VRRP and neighbor discovery for IPv6

Neighbor Discovery (ND) is the IPv6 equivalent of the IPv4 ARP for layer 2 address resolution, and uses IPv6 ICMP messages to do the following:

• Determine the link-layer address of neighbors on the same VLAN interface.

• Verify that a neighbor is reachable.

• Track neighbor (local) routers.

Neighbor Discovery enables functions such as the following:

• Router and neighbor solicitations and discovery

• Detecting address changes for devices on a VLAN

• Identifying a replacement for a router or router path that has become unavailable

• Duplicate address detection (DAD)

• Router Advertisement processing

• Neighbor reachability

• Autoconfiguration of unicast addresses

• Resolution of destination addresses

• Changes to link-layer addresses.

An instance of Neighbor Discovery is triggered on a device when a new or changed IPv6 address is detected. VRRPv3 provides a faster failover to a backup router by not using standard ND procedures. A failover to a backup router can occur in approximately three seconds without any interaction with hosts and with a minimum of VRRPv3 traffic.