Wlan-bridge / Site-to-site failover when cable disconnected

Hello all,

I want to build a network setup, but I don't know yet how to realize it exactly and I need tips from you.
This will be the initial situation:

  • I have 2 edge router X, router A and router B.
  • Router A is connected to the internet
  • Router A and Router B are connected via Lan cable, as well as Wifi
  • I need to access the clients connected to router B from router A, router B needs to access the internet via router A
  • By default the traffic is routed through the lan cable (if connected)

Now the important thing: When I disconnect the Lan cable, I want the traffic to continue over Wlan with as little delay as possible.

Is my approach via a wlan bridge the right one? That would be a Wlan site-to-site connection.
Normally Router B should act more as a client and not open a subnet of its own.

Thanks for your answers.

Enable logging for both iface and net subsystems:

Then check if disconnecting the wired interface triggers some event.