Brocade Communications Systems ICX 7250 series, Configuration Manual

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The following example shows how to configure Ethernet interface 1/2/4 on virtual router 1 to be tracked; if the interface fails, the VRRP
priority of the device becomes 20, forcing a negotiation for a new master device.
device# configure terminal
device(config)# router vrrp
device(config)# interface ethernet 1/1/6
device(config-if-e1000-1/1/6)# ip address 10.53.5.1/24
device(config-if-e1000-1/1/6)# ip vrrp vrid 1
device(config-if-e1000-1/1/6-vrid-1)# track-port ethernet 1/2/4 priority 20
VRRP backup preemption
Preemption of a backup VRRP device acting as a master device is allowed when another backup device has a higher priority.
By default, preemption is enabled for VRRP. In VRRP, preemption allows a backup device with the highest priority to become the master
device when the master (also the owner) device goes offline. If another backup device is added with a higher priority, it will assume the
role of the master VRRP device. In some larger networks there may be a number of backup devices with varying levels of priority, and
preemption can cause network flapping. To prevent the flapping, disable preemption.
NOTE
If preemption is disabled for VRRP, the owner device is not affected because the owner device always preempts the active
master. When the owner device is online, the owner device assumes the role of the master device regardless of the setting for
the preempt parameter.
In VRRP-E, preemption is disabled by default. In situations where a new backup device is to be added with a higher priority, preemption
can be enabled. There are no owner devices in VRRP-E to automatically preempt a master device.
Disabling VRRP backup preemption
VRRP backup preemption can be disabled to avoid route flapping when a backup VRRP device that is acting as the master device could
be preempted by another backup device with a higher priority value.
A VRRP or VRRP-E session must be globally enabled using the router vrrp or router vrrp-extended command in global configuration
mode.
Preemption is enabled by default for VRRP and VRRP-E, but if several devices come back online with higher priorities than the original
backup device, route flapping can occur as these devices preempt each other. The following steps can be used when you want to avoid a
backup device acting as the master from being preempted by another backup device with a higher priority value.
1. Enter interface configuration mode.
device(config)# interface ethernet 1/1/5
2. Enter the IP address for the interface to be used for the virtual router ID (VRID).
device(config-if-e1000-1/1/5)# ip address 10.53.5.3/24
3. Enter the following command to enter the appropriate VRRP VRID mode.
device(config-if-e1000-1/1/5)# ip vrrp vrid 1
VRRP backup preemption
Brocade FastIron Layer 3 Routing Configuration Guide
440 53-1003903-04