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diff --git a/Documentation/networking/tcp-thin.txt b/Documentation/networking/tcp-thin.txt deleted file mode 100644 index 151e229980f1..000000000000 --- a/Documentation/networking/tcp-thin.txt +++ /dev/null @@ -1,47 +0,0 @@ -Thin-streams and TCP -==================== -A wide range of Internet-based services that use reliable transport -protocols display what we call thin-stream properties. This means -that the application sends data with such a low rate that the -retransmission mechanisms of the transport protocol are not fully -effective. In time-dependent scenarios (like online games, control -systems, stock trading etc.) where the user experience depends -on the data delivery latency, packet loss can be devastating for -the service quality. Extreme latencies are caused by TCP's -dependency on the arrival of new data from the application to trigger -retransmissions effectively through fast retransmit instead of -waiting for long timeouts. - -After analysing a large number of time-dependent interactive -applications, we have seen that they often produce thin streams -and also stay with this traffic pattern throughout its entire -lifespan. The combination of time-dependency and the fact that the -streams provoke high latencies when using TCP is unfortunate. - -In order to reduce application-layer latency when packets are lost, -a set of mechanisms has been made, which address these latency issues -for thin streams. In short, if the kernel detects a thin stream, -the retransmission mechanisms are modified in the following manner: - -1) If the stream is thin, fast retransmit on the first dupACK. -2) If the stream is thin, do not apply exponential backoff. - -These enhancements are applied only if the stream is detected as -thin. This is accomplished by defining a threshold for the number -of packets in flight. If there are less than 4 packets in flight, -fast retransmissions can not be triggered, and the stream is prone -to experience high retransmission latencies. - -Since these mechanisms are targeted at time-dependent applications, -they must be specifically activated by the application using the -TCP_THIN_LINEAR_TIMEOUTS and TCP_THIN_DUPACK IOCTLS or the -tcp_thin_linear_timeouts and tcp_thin_dupack sysctls. Both -modifications are turned off by default. - -References -========== -More information on the modifications, as well as a wide range of -experimental data can be found here: -"Improving latency for interactive, thin-stream applications over -reliable transport" -http://simula.no/research/nd/publications/Simula.nd.477/simula_pdf_file |