This figure shows a LAN topology in which VRRP is configured so that routers
A and B share the load of being the default gateway for clients 1 through 4.
Routers A and B act as backup virtual routers to one another should either
router fail.
In this example, two virtual routers groups are configured. For virtual
router 1, router A is the owner of IP address 10.0.0.1, and therefore, the
master virtual router for clients configured with that default gateway address.
Router B is the backup virtual router to router A.
For virtual router 2,
router B is the owner of IP address 10.0.0.2 and is the master virtual router
for clients configured with the default gateway IP address of 10.0.0.2. Router
A is the backup virtual router to router B.
Given that the IP address of
the VRRP group is that of a physical interface on one of the group members, the
router owning that address will be the master in the VRRP group. Its priority
is set to 255. Backup router priority values can range from 1 to 254; the
default value is 100.
The master sends the advertisement on multicast
224.0.0.18 on a default interval of 1 second. A VRRP flow message is similar in
concept to an HSRP coup message. A master with a priority of zero triggers a
transition to a backup router. The result is similar to an HSRP resign
message.
The dynamic failover, when the active (master) becomes
unavailable, uses two timers within VRRP: the advertisement interval and the
master-down interval. The advertisement interval is the time interval between
advertisements (seconds). The default interval is 1 second. The master-down
interval is the time interval for backup to declare the master down
(seconds).