Testing the speed of your home network with Iperf

Testing your speed allows you to measure the performance of a network. To do this you need to have at least two devices one to send data and the other one to receive that data. When your device is connected to the Internet it will transmit constantly as your Mac, iPad or iPhone communicates with the Web servers that host your favourite websites.  

There are online speed tests that work well for testing your internets connection speed but very few users have an internet connection that can max out an internal home wired or wireless network. If you want to determine the full speed of your home network you’ll need a server that can transmit and receive data faster than your Internet connection. The server can be a PC or your Mac on your home network as a server and then testing the bandwidth between that server and another device also on your home network.  

A great utility to test the bandwidth between two devices is iperf, which is a common network-testing tool that can create transmission control protocol and user datagram protocol. This is a free tool that you can install on at least two Macs, designating one of them as the server and the second one the receiver. Iperf then sends data directly between the two computers, revealing the maxium speed of the wired or wireless network that is connected between them.

Running Iperf is easier run through the command line utility in the Terminal, the best way is to get it via Homebrew the open source packet management system. Other wise you can open the Terminal from spotlight and run the following command: ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

This command will install the Homebrew all you need to do to get Iperf is to then enter ‘brew install iperf3’ This will then down load the latest version and install automatically. Doing this will have Iperf installed on one Mac, use the second Mac to test the network. You need to repeat this on the second Mac.

On the first Mac which will be the server and enter the following command in the Terminal ‘iperf3 –s’ and when prompted allow Iperf to accept incoming network connections. This Mac is now looking for the receiver, for the server Mac to find that receiver you must now enter ‘iperf3 -c [IP Address of first Mac]’ into the terminal on the Mac. Iperf will then run for 10 seconds and generate output from the receiver reporting the bandwidth of your connection in megabits per second for each second of the test, with the average for the entire test at the bottom. If you have your server Mac directly to the router via an ethernet cable that will ensure you have the signal from your server to the receiver Mac at its possible best producing test results that measure the measure the performance of just that wireless hop from the router to the receiver.

When you are done testing just hit control-c in the Terminal window of the Iperf server Mac to terminate the utility. This test is just a basic home networking test but it will help measure the bandwidth or speed of your wireless router.