Duplicate address detection (DAD)

Duplicate Address Detection verifies that a configured unicast IPv6 address is unique before it is assigned to a VLAN interface. When the owner router fails, the backup VRRP router assumes the master role. When the owner router becomes operational, DAD will fail as there is a backup VRRP router in the master role that responds to the DAD request. To avoid this, virtual routers that are in owner mode (priority = 255) will not send DAD requests for the VLAN interface on which the owner VR is configured.