Re: [aqm] CoDel's control law that determines drop frequency

Bob Briscoe <ietf@bobbriscoe.net> Wed, 30 September 2015 13:02 UTC

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From: Bob Briscoe <ietf@bobbriscoe.net>
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Date: Wed, 30 Sep 2015 14:02:06 +0100
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Cc: Polina Goltsman <polina.goltsman@student.kit.edu>, Andrew Mcgregor <andrewmcgr@google.com>, AQM IETF list <aqm@ietf.org>
Subject: Re: [aqm] CoDel's control law that determines drop frequency
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Roland, Toke,

Yes, Toke's right - I was talking about how fast the control law moves, 
not the steady state.


Bob

On 30/09/15 13:25, Toke Høiland-Jørgensen wrote:
> "Bless, Roland (TM)" <roland.bless@kit.edu> writes:
>
>> Am 30.09.2015 um 13:52 schrieb Toke Høiland-Jørgensen:
>>> Polina Goltsman <polina.goltsman@student.kit.edu> writes:
>>>
>>>>> Early on, Rong Pan showed that it takes CoDel ages to bring high load under
>>>>> control. I think this linear increase is the reason.
>>>> Is there a link to this ?
>>> I have an analysis of transient behaviour in my recent paper (section 6.2):
>>> http://www.sciencedirect.com/science/article/pii/S1389128615002479
>>>
>>> PIE struggles with this too, BTW...
>> Thanks for the pointer, but I guess that's a different issue.
>> If I understood Bob correctly, he was referring to a steady state
>> situation with many flows (=high load?) in congestion avoidance phase.
>> But maybe Bob can clarify this...
> Well, steady state has (by definition) nothing to do with how long it
> takes to get there? Once CoDel has found the right scaling point it
> stays there, so surely the problem is with transients?
>
> -Toke
>
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-- 
________________________________________________________________
Bob Briscoe                               http://bobbriscoe.net/