In case of geographic node separation, each node's data center router must set up IPSec/GRE VPN tunnels to the branch office.
The data center router is set up to route the traffic to the branch offices via the tunnels. The Branch Office's router is set up (using metrics) to:
primarily send all IP traffic to each of the data centers.
if this doesn't work, set up a backup access link to the backup data center based on the destination IP address.
Parent topic: Survivability Overview
General Characteristics of the SBC Branch Office Solution