H3C Technologies H3C S10500 Series Switches - Manual (Page 139)

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Assume that Router A is the master and therefore can forward packets to external networks, whereas
Router B and Router C are backups and are thus in the state of listening. If Router A fails, Router B and
Router C elect for a new master to forward packets to hosts on the LAN.
Load sharing
More than one VRRP group can be created on an interface of a router to allow the router to be the master
of one VRRP group but a backup of another at the same time.
In load sharing mode, multiple routers provide services simultaneously. This mode requires two or more
VRRP groups, each of which comprises a master and one or more backups. The masters of the VRRP
groups are assumed by different routers, as shown in Figure 36 .
Figure 36 VRRP in load sharing mode
Host A
Host B
Host C
Router A
Backup
Router B
Backup
Router C
Master
VRRP group 2 VRRP group 3 VRRP group 1
Master
Backup
Backup Backup
Master
Backup
Network
A router can be in multiple VRRP groups and hold a different priority in a different group.
As shown in
Figure 36 , the following VRRP groups are present:
• VRRP group 1—Router A is the master; Router B and Router C are the backups.
• VRRP group 2—Router B is the master; Router A and Router C are the backups.
• VRRP group 3—Router C is the master; Router A and Router B are the backups.
For load sharing among Router A, Router B, and Router C, hosts on the LAN need to be configured to use
VRRP group 1, 2, and 3 as the default gateways respectively. When configuring VRRP priorities, make
sure that each router holds such a priority in each VRRP group that it will take the expected role in the
group.
Configuring VRRP for IPv4
VRRP for IPv4 configuration task list
To form a VRRP group, perform the following configurations on each device in the VRRP group.
Complete these tasks to configure VRRP for IPv4: