A User's Guide to Network Performance


Abstract

This document describes steps that help a user seeking to get good network performance over a gigabit network achieve this goal. Althought specifically intended for networks available here at NCSA it is general enough to be of help to any user on any general TCP/IP network.

Note: This document is very out of date and is maintained for historical purposes only.

This document is a work in progress.

Probably the single most important thing to help achieve good throughput over a high-speed network is the correct setting of the TCP window size. This controls the amount of data that can be "in flight" between the two hosts. The default settings that exist on current hosts are too small to take advantage of high-speed networks and will throttle back the host unnecessarily.

For details on TCP windows including instructions on setting the TCP window size see my User's Guide to TCP windows.

There are also other architecture specific stuff that can be very important. These include buffer allocation methods and methods of delivering the data to the operating system


Von Welch <Email: vwelch@ncsa.uiuc.edu> <My Home Page>