Configuring VRRP and VRRPE
December 2005 © Foundry Networks, Inc. 22 - 17
The <num> parameter specifies the message interval and can be from 60 – 3600 seconds. The default is 60
seconds.
The syntax is the same for VRRP and VRRPE.
Track Port
You can configure the VRID on one interface to track the link state of another interface on the Layer 3 Switch. This
capability is quite useful for tracking the state of the exit interface for the path for which the VRID is providing
redundancy. See “Track Ports and Track Priority” on page 22-5.
To configure 1/6 on Router1 to track interface 2/4, enter the following commands:
Router1(config)# inter e 1/6
Router1(config-if-1/6)# ip vrrp vrid 1
Router1(config-if-1/6-vrid-1)# track-port e 2/4
Syntax: track-port ethernet [<slotnum>/]<portnum> | ve <num>
The syntax is the same for VRRP and VRRPE.
Track Priority
When you configure a VRID to track the link state of other interfaces, if one of the tracked interface goes down, the
software changes the VRRP or VRRPE priority of the VRID interface.
• For VRRP, the software changes the priority of the VRID to the track priority, which typically is lower than the
VRID priority and lower than the VRID’s priorities configured on the Backups. For example, if the VRRPE
interface’s priority is 100 and a tracked interface with track priority 60 goes down, the software changes the
VRRPE interface’s priority to 60.
• For VRRPE, the software reduces the VRID priority by the amount of the priority of the tracked interface that
went down. For example, if the VRRPE interface’s priority is 100 and a tracked interface with track priority 60
goes down, the software changes the VRRPE interface’s priority to 40. If another tracked interface goes
down, the software reduces the VRID’s priority again, by the amount of the tracked interface’s track priority.
The default track priority for a VRRP Owner is 2. The default track priority for Backups is 1.
You enter the track priority as a parameter with the owner or backup command. See “Track Port” on page 22-17.
Syntax: owner [track-priority <value>]
Syntax: backup [priority <value>] [track-priority <value>]
The syntax is the same for VRRP and VRRPE.
Backup Preempt
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.
NOTE: In VRRP, regardless of the setting for the preempt parameter, the Owner always becomes the Master
again when it comes back online.
To Next Page
Loading...
Need help?
General
