I've got the following setup:
2 routers, each in a building.
the 2 routers are connceted to each other via a laser and wifi for backup.
with ospf I've got the configuration that wifi takes over when the laser goes down, or when the weather goes bad (rain, fog).
But as you know, weather is unpredictable. So if the laser link goes down, and gets back, I don't want the laser link get active right away (due to fog), but just after 15 minutes or so.
I've tried to change the ospf timers, but the delay of adding the ospf database to the routing table also affected my wifi redundancy timings.
So I tried 2 separate ospf processes, but that didn't work out as I would like it to be.
Anyone with a thought about this?
You can build a GRE tunnel between the locations and use the ethernet interface layer3 information as the source and destination for the tunnel.
Make sure to enable keepalives in the tunnel in order to detect the link failure.
Once you do that, apply a backup delay on the tunnel interface pointing to the wifi interface.
The wifi interface will remain down as long as the tunnel is up. Once the tunnel goes down, the wifi interface will go up and when the connectivity returns in the tunnel, you can see the delay to the time you desire.
Both interfaces will be up at that time so make sure the wifi interface has a better OSPF cost.