Date: Sat, 6 Apr 2002 18:45:26 -0800 From: "Crist J. Clark" <cjc@FreeBSD.ORG> To: Luigi Rizzo <luigi@iet.unipi.it> Cc: Andreas Klemm <andreas@klemm.gtn.com>, freebsd-net@FreeBSD.ORG Subject: Re: better DSL bandwidth usage by priorizing ACKs in outgoing packets over others Message-ID: <20020406184526.E70207@blossom.cjclark.org> In-Reply-To: <20020406065735.A29144@iguana.icir.org>; from luigi@iet.unipi.it on Sat, Apr 06, 2002 at 06:57:36AM -0800 References: <20020402163912.GD4307@titan.klemm.gtn.com> <20020406065735.A29144@iguana.icir.org>
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On Sat, Apr 06, 2002 at 06:57:36AM -0800, Luigi Rizzo wrote:
> On Tue, Apr 02, 2002 at 06:39:12PM +0200, Andreas Klemm wrote:
>
> we would need a minor tweak to the ipfw code so that it can match
> packets whose size is less than X bytes (so the mechanism is general
> enough to be used for other things). This could be done in a matter
> of 1hour or less, most of the time would be wasted in figuring out
> a way to implement it that does not break binary compatibility.
Actually, could just match ACK-only packets, no PSH?
...I'm getting some severe deja vu with this topic. But I can't recall
what the exact subject was previously.
> Once we have done this, we can define a dummynet pipe with
> a bandwidth <= the bottleneck (128kbit/s), and use"queue" rules
> to privilege the acks wrt other traffic.
>
> Something like
>
>
> ipfw pipe 10 config bw 100kbit/s
> ipfw queue 1 config weight 1 pipe 10
> ipfw queue 100 config weight 100 pipe 10
> ipfw add queue 100 tcp from any to ${outside} shorter-than 80
> ipfw add queue 1 ip from any to ${outside}
>
> This said, i have never seen terribly bad effects when cvsupping
> and doing other things. If there is something which goes to its
> knees, this is the disk.
On a previous Internet provider, I had silent PMTU issues somewhere
downstream. Ploss went through the roof when you got above 1000
bytes-per-packet upstream.
--
Crist J. Clark | cjclark@alum.mit.edu
| cjclark@jhu.edu
http://people.freebsd.org/~cjc/ | cjc@freebsd.org
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