kls0e welcome.

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.