TCP Vegas and tomato

23 Dec

TCP Vegas is a TCP congestion control, or network congestion avoidance, algorithm that emphasizes packet delay, rather than packet loss, as a signal to help determine the rate at which to send packets. It was developed at the University of Arizona by Lawrence Brakmo and Larry L. Peterson.

TCP Vegas detects congestion at an incipient stage based on increasing Round Trip Time (RTT) values of the packets in the connection unlike other flavors like Reno, NewReno etc. which detect congestion only after it has actually happened via packet drops. The algorithm depends heavily on accurate calculation of the Base RTT value.

Read more about it here.

Tomato Firmware recently added this algorhythm to its 1.23 version. Tomato Firmware is a free HyperWRT-based, Linux core firmware for several wireless routers, most notably the Linksys WRT54G (including the WRT54GL and WRT54GS), Buffalo AirStation and Asus Routers. Tomato is based on the GPL sourcecode released by Linksys, but includes proprietary binary modules from the chipset manufacturer Broadcom.

If your router is compatible, this is a great firmware. I’ve been using this firmware on my wrt54g V3 for about 2 years now. Currently I have the 360 on the ethernet, an xbox on the ethernet, my wife’s laptop on the wireless, my t41 on the wireless, the gateway wifi server and a ethernet desktop server all running on this little wrt54g router powered by this firmware; it has no equal. It is indeed a small but powerful firmware which will ressurect your old wrt54g (if compatible) and bring it back to life.

You can read more about tomato here.


Posted by on December 23, 2008 in Journaling


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4 responses to “TCP Vegas and tomato

  1. Chirag

    January 28, 2009 at 7:16 AM

    Thanks for this info

    I’ve been trying to tweak my router to perform well as a media server.
    I have a PS3 connected via wireless and it cometimes gets a choppy connection and I was wondering if you’ve done any sort of tweaks to work around this problem.


  2. Toby

    April 27, 2009 at 5:00 PM

    I just upgraded to Tomato 1.23 on my WRT54GS, and turned on TCP Vegas. Do you have any experience with altering the alpha/beta/gamma values? A quick look at the (mostly academic) literature on the algorithm makes me think that the defaults are tuned reasonably well for an asymmetric connection (like my cable modem). I’ve got a small Ubuntu server running 24/7, along with a couple of OS X machines, and Tomato has been really great, I have to say.

  3. Andrew

    April 28, 2009 at 2:36 AM

    Unfortunately I do not have any experience with value altering. What I did to add on my network is John (tomato firmware guy) does a fantastic job with tomato. There isn’t much to do to get it going. I applied opendns to my network because I have a daughter and I want to have peace of mind when she surfs the web. You are definitely right though in saying that the defaults are tuned well because quite frankly; this firmware is not as popular as it should be.

  4. J

    November 19, 2009 at 8:58 PM

    I also use the Tomato firmware, which obviously is far ahead of the default Linksys firmware, but frankly I haven’t tried any others.


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