How to measure network speed between devices

Router
1

Hello,

I just set up a Flint 3e as my main router to upgrade to 2.5 Gbit network speed (IP e.g. 192.168.50.1). I’m using a Slate AX and Berly AX as downstream routers (IP e.g. 192.168.50.10 and 192.168.50.20).

After some research, I installed iperf3 on all devices. I can measure the network speed between the Flint 3e and the two devices as explained in various tutorials. However, it was not possible to measure the speed between the two devices - I always get a timeout.

On the Flint 3e I added this to the firewall:

root@GL-BE6500:~# iptables -I INPUT -p udp --dport 5201 -j ACCEPT  
root@GL-BE6500:~# iptables -I INPUT -p tcp --dport 5201 -j ACCEPT  
root@GL-BE6500:~# /etc/init.d/firewall restart

So what else do I have to set up to get this done?

Any help is highly appreciated.

Kind regards,

Mario

2

Hi

You need to open UDP/TCP port 5201 on the WAN side for iperf3 on both Slate AX and Beryl AX.

For detailed instructions, please refer to:

4

Thank you. It worked!

6

Just wanted to share that you may need to include the -w 4M option to your iPerf command if you aren’t seeing the expected speeds. This option helped me get 10 Gbit speeds on a few of my wired 10GbE devices as well as the expected speeds on my wireless devices.

1 Like
7

I’d also recommend iperf3 testing at multi-gig speeds using multiple streams e.g. -P 8.

Higher speeds are very latency and loss sensitive on a single stream and multi streams helps mitigate these effects. In addition on newer iperf3. versions it will also distribute load over multiple CPUs if you have multiple streams which helps prevent a single CPU core on source/target being a bottleneck.

8

Thank you for the advice.