H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 17)

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state of the monitored track entry is negative and the priority of the router decreases by a specified
value. Then, a higher priority router in the VRRP group becomes the master to maintain the proper
communication between the hosts in the LAN and external networks.
• Monitor the master on a backup. When the master fails, the backup immediately preempts as the
master to maintain normal communication.
NOTE:
For more information about track entries, see "Configuring track."
VRRP application
Master/backup
In master/backup mode, only the master forwards packets. When the master fails, a new master is
elected from the 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 4 .
Figure 4 VRRP in master/backup mode
Assume that Router A is acting as the master to forward packets to external networks, and Router B and
Router C are backups in listening state. When Router A fails, Router B and Router C elect for a new
master to forward packets for 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 5 .