3Com S7906E Configuration Manual page 2076

Figure 1-2 Network diagram for VRRP
Host A
Host B
Host C
As shown in Figure 1-2, Router A, Router B, and Router C form a virtual router, which has its own IP
address. Hosts on the Ethernet use the virtual router as the default gateway.
The router with the highest priority of the three routers is elected as the master to act as the gateway,
and the other two are backups.
The IP address of the virtual router can be either an unused IP address on the segment where the
VRRP group resides or the IP address of an interface on a router in the VRRP group. In the latter
case, the router is called the IP address owner.
In a VRRP group, you can configure only one IP address owner.
Status of a router in a VRRP group includes master, backup, and initialize.
VRRP priority
VRRP determines the role (master or backup) of each router in the VRRP group by priority. A router with
a higher priority has more opportunity to become the master.
VRRP priority is in the range of 0 to 255. The greater the number, the higher the priority. Priorities 1 to
254 are configurable. Priority 0 is reserved for special uses and priority 255 for the IP address owner.
When a router acts as the IP address owner, its running priority is always 255. That is, the IP address
owner in a VRRP group acts as the master as long as it works properly.
If two routers are both in the master state and have the same priority, the router with a higher IP address
becomes the master.
Virtual router
Router A
Router B
Network
Router C
1-3