Simulating network impairments

I need to simulate network impairments between two computers (likely using tc-netem). Would like something which is relatively easy to set up but powerful enough for the job. Hoping to not have to spend hundreds of dollars. Any suggestions? Thanks!

And device should be able to perform the task of adding a delay with tc-netem.

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Yes, delay and jitter. Eventually packet loss as well.

Apologies. I meant to say "any device should be able".

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Are there any devices which are easier to work with than others? More reliable?

You're trying to add a delay, loss, etc. - maybe I have a different point of view.

I'd personally use an old, slow device. That's why any device would work.

It seems like you want the device to actually be the opposite.

The impairments need to be controlled by tc-netem, not by the limitations of the hardware.

It all depends on what kind of speed you want to emulate this at. A first order of approximation might be performances with sqm/cake, in other words, if you want to test at 1 GBit/s line speed, you need a fast router for that (x86_64).

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The goal is for working with real-time media. Should not require Gbps speeds. If it did, would this mean a mini pc and switch? Does OpenWRT install on a mini pc as an OS or on top of a Linux distro?

OpenWrt works fine installed on x86_64 systems (two+ network cards recommended), even booted from a USB, if you need to.

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Also Virtual Machines.

A VM would be perfect on the existing systems, if they weren’t macOS. :joy:

I'm not sure what you mean by that statement - unless you're implying that there isn't free VM Hypervisor software for Mac?

See "Mac" download here:


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Virtualbox is not very stable on M1. I can try on older x86 MacBook.

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I have OpenWRT running in a Virtualbox but a bit confused about the settings. My setup is as follows.

  • MacBook A (M1) running web / media server (en0
  • MacBook B (x86) (en0 & en10, bridge100, ) running VB-OpenWRT (Adapter 1 Host-only Network vboxnet0, Adapter 2 NAT, Adapter 3 Bridged Adapter en0 WiFi). Connects to MacBook A via. web application and establishes a media RTP connection between A and B.

I need to route the RTP traffic from B to A through OpenWRT in order to apply jitter. Could expand this in the future. OpenWRT is configured enough to support luciweb, tc-netem, etc. I’m not confident the Virtualbox network, OpenWRT network, MacBook network configuration to ensure RTP is passing through OpenWRT.

I also have the option to use ethernet between A & B via. a switch.

Thanks for any help!