Virtual Router Redundancy Protocol (VRRP) | 94949Virtual Router Redundancy Protocol (VRRP)Virtual Router Redundancy Protocol (VRRP) is supported on platforms: e c s z .This chapter covers the following information:• VRRP Overview• VRRP Benefits• VRRP Implementation• VRRP Configuration• Sample ConfigurationsVRRP OverviewVirtual Router Redundancy Protocol (VRRP) is designed to eliminate a single point of failure in astatically routed network.VRRP specifies a MASTER router that owns the next hop IP and MAC address for end stations on a LAN.The MASTER router is chosen from the virtual routers by an election process and forwards packets sent tothe next hop IP address. If the MASTER router fails, VRRP begins the election process to choose a newMASTER router and that new MASTER continues routing traffic.VRRP uses the Virtual Router Identifier (VRID) to identify each virtual router configured The IP addressof the MASTER router is used as the next hop address for all end stations on the LAN. The other routersrepresented by IP addresses are BACKUP routers.VRRP packets are transmitted with the virtual router MAC address as the source MAC address. The MACaddress is in the following format: 00-00-5E-00-01-{VRID}. The first three octets are unchangeable. Thenext two octets (00-01) indicate the address block assigned to the VRRP protocol, and are unchangeable.The final octet changes depending on the VRRP Virtual Router Identifier and allows for up to 255 VRRProuters on a network.Figure 49-1 shows a typical network configuration using VRRP. Instead of configuring the hosts on thenetwork 10.10.10.0 with the IP address of either Router A or Router B as their default router; their defaultrouter is the IP Address configured on the virtual router. When any host on the LAN segment wants toaccess the Internet, it sends packets to the IP address of the virtual router.
