How to set up Tenda Nova mesh for wired backhaul - MW5, MW6, etc.

[urry]

Let me share my experience how I enabled wired backhaul.
My environment:
- ISP router with build-in LAN switch
- Distribution unit with cables to each room (wall sockets) near by the ISP router
- 4xMW6 and 1xMW3

I wanted to use the ISP's built-in switch. So I'll configure Mesh network in Bridge mode.

see commutation schema in attachment
   

1) I set up a Mesh network with all MW units in default DHCP mode with Wi-Fi wireless backhaul. In one room. To check that everything is working. Primary unit WAN port was connected to ISP router LAN switch port.
2) I put the Mesh network into bridge mode (Settings -> Internet Settings -> Bridge) and powered off all devices.
3) Connected ISP router LAN ports to rooms over the Distribution unit. Connected the MW units LAN port to the rooms wall socket. Turned on the power.
4) Checked that all nodes utilized wired backhaul:
Connection Quality: Excellent
Icon: <...>
5) Checked that WAN ports in MW units provided Internet connection as well

Finally I have 16ms ping from any room Wi-Fi according to https://www.speedtest.net.

NB:
I manage to setup wired backhaul only then Primary unit was connected via LAN port. Whereas Secondary units can connect via LAN or WAN ports. I chose LAN everywhere.
One MW unit configured as Primary and operates in one of the rooms.

Hope it helps.