In the following diagram, there are two networks: 220.127.116.11 and 18.104.22.168. Link load balancing is configured based on the destination IP address. Two routes are configured with gateways Router1-vip and Router2-vip, respectively. Router1-vip is configured as a backup to Router2-vip and vice versa. All traffic with the destination IP specified as 22.214.171.124 is sent through Router1-vip and traffic with the destination IP specified as 126.96.36.199 is sent through Router2-vip.
However, if any one of the gateways (Router1-vip or Router2-vip) is DOWN, traffic is routed through the backup router. In the following diagram, Router1-vip for ISP1 is DOWN, so all traffic with the destination IP specified as 188.8.131.52 is also sent through ISP2.