Allied Telesis AT-S63 - Manual (Page 367)

AT-S63 Management Software Features Guide
Section VII: Routing 367
Port Monitoring
Port monitoring is the process of detecting the failure of ports that are part
of a VLAN that a virtual router is running over. If a port fails or is disabled,
the VRRP priority is reduced by the stepvalue or by an amount that reflects
the proportion of the VLAN’s ports that are out of service. If the switch is
the master and a backup switch has a higher priority, the backup switch
preempts the master and becomes the new master.
Note the following about port monitoring:
ˆ You can delete an IP interface if it is a monitored interface, because
VRRP is only monitoring the state of the interface and does not require
that the interface have an IP address.
ˆ A VLAN cannot be destroyed if it is a monitored interface of a VRRP.
To destroy a VLAN, you must first destroy the monitored interface.