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Resilient LLB deployment scenario

In the following diagram, there are two networks: 30.30.30.0 and 30.30.31.0. 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 the opposite way. All traffic with the destination IP specified as 30.30.30.30 is sent through Router1-vip and traffic with the destination IP specified as 30.30.31.31 is sent through Router2-vip.

Figure 1. Resilient LLB Deployment Setup

LLB deployment setup

Note: If your ISP has provided an IPv6 address, replace the IPv4 service with an IPv6 service in the preceding figure.

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 30.30.30.30 is also sent through ISP2.

Figure 2. Resilient LLB Deployment Scenario

LLB deployment scenario

Note: If your ISP has provided an IPv6 address, replace the IPv4 service with an IPv6 service in the preceding figure.

Resilient LLB deployment scenario

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