ZyXEL Communications ZYWALL USG 2000 Support Notes page 220

ZyWALL USG 2000 Support Notes
L04. Can Link Monitor of Device HA be used in backup VRRP interfaces?
No, the Link monitor is designed only for master device, if the master VRRP interface's link is
down, "Link Monitor" shuts down all of the master's VRRP interfaces except the failure
interface so the backup ZyWALL takes over completely.
L05. Why do both the VRRP interfaces of master ZW USG 2000 and backup ZW
USG 2000 are activated at the same time?
Since the ZWUSG 2000 master sends multicast VRRP announcement to backup ZWUSG
2000 periodically, if the backup ZWUSG 2000 doesn't receive the VRRP announcement, it
will activate its VRRP interfaces.
For the application scenario if the VRRP interface of master and backup ZWUSG 2000
connect to a switch, the switch MUST forward the VRRP multicast to the backup ZWUSG
2000. Otherwise the backup ZyWALL will never receive VRPT announcement. Please ensure
the switch forwards the multicast VRRP announcement (224.0.0.18) by enabling the "Unkown
multicast flodding" option in the switch setting.
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