Measuring network throughput between two nodes with iPerf

In mesh networks, throughput between nodes that are supposed to talk to each other is the key performance factor. There is a handy tool called iPerf already pre-installed with our Freifunk images that can measure the actual bandwidth between two nodes. It is client-server based, so to benchmark, run
iperf -s on one of the nodes, this will start an iperf server listening to connections, and on the second node, run
iperf -c <server> -d -t 15 -i 1 -P 2, this will connect the iperf client to the server and will run a heavy raw network throughput benchmark for 15 seconds. It is always good to play around with the options a bit to get the idea and maybe fine-tune the command.
If you are about to reposition an antenna and would like to check out a continuous iperf feed while doing so, I suggest using
iperf -c <server> -d -t 360 -i 1, this will be a bit easier to lift for the tcp stack of the device.

By the way, there is iPerf3, which has been around for a couple of years now, and I hope we will include it in our future Freifunk images, so have a look at this newer version, too.