||This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. (January 2012)|
|Developer(s)||The Iperf team|
|Stable release||2.0.5 / July 9, 2010|
|Preview release||iperf 3.0b4 (Fourth beta of reimplementation.) / August 2, 2010|
Iperf is a commonly used network testing tool that can create TCP and UDP data streams and measure the throughput of a network that is carrying them. Iperf is a tool for network performance measurement written in C++. Iperf was developed by the Distributed Applications Support Team (DAST) at the National Laboratory for Applied Network Research (NLANR).
Iperf allows the user to set various parameters that can be used for testing a network, or alternately for optimizing or tuning a network. Iperf has a client and server functionality, and can measure the throughput between the two ends, either unidirectionally or bi-directionally. It is open source software and runs on various platforms including Linux, Unix and Windows.
- UDP: When used for testing UDP capacity, Iperf allows the user to specify the datagram size and provides results for the datagram throughput and the packet loss.
- TCP: When used for testing TCP capacity, Iperf measures the throughput of the payload. One thing to note is that Iperf uses 1024*1024 for megabytes and 1000*1000 for megabits.
Typical Iperf output contains a timestamped report of the amount of data transferred and the throughput measured.
Iperf is significant as it is a cross-platform tool that can be run over any network and output standardized performance measurements. Thus it can be used for comparison of wired and wireless networking equipment and technologies in an unbiased way. Since it is also open source, the measurement methodology can be scrutinized by the user as well.
An attempt to rewrite Iperf from scratch, with the goal of a smaller, simpler code base and a library version of the functionality that can be used in other programs, called iperf3, was started in 2009. The latest beta version dates from August 2010. The website states: "iperf3 is not backwards compatible with iperf2.x".
 See also
- Ttcp, bwping, Flowgrind: tools of a similar nature.
- Measuring network throughput
- Packet generation model
 Public test servers
- Measure Network Performance with iperf (Part 1), (Part 2), article published by Enterprise Networking Planet
- Long Distance WiFi Trial, iperf used to measure 70 km Wi-Fi link
- Measuring end-to-end bandwidth with Iperf using Web100, whitepaper on modifications to Iperf to be less intrusive