R2511-HP MSR Router Series High Availability Configuration Guide(V5)

61
Virtual MAC address assignment
In a load balanced VRRP group, the master assigns virtual MAC addresses to the member routers and
answers the ARP requests or ND requests from different hosts. The backup routers do not answer the ARP
requests or ND requests from the hosts.
In an IPv4 network, a load-balanced VRRP group works as follows:
1. The master assigns virtual MAC addresses to all members, including itself. This example assumes
that the virtual IP address of the VRRP group is 10.1.1.1/24, Router A is the master, and Router B
is the backup. Router A assigns 000f-e2ff-0011 to itself and 000f-e2ff-0012 to Router B.
Figure 24 Virtual MAC address assignment
2. When an ARP request arrives, the master (Router A) selects a virtual MAC address based on the
load balancing algorithm to answer the ARP request. In this example, Router A returns the virtual
MAC address of itself in response to the ARP request from Host A. It returns the virtual MAC
address of Router B in response to the ARP request from Host B (see Figure 25).