ZyXEL Communications XGS4700 Series, Manual

Page: 373 / 485

Chapter 41 VRRP
XGS4700-48F User’s Guide
373
41.3.2 VRRP Parameters
This section describes the VRRP parameters.
41.3.2.1 Advertisement Interval
The master router sends out Hello messages to let the other backup routers know
that it is still up and running. The time interval between sending the Hello
messages is the advertisement interval. By default, a Hello message is sent out
every second.
If the backup routers do not receive a Hello message from the master router after
this interval expires, it is assumed that the master router is down. Then the
backup router with the highest priority becomes the master router.
Note: All routers participating in the virtual router must use the same advertisement
interval.
41.3.2.2 Priority
Configure the priority level (1 to 254) to set which backup router to take over in
case the master router goes down. The backup router with the highest priority will
take over. The priority of the VRRP router that owns the IP address(es) associated
with the virtual router is 255.
41.3.2.3 Preempt Mode
If the master router is unavailable, a backup router assumes the role of the
master router. However, when another backup router with a higher priority joins
the network, it will preempt the lower priority backup router that is the master.
Disable preempt mode to prevent this from happening.
By default, a layer 3 device with the same IP address as the virtual router will
become the master router regardless of the preempt mode.