[Infowarrior] - The problem of Bufferbloat

[Richard Forno]

The criminal mastermind: bufferbloat!

By gettys

Each of these initial experiments were been designed to clearly demonstrate a now very common problem: excessive buffering in a network path. I call this “bufferbloat“. We all suffer from it end-to-end, and not just in our applications, operating systems and home network, as you will see.

Large network buffers can be thought of as “dark buffers”, analogous to “dark matter” in the universe; they are undetectable under many/most circumstances, and you can detect them only by indirect means.  Buffers do not cause problems when they are empty.  But when they fill they introduce additional latency (and create other problems, possibly very severe) to other traffic sharing the link.

In the past, memory was expensive, and bandwidth on a link fixed; in most parts of the path your bytes take through the network, necessary buffering was easy to predict and there were strong cost incentives to minimize extra buffering. Times have changed, memory  is really cheap, but our engineering intuition is to avoid dropping data.  This intuition turns out to be wrong, and has become counter-productive.

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http://gettys.wordpress.com/2010/12/03/introducing-the-criminal-mastermind-bufferbloat/

Part 2 ....  (really good piece)

http://gettys.wordpress.com/2010/12/06/whose-house-is-of-glasse-must-not-throw-stones-at-another/