Editing Virtual Router Redundancy Protocol (section)

==Implementation==
A virtual router must use {{MACaddr|00-00-5E-00-01-XX}} as its [[media access control]] (MAC) address. The last byte of the address (XX) is the virtual router identifier (VRID), which is different for each virtual router in the network. This address is used by only one physical router at a time, and it will reply with this [[MAC address]] when an [[Address Resolution Protocol|ARP]] request is sent for the virtual router's IP address.

Physical routers within the virtual router must communicate within themselves using packets with [[Multicast address|multicast]] [[Internet Protocol|IP]] address {{IPaddr|224.0.0.18}} and [[List of IP protocol numbers|IP protocol number]] 112{{Ref RFC|5798}} for IPv4, or {{IPaddr|ff02::12}} and IP protocol number 112 for IPv6{{Ref RFC|5798}}.

Routers backing up a virtual router have a priority between 1 and 254, and the router with the highest priority will become the primary/active. The default priority is 100; for the MAC address owner, the priority is always 255.