VRRPv3 Configuration Overview
Configuring VRRP
page 22-22
OmniSwitch AOS Release 7 Network Configuration Guide
June 2013
which backup routers will take over for the master. If priority values are the same, any backup will take
over for master.
Note that the switch sets the priority value to zero in the last VRRPv3 advertisement packet before a
master router is disabled (see
“Enabling/Disabling a VRRPv3 Virtual Router” on page 22-23
).
Also, if a router is the IPv6 address owner and the priority value is not set to 255, the switch will set its
priority to 255 when the router is enabled.
To set the priority, use the
command with the
priority
keyword and the desired value. For example:
-> vrrp3 6 4 admin-state disable
-> vrrp3 6 4 priority 50
In this example, VRRPv3 virtual router 6 is disabled. (If you are modifying an existing virtual router, the
virtual router must be disabled before it may be modified.) The virtual router priority is then set to 50. The
priority value is relative to the priority value configured for other virtual routers backing up the same IPv6
address. Changing the default priority value and setting it to 50 would typically provide a router with
lower priority in the VRRPv3 network.
Setting Preemption for VRRPv3 Virtual Routers
When a VRRPv3 master virtual router becomes unavailable (goes down for whatever reason), a backup
router will take over. When there is more than one backup router and if the backup routers have priority
values that are very nearly equal, the skew time may not be sufficient to overcome delays caused by
network traffic loads and a lower priority backup may assume control before a higher priority backup. But
when the preempt mode is enabled the higher priority backup router will detect this and assume control.
By default VRRPv3 virtual routers are allowed to preempt each other; that is, if the virtual router with the
highest priority will take over if the master router becomes unavailable. The preempt mode may be
disabled so that any backup router that takes over when the master is unavailable will not then be
preempted by a backup with a higher priority.
Note.
The VRRPv3 virtual router that owns the IPv6 address(es) associated with the physical router
always becomes the master router if is available, regardless of the preempt mode setting and the priority
values of the backup routers.
To disable preemption for a VRRPv3 virtual router, use the
command with the
no preempt
keywords. For example:
-> vrrp3 6 4 admin-state disable
-> vrrp3 6 4 no preempt
In this example, virtual router 6 is disabled. (If you are modifying an existing virtual router, the virtual
router must be disabled before it may be modified.) The virtual router is then configured to disable
preemption. If this virtual router takes over for an unavailable router, a router with a higher priority will
not be able to preempt it. For more information about priority, see
“Configuring the VRRPv3 Virtual