CHAPT ER
44-1
Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
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Configuring Enhanced Object Tracking
This chapter describes how to configure enhanced object tracking on the Catalyst 3750 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 standalone switch and to a switch stack.
For more information about enhanced object tracking and the commands used to configure it:
http://www.cisco.com/en/US/docs/ios/ipapp/configuration/guide/ipapp_eot.html
The chapter has these sections:
•Understanding Enhanced Object Tracking, page44-1
•Configuring Enhanced Object Tracking Features, page44-2
•Monitoring Enhanced Object Tracking, page 44-13

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.