Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 111)

The default track priority for all track ports is 5. You can change the default track priority or override the
default for an individual track port.
• To change the default track priority, use the backup priority value track-priority value command,
described below.
• To override the default track priority for a specific track port, use the track-port command. Refer to
Specifying a track port setting on page 111.
To change the track priority, enter a command such as the following at the configuration level for the
VRID.
device(config-vlan-200-vrid-1)#backup priority 100 track-priority 2
Syntax: [no] backup [ priority value ] [ track-priority value ]
Specifying a track port setting
You can configure the VRID on one interface to track the link state of another interface on the device.
This capability is useful for tracking the state of the exit interface for the path for which the VRID is
providing redundancy. Refer to
VSRP priority calculation on page 96.
To configure a VRID to track an interface, enter a command such as the following at the configuration
level for the VRID.
device(config-vlan-200-vrid-1)#track-port ethernet 2/4
Syntax: [no] track-port ethernet [ slotnum/ ] portnum | ve num [ priority num ]
The priority num parameter changes the VSRP priority of the interface. If this interface goes down, the
VRID VSRP priority is reduced by the amount of the track port priority you specify here.
NOTE
The priority num option changes the priority of the specified interface, overriding the default track port
priority. To change the default track port priority, use the backup track-priority num command.
Disabling or re-enabling backup pre-emption setting
By default, a Backup that has a higher priority than another Backup that has become the Master can
preempt the Master, and take over the role of Master. If you want to prevent this behavior, disable
preemption.
Preemption applies only to Backups and takes effect only when the Master has failed and a Backup has
assumed ownership of the VRID. The feature prevents a Backup with a higher priority from taking over
as Master from another Backup that has a lower priority but has already become the Master of the
VRID.
Preemption is especially useful for preventing flapping in situations where there are multiple Backups
and a Backup with a lower priority than another Backup has assumed ownership, because the Backup
with the higher priority was unavailable when ownership changed.
If you enable the non-preempt mode (thus disabling the preemption feature) on all the Backups, the
Backup that becomes the Master following the disappearance of the Master continues to be the Master.
The new Master is not preempted.
To disable preemption on a Backup, enter a command such as the following at the configuration level
for the VRID.
device(config-vlan-200-vrid-1)#non-preempt-mode
Specifying a track port setting
FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide 111
53-1003086-04