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Juan Simón
Asked: 2011-06-07 06:10:18 +0800 CST

What's the best TCP congestion avoidance algorithm to an ADSL2+ connection?

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I've read some wikis and pages about TCP congestion avoidance algorithm but I don't sure about the response to this question: What's the best TCP congestion avoidance algorithm to an ADSL2+ connection? Actually I use CUBIC, is it the best option?

networking

2 Answers

  1. Due to bufferbloat on typical consumer ADSL2+ connection the TCP congestion avoidance algorithms do not work at all. If you are suffering from that, this blog posting by Jim Gettys might be helpful. Personally, I apply bandwidth limit on the bulk uploads (scp and torrents, mainly) to not exceed half the stated capacity of my link, and that seems to be sufficient.

    If your problem is something else (for example, if you are on the DSLAM side or provide the link further downstream), please give more details.

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  2. Could your MTU be too large? See http://www.mynetwatchman.com/kb/ADSL/pppoemtu.htm

    An excessive (for your network) MTU will lead to fragmentation, and sending 2 packets along the path for every 1 MTU-sized packet you thought you sent.

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