I have a central location and four remote locations with a router at each location. I will have private leased lines for main WAN connectivity. I will also be using IPsec over GRE for VPN backups from each location to the central location over the public IP cloud. My plan is to configure EIGRP on each of the routers as well as "floating static routes" for the GRE tunnels.
My questions are:
1. Will this work to ensure that the VPNs are only used in the event that the main WAN connectivity goes down and that the VPNs are not used when the main WAN connectivity comes back up?
2. If the floating routes are configured for the GRE tunnels, will this prevent the EIGRP protocol from using the GRE tunnels as part of its topology?
3. Should this be the other way around (meaning should I configure static routes for the main WAN links and EIGRP for the GRE tunnels?)
4. If I do configure it as mentioned in question 3, won't the static routes have to be manually re-added to the table when the WAN links come back up (as opposed to GRE tunnels which are always considered up so the static routes would never be removed from the table)?
The idea is to get the VPN backups to work transparently without any manual adjustments to the router config. Any thoughts would be greatly appreciated. Thank you.