iperf – Measure network/link speed (bandwidth) & delay using this open source tool

iperf is a simple tool that enables network administrators to check link speed/ bandwidth between any two points of a network. Suppose, you have installed a optical fiber cable between two blocks in your LAN. Now, you want to check if the optical link supports expected speeds (like 1 GE). You can do it with iperf.

First you need to attach a computer/ laptop to one of the copper ports of the switch in which the optical fiber link terminates (in one side). Do the same thing at the other end of the optical fiber link. Download iperf and install it in both the computers and run them. iperf automatically measures the available bandwidth between the two computers (which is essentially the available bandwidth of the optical fiber cable) and gives the output on the screen.

iperf can measure both the TCP and UDP performance of the network. Along with the measured bandwidth, it also gives the reading of the latency (time taken) metric. iperf can be used to measure the connection speeds/ bandwidth between any two links of a network. For example, you can measure the available link bandwidth between a server and computer by running iperf on both. With this tool, you can check if the network links are performing to their expected levels and if not, try to identify the fault/ clog in the network.

iperf is available for both Windows and Linux. The instructions to download and operate iperf in windows is available here, and the instructions to download and operate iperf in Ubuntu is available here.


You can follow the latest Computer Networking/IT Products released for homes/small businesses & reviews by subscribing to this blog with your email address in the top right-hand sidebar box: ‘Follow by E-mail’. You can expect one mail per week (max).