <chromatix99@gmail.com> Thu, 30 March 2017 09:08 UTC

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From: Jonathan Morton <chromatix99@gmail.com>
In-Reply-To: <99a7b737-fc3c-efd0-b6c8-d71a089b7de8@bobbriscoe.net>
Date: Thu, 30 Mar 2017 12:08:29 +0300
Cc: "Rong Pan (ropan)" <ropan@cisco.com>, Greg White <g.white@CableLabs.com>, "FredBaker.IETF@gmail.com" <FredBaker.IETF@gmail.com>, AQM IETF list <aqm@ietf.org>, tsvwg IETF list <tsvwg@ietf.org>
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References: <9ddba389-e368-9050-3b14-aa235c99fcb8@bobbriscoe.net> <D4FDD717.2636D%ropan@cisco.com> <77D4FC66-C99F-49D0-BB73-27A0CEF70F31@gmail.com> <99a7b737-fc3c-efd0-b6c8-d71a089b7de8@bobbriscoe.net>
To: Bob Briscoe <ietf@bobbriscoe.net>
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Subject: Re: [aqm] Questioning each PIE heuristic
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> On 30 Mar, 2017, at 10:46, Bob Briscoe <ietf@bobbriscoe.net> wrote:
> 
> For PI2 we removed all but 2 and it worked the same or better than PIE in all our tests. I have been assessing each of the other 7 one by one for reinstatement. So far I've rejected 6. I think I can reject this last one by making the sampling time of the base PI algo dependent on the max link rate. Then when the queue goes idle, the base PI algo will decay drop down to zero no slower than the queue drains, without needing this extra heuristic.

That’s fair enough.

It sounds like the fairly coarsely discrete time intervals in PIE are the main justification for this particular heuristic, so it might be sufficient to document that WRT PIE itself.  Using finer time intervals is clearly a better choice for the future.

 - Jonathan Morton