Setting up 802.11s mesh on OpenWRT 21.02 routers

Update: I ran iperf3 on both 802.11s and WDS modes. 802.11s got about 150Mbps, while WDS had more than 200 Mbps. I reverted my setup to WDS.

I have two routers, Linksys EA7300v2 and Lenovo Y1, both running OpenWrt. I use WDS between them to build a wireless bridge. Recently I learned that WDS is deprecated and 802.11s is the replacement.

Here are steps to create a 802.11s mesh on OpenWrt 21.02,

1) Run command iw list | grep "Supported interface modes" -A 9 and check if the output contains "mesh point". If it does not, then the wireless driver does not support 802.11s.

2) Opkg remove the wpad-basic-wolfssl package and then install wpad-wolfssl. Because the former does not support mesh.

3) Reboot the device.

3) Append the following config to both devices' /etc/config/wireless file,

config wifi-iface '{set_a_name}'
    option device '{set_accordingly}'
    option mode 'mesh'
    option mesh_fwding '1'
    option mesh_rssi_threshold '0'
    option network 'lan'
    option mesh_id '{set_the_same_id}'
    option encryption 'sae'
    option key '{set_the_same_key}'
    option ifname 'wlan-mesh'

4) Run wifi reload.

5) Wait a few seconds and run iw dev wlan-mesh station dump. If the output is not empty, then the mesh setup is successful.

6) If the output is empty after a few minutes, run logread and see if there are any errors. I found that the EA7300 would fail to start the mesh if I set the channel to auto or a DFS channel. But the Lenovo Y1 does not have this problem. So I manually set the radios on both devices to channel 48 and it worked after wifi reload. 

References

• https://openwrt.org/docs/guide-user/network/wifi/mesh/80211s
• https://www.cwnp.com/wp-content/uploads/pdf/802.11s_mesh_networking_v1.0.pdf
• https://www.simianer.de/blog/home-wifi-setup-with-802.11s-meshing-and-802.11r-roaming