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From: Dave Taht <dave.taht@gmail.com>
To: Alessandro Bolletta <alessandro@mediaspot.net>
Cc: "Codel@lists.bufferbloat.net" <Codel@lists.bufferbloat.net>
Subject: Re: [Codel] R: Making tests on Tp-link router powered by Openwrt svn
Date: Fri, 21 Dec 2012 05:54:07 -0500	[thread overview]
Message-ID: <CAA93jw4oB0rrpqK7ponSiCp9NSuJd24oGTYVH4gPqgOuGvHbTA@mail.gmail.com> (raw)
In-Reply-To: <CAA93jw7eWzMb_zk9euVZzYWfn2X9JG85cNkk7bz4hy7rxBXdWQ@mail.gmail.com>

To be more clear here;

You outlined your setup as:

laptop <- TPLINK <- gigE switch <- server

And your path for attempting fq_codel is on a samba download from the
server. So it hits the gigE switch, gets buffered up and dropped
there, and then has a clear path the rest of the way to your laptop.

The reverse path is clean (you are just sending 66 byte acks, so there
is no bottleneck in that direction).

So to get some benefit from fq_codel in this situation you would have
to put a rate limited *ingress qdisc on the TPLINK (using qos-scripts
or simple_qos), and even then a lot of drops would happen in the gigE
switch on bursty traffic.

If you were instead doing an upload to the server from the laptop,
merely having fq_codel on there would keep your latency under upload
sane.

Hope this helps.

-- 
Dave Täht

Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html

  reply	other threads:[~2012-12-21 10:54 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-20 17:57 [Codel] " Alessandro Bolletta
2012-12-20 18:07 ` Jonathan Morton
2012-12-21 10:19   ` [Codel] R: " Alessandro Bolletta
2012-12-21 10:32     ` Dave Taht
2012-12-21 10:54       ` Dave Taht [this message]
2012-12-21 17:06       ` Kathleen Nichols
2012-12-21 17:13         ` Jim Gettys
2012-12-21 19:13           ` Kathleen Nichols
2012-12-21 19:34             ` Jim Gettys
2012-12-21 17:43         ` Dave Taht
2012-12-21 17:51           ` Kathleen Nichols
     [not found] <2lps03vacpqmtehlf4gnq634.1356112034562@email.android.com>
2012-12-21 18:30 ` Jim Gettys
2012-12-21 18:57   ` Dave Taht
2012-12-21 19:29     ` Jim Gettys

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