How do I test a network switch?

hayheather · January 8, 2018

More excitement in upgrading my home network. I recently upgraded my old netgear switch to a new TP-Link gigabit switch (TP-LINK TL-SG108). When I added it to my network I started having some ridiculously long timeout issues with wired clients, but not wireless clients. I'm fairly certain it's an issue with the switch (it's the only thing I changed and it's unmanaged). My question is: Is there a way to definitively test that a network switch has decided it doesn't want to be a switch anymore? I understand that if you plug it in and it doesn't work, you know it's broken. I was more wondering if there are any tools or series of somethings so that I can prove to myself and a RMA department that my switch is broken?

tl;dr: How do I test a network switch?

Thunderzzu · January 8, 2018

Funnily enough, i just bought one last week for a company i was working for. The thing i tend to do with dumb switches (which hasn't been proven to work but has also not been proven not to be working) is plug in the "input" cable in port 1, turn on the power, wait for like a minute, and then start plugging devices in from the other side of the switch (from 9 to 1). I've never had a problem by doing this but at the same time, i also haven't experienced issues as you have mentioned. There aren't any tools for testing dumb switches - what you can do, is repeatedly ping devices on the other side of the switch to see what the timings are.

IrwinAllen13 · January 9, 2018

There are tools to a network that can help with a unmanaged switch. What you will need to do is download a program called iPerf3.

To perform the test you will need to computers with a gigabit port (mainly to test the full speed). This test will simply test for throughput, and latency of the switch. The idea here is to have just two PC's plugged into the switch, both with iPerf3. Once the PC's are setup then you will need to run iPerf3 as a "Server" on one PC and then run the "Client" on the other PC. This will simply test TCP traffic by default, but then you can test UDP by using a different command.

Here is the link to iPerf3: https://iperf.fr/

Note: That iPerf won't tell you what is wrong, but only that there is a problem. Also, you will need to bench mark your PC's running back-to-back (either with a Crossover Cable or a Straight Through Cable).