Example: Basic VRRP Configuration

As Figure 1 shows, the basic VRRP configuration uses a single VRID (VRID 1). Because R1 is the address owner, it serves as the master router. Router R2 is the backup router. The four end hosts on subnet 1 are configured to use 10.0.0.1/8 as the default router. IP address 10.0.0.1 is associated with VRID 1.

In this example, if R1 becomes unavailable, R2 takes over VRID 1 and its associated IP addresses. Packets sent to IP destinations outside the 10.x.x.x subnet using 10.0.0.1 as the router are then forwarded by R2. Even though R2 assumes R1's forwarding responsibilities, it may or may not process any packet with destination address (DA) 10.0.0.1, depending on the accept-data configuration. When R1 becomes active again, it takes over as the master router and R2 reverts to the backup router.

The VRRP MAC address is always 00-00-5e-00-01-vrid. The valid VRID range is 0x01–0xFF.

Figure 1: Basic VRRP Configuration