VRRP in Active/Standby Mode
Active/Standby is the basic VRRP working mode, as shown in Figure 7-4. In active/standby mode, a virtual router consists of one master and multiple backups.
RouterA is the master and forwards service packets. RouterB and RouterC are backups and do not forward service packets. RouterA periodically sends VRRP Advertisement packets to RouterB and RouterC, notifying other switches that RouterA is working properly. If RouterA is faulty, a new master is selected from RouterB and RouterC based on their priorities. The new master then takes over traffic.
After RouterA recovers, it becomes the master in preemption mode. In non-preemption mode, RouterA remains in Backup state.