Wednesday, January 25, 2012

How Google Wants to Make TCP Faster

Google has some ideas how to make the Transmission Control Protocol (TCP) a little bit faster. Earlier this week, Google’s Yuchung Cheng wrote about some of Google’s research and ways that the “make the web faster” team suggests improving TCP. This includes things like increasing the initial congestion window, reducing the initial timeout for TCP, and using a new algorithm for loss recovery. According to Gooogle, this would decrease network congestion and boost page load speed significantly.
  • Increasing TCP’s initial congestion window would reduce network latency by about 10%, according to Google research. Currently the window is four segments, which is good for transmitting about 4KB of data. Google wants to increase this to 10 segments, or about 15KB.
  • Google says that using TCP Fast Open would decrease HTTP transaction network latency by 15% and whole-page load time by 10% (on average) and up to 40% in some cases. This is because fast open would enable data exchange during the TCP initial handshake, which would decrease latency by a full round-trip.
  • Google also wants to shorten the initial timeout by two seconds. This would give connections one second to time out, which Google argues is plenty on modern networks.
  • The Proportional Rate Reduction for TCP that Google developed is already implemented in Linux, and is proposed by Google as a standard.

Cheng says the company is also working on better recovery on noisy mobile networks and more. The work being done by Google is all open source, says Cheng, and submitted as standards proposals to the IETF.

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