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From: Jonathan Morton <chromatix99@gmail.com>
To: Juliusz Chroboczek <jch@irif.fr>
Cc: Dave Taht <dave.taht@gmail.com>,
	Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>,
	ecn-sane@lists.bufferbloat.net,
	babel-users@lists.alioth.debian.org
Subject: Re: [Make-wifi-fast] [Babel-users] reducing delays in wifi mcast queues
Date: Wed, 19 Sep 2018 09:05:45 +0300	[thread overview]
Message-ID: <7F6B1E4A-7FF1-4AB0-9770-67D18D80BB86@gmail.com> (raw)
In-Reply-To: <87zhweb9lj.wl-jch@irif.fr>

> On 19 Sep, 2018, at 3:43 am, Juliusz Chroboczek <jch@irif.fr> wrote:
> 
>>> Or perhaps, if we know which queue that is,
>>> we could modify Babel's packet scheduling to be more AQM friendly?
> 
>> How would you describe babel's packet schedulig now?
> 
> The main flaw is that it sends periodic updates as a burst of back-to-back
> full-size packets.  That could trigger Codel if you had more than 60
> routes or so.
> 
>> So dumping packets in there at a rate no more than 20ms each (short term
>> burst of 100ms) - relative to whatever bandwidth can be achieved vs the
>> other flows.
> 
> Right.  Guilty as charged.

The general principle you want is pacing, rather than bursting.  If you have a defined refresh interval, spread your routing updates evenly across that interval.  Or pick a rate to send updates at, and use ECN feedback to adjust that rate.

 - Jonathan Morton


      parent reply	other threads:[~2018-09-19  6:05 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-19  4:15 [Make-wifi-fast] " Dave Taht
2018-09-18 23:19 ` [Make-wifi-fast] [Babel-users] " Juliusz Chroboczek
2018-09-18 23:31   ` Dave Taht
2018-09-19  0:04     ` Juliusz Chroboczek
2018-09-19  0:07       ` Jonathan Morton
2018-09-19  0:32       ` Dave Taht
2018-09-19  0:43         ` Juliusz Chroboczek
2018-09-19  0:53           ` Dave Taht
2018-09-19  6:05           ` Jonathan Morton [this message]

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