[Codel] R: Making tests on Tp-link router powered by Openwrt svn

Dave Taht dave.taht at gmail.com
Fri Dec 21 05:54:07 EST 2012

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

Hope this helps.

Dave Täht

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

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