IEEE 802.11s what a Mesh!

OpenWrt 24.10 was released on the 6th of February 2025, Great! I thought switching my Cudy WR3000S and 2x Cudy WR3000 routers to OpenWrt would be a great weekend project.

For the most part it was.

Flashing the firmware was easy enough, first you have to flash Cudy’s intermediate firmware and then flash the official sysupgrade release from OpenWrt, all very nicely documented here and here

I decided that I would switch the WR3000s first as this would be the main router in a mesh network, no issue there, flashed without incident took about 6 or 7 minutes once every thing was prepared.

I configured CAKE SQM QoS; again without incident, and even switching to unbound as a more secure “on device” DNS server was mostly trouble free (although I did realise that planning to run “Adguard at home” on device was a tad too ambitious – although I had a solution in mind, now for another day)

Then when I finished I moved onto setting up the Mesh network. This will have been about 2000 GMT

Flashing the WR3000 went well, and soon I had 2 OpenWrt devices ready to go.

I had already set up a 5Ghz Wireless network and after watching a few videos on you tube and reading the OpenWrt wiki I elected to use the 5Ghz Radio for my Mesh Backhaul.

I clicked add new, changed the type to 802.11s, my country to GB added in a unique identifier, set a strong mesh password, and as my routers were capable I set it to use 160mhz on channel 36.

I did likewise on the mesh mode additionally ensuring that devices DHCP servers were deactivated on the interface being used (booth ipv4 and ipv6).

The two devices appeared top mesh(more on that in a bit) and I moved onto the 3rd device, Flashed without an issue and followed the instructions for mesh set up.

Then it all went to Shit

I noticed that the second device/node was only capable of handling ~20Mbps and the third only 5Mbps! this was very wrong, I checked and double checked all the settings, and at about 0600 hours decided to call it, for the night – my network was no more, I wanted to fix it but was simply too tired, so I went to bed.

3hours and 56minutes later I woke, feeling crappy, tired and dejected.

I pushed onward, re watched a video or two, read some more, and noted that at the bottom of one of the pages I was reading in a section called ‘more resources’ it had a link that read “A very outdated and somewhat misleading video that nevertheless serves as a basic introduction to 802.11s mesh networking: on Youtube“

This was one of the videos I had watched to prime myself! I then also noticed at the top of a wiki page I had not previously seen “WARNING! This document contains many errors and misconceptions.“

Niice!

As I am not one to give up easily (some would call me stupid, you know who you are!) I re examined everything reread everything and discovered 3 main points

Mesh back-hauls in OpenWrt have to be on the same channel, and don’t like 160mhz , they want 80Mhz

The default OpenWrt releases come with a basic version of the wpad library’s needed, after installing remove the wpad-basic package that is installed and replace it with the same package that starts wpad-mesh

Don’t incrementally commit changes for the mesh, save the changes as you go, on each device and then commit them all when you are ready in turn.

This seems to have worked for me, and am getting about 90% of my line speed (CAKE SQM) even on the node furthest away with minimal buffer-bloat

While this has only been active for the past 3 hours or so (currently 1924 hours) I am cautiously optimistic.

I have decided I want to understand OpenWrt a bit better, my next project will be setting up an OpenWrt “Adguard at home” instance on an old CubieTruck I have, and possibly throw in some other functionality too, I will post about that when I completed it, until then I’m off to bed!.