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Date: Mon, 5 Oct 2009 12:04:46 +0200
From: Luigi Rizzo <rizzo@iet.unipi.it>
To: Eugene Grosbein <eugen@kuzbass.ru>
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Cc: rihad <rihad@mail.ru>, freebsd-net@freebsd.org
Subject: Re: dummynet dropping too many packets
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On Mon, Oct 05, 2009 at 05:56:00PM +0800, Eugene Grosbein wrote:
> On Mon, Oct 05, 2009 at 02:28:58PM +0500, rihad wrote:
> 
> > Oh, I almost forgot... Right now I've googled up and am reading this 
> > intro: http://www-rp.lip6.fr/~sf/WebSF/PapersWeb/iscc01.ps
> > 
> > So turning to GRED would turn my FreeBSD router from dumb into a smart 
> > router that knows TCP? I thought pushing bits around at a lower level, 
> > and a sufficient queue size were enough.
> 
> No, it will still deal with IP packets but more clever.
> 
> > Still not sure why increasing queue size as high as I want doesn't 
> > completely eliminate drops.
> 
> The goal is to make sources of traffic to slow down, this is the only
> way to descrease drops - any finite queue may be overhelmed with traffic.
> Taildrop does not really help with this. GRED does much better.

i think the first problem here is figure out _why_ we have
the drops, as the original poster said that queues are configured
with a very large amount of buffer (and i think there is a
misconfiguration somewhere because the mbuf stats do not make
sense)

cheers
luigi