Dell Force10 S55T S55 Configuration Guide FTOS 8.3.5.3 - Page 771

45 Virtual Router Redundancy Protocol (VRRP) c e s Virtual Router Redundancy Protocol (VRRP) is supported on platforms This chapter covers the following information: • VRRP Overview • VRRP Benefits • VRRP Implementation • VRRP Configuration • Sample Configurations Virtual Router Redundancy Protocol (VRRP) is designed to eliminate a single point of failure in a statically routed network. This protocol is defined in RFC 2338 and RFC 3768. VRRP Overview 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 to the next hop IP address. If the MASTER router fails, VRRP begins the election process to choose a new MASTER router and that new MASTER continues routing traffic. VRRP uses the Virtual Router Identifier (VRID) to identify each virtual router configured The IP address of the MASTER router is used as the next hop address for all end stations on the LAN. The other routers represented by IP addresses are BACKUP routers. VRRP packets are transmitted with the virtual router MAC address as the source MAC address. The MAC address is in the following format: 00-00-5E-00-01-{VRID}. The first three octets are unchangeable. The next 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 VRRP routers on a network. Figure 45-1 shows a typical network configuration using VRRP. Instead of configuring the hosts on the network 10.10.10.0 with the IP address of either Router A or Router B as their default router; their default router is the IP Address configured on the virtual router. When any host on the LAN segment wants to access the Internet, it sends packets to the IP address of the virtual router. Virtual Router Redundancy Protocol (VRRP) | 771