We have a core network that has L2L tunnels with several spokes. Several spokes are 8.4 or higher and one spoke is 8.2.5.
The core has a backup Internet link -- let's call it Backup. Goal is to maintain L2L tunnels to the spokes if the primary internet on the core goes down.
On the core side, I've configured NAT to the (inside,Backup), and an access list to allow Backup_access_in.
On the spoke side, I've configured additional tunnel groups to the Backup on the Core. What else is required? Additional crypto maps?