VRRP and Neighbor Discovery for IPv6

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

  • Determine the link-layer address of neighbors

  • Verify that a neighbor is reachable

  • Track neighbor (local) routers

Neighbor Discovery enables functions such as:

  • Router and neighbor solicitations and discovery

  • Detecting address changes for devices

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

  • Duplicate address detection (DAD)

  • Router Advertisement processing

  • Neighbor reachability

  • 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 a minimum of VRRPv3 traffic.