Understanding Enhanced Object Tracking - Cisco Catalyst 3750-E Software Configuration Manual

Configuring Enhanced Object Tracking
This chapter describes how to configure enhanced object tracking on the Catalyst 3750-E or 3560-E
switch. This feature provides a more complete alternative to the Hot Standby Routing Protocol (HSRP)
tracking mechanism. which allows you to track the line-protocol state of an interface. If the line protocol
state of an interface goes down, the HSRP priority of the interface is reduced and another HSRP device
with a higher priority becomes active. The enhanced object tracking feature separates the tracking
mechanism from HSRP and creates a separate, standalone tracking process that can be used by processes
other than HSRP. This allows tracking other objects in addition to the interface line-protocol state. A
client process, such as HSRP, can register an interest in tracking objects and request notification when
the tracked object changes state.This feature increases the availability and speed of recovery of a routing
system and decreases outages and outage duration.
Unless otherwise noted, the term switch refers to a Catalyst 3750-E or 3560-E standalone switch and to
a Catalyst 3750-E switch stack. For additional information about Enhanced Object Tracking, see the
Enhanced Object Tracking" feature guide located under Cisco IOS Software Release 12.2T, Feature
Guides.
The chapter includes these sections:
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Understanding Enhanced Object Tracking

Each tracked object has a unique number that is specified in the tracking command-line interface (CLI).
Client processes use this number to track a specific object. The tracking process periodically polls the
tracked object for value changes and sends any changes (as up or down values) to interested client
processes, either immediately or after a specified delay. Several clients can track the same object, and
can take different actions when the object changes state.
You can also track a combination of objects in a list by using either a weight threshold or a percentage
threshold to measure the state of the list. You can combine objects using Boolean logic. A tracked list
with a Boolean "AND" function requires that each object in the list be in an up state for the tracked object
to be up. A tracked list with a Boolean "OR" function needs only one object in the list to be in the up
state for the tracked object to be up.
OL-9775-08
Understanding Enhanced Object Tracking, page 44-1
Configuring Enhanced Object Tracking Features, page 44-2
Monitoring Enhanced Object Tracking, page 44-12
C H A P T E R
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
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