Configuring VRRP VRRP Configuration Overview
OmniSwitch AOS Release 8 Network Configuration Guide December 2017 page 23-12
-> vrrp 6 4 admin-state disable
-> vrrp 6 4 priority 50
-> vrrp3 10 5 admin-state disable
-> vrrp3 10 5 priority 50
In this example, VRRPv2 virtual router 6 and VRRPv3 virtual router 10 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 IPv4 or IPv6 address. Setting the priority value to 50 would typically provide
a router with a lower priority in the VRRPv2 or VRRPv3 network.
Setting Preemption for Virtual Routers
When a 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 their priority values are very nearly equal, the
skew time may not be sufficient to overcome delays caused by network traffic loads. This may cause a
lower priority backup to 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.
If all virtual routers have the preempt mode enabled, the virtual router with the highest priority will
become the master. If the master router goes down, the highest priority backup router will become the
master. If the previous master or any other virtual router comes up with the preempt mode enabled and has
a higher priority value, this router will become the new master.
By default virtual routers are allowed to preempt each other; that is, 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.
To prevent a router with a higher priority value from automatically taking control from a master router
with a lower priority value, disable the preempt mode for the higher priority router. This is done by using
the no preempt keywords with the vrrp or vrrp3 command option. For example:
-> vrrp 6 4 admin-state disable
-> vrrp 6 4 no preempt
-> vrrp3 10 5 admin-state disable
-> vrrp3 10 5 no preempt
In this example, VRRPv2 virtual router 6 and VRRPv3 virtual router 10 are disabled. (If you are
modifying an existing virtual router, the virtual router must be disabled before it may be modified.) The
preempt mode is then disabled for the virtual routers. If virtual router 6 and 10 take over for an unavailable
router, another router with a higher priority will not be able to preempt them. For more information about
priority, see “Configuring Virtual Router Priority” on page 23-11.
Note. In certain cases, this may not be a desirable behavior, as when the original master comes back and
immediately causes all the traffic to switch back to it.
Note. The virtual router that owns the IP 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 Next Page
Loading...
Need help?
General
