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I'm trying to enable TCP Vegas congestion control on Centos 5.4 box. According to Vegas home page it is as simple as echo 1 > /proc/sys/net/ipv4/tcp_vegas_cong_avoid but this file does not exist. I found kernel module /lib/modules/2.6.18-164.el5/kernel/net/ipv4/tcp_vegas.ko but insmodding it does not cause the file to appear. Any suggestions?


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up vote 1 down vote accepted

The sysfs interface may have changed since the webpage you've read were written.

Looking at my CentOS 5 box, it seems you might have to do something along the lines of

echo vegas > /proc/sys/net/ipv4/tcp_congestion_control

On kernels newer than 2.6.20 the possible values are listed in tcp_available_congestion_control, but I'm uncertain of where/if it's listed for prior kernels.

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Thanks. I also found that loading the mentioned module changes the value of tcp_congestion_control to vegas, but, of course writing to the file is the proper and easier way to do it. – jackhab Mar 2 '10 at 13:21
It's one way of doing it. There's also 'sysctl -w net.ipv4.tcp_congestion_control=vegas' (which also can be done at boot-time via /etc/sysctl.conf providing the kernel-module have been loaded) – Kjetil Joergensen Mar 2 '10 at 15:31

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