3Com S7906E - Switch, Configuration Manual

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Monitor the master on a backup. If there is a fault on the master, the backup working in the mode
switches to the master immediately to maintain normal communication.
For details of Track object tracking, refer to Track Configuration in the High Availability Volume .
VRRP Application (Taking IPv4-Based VRRP for Example)
Master/backup
In master/backup mode, only one router, the master, forwards packets. When the master fails, a new
master is elected from the original backups. This mode requires only one VRRP group, in which each
router holds a different priority and the one with the highest priority becomes the master, as shown in
Figure 1-5 .
Figure 1-5 VRRP in master/backup mode
At the beginning, 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. The new master takes over the forwarding task to
provide services to hosts on the LAN.
Load sharing
You can create more than one VRRP group on an interface of a router, and 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 at the same time. This mode requires two or
more VRRP groups, each of which includes a master and one or more backups. The masters of the
VRRP groups are assumed by different routers, as shown in Figure 1-6 .