3Com Switch 4800G 24-Port Configuration Manual page 1080

1080 C 87: VRRP C
HAPTER ONFIGURATION
master. The new master takes over the forwarding task to provide services to hosts
on the LAN.
Load balancing
You can create more than one standby group on an interface of a switch, allowing
the switch to be the master of one standby group but a backup of another at the
same time.
In load balancing mode, multiple switches provide services at the same time. This
mode requires two or more standby groups, each of which includes a master and
one or more backups. The masters of the standby groups can be assumed by
different switches, as shown in Figure 323.
Figure 323 VRRP in load balancing mode
Virtual router 1
Host A
Host B
Host C
A switch can be in multiple standby groups and hold a different priority in
different group.
In Figure 323, three standby groups are present:
Standby group 1: Switch A is the master; Switch B and Switch C are the
■
backups.
Standby group 2: Switch B is the master; Switch A and Switch C are the
■
backups.
Standby group 3: Switch C is the master; Switch A and Switch B are the
■
backups.
For load balancing among Switch A, Switch B, and Switch C, hosts on the LAN
need to be configured to use standby group 1, 2, and 3 as the default gateways
respectively. When configuring VRRP priorities, ensure that each switch holds such
a priority in each standby group that it will take the expected role in the group.
Virtual router 2 Virtual router 3
Switch A
Backup
Master Backup
Switch B
Backup
Backup Master
Switch C
Master
Backup Backup
Network