Understanding Enhanced Object Tracking - Cisco ME 3400 Software Configuration Manual

Configuring Enhanced Object Tracking
This chapter describes how to configure enhanced object tracking on the Cisco ME 3400 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 or Gateway Local Balancing Protocol (GLBP), 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.
This feature is supported only when the metro IP access or metro access image is running on the switch.
For more information about enhanced object tracking and the commands used to configure it, see this
URL:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a00801541be.
html
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-9639-07
Understanding Enhanced Object Tracking, page 40-1
Configuring Enhanced Object Tracking Features, page 40-2
Monitoring Enhanced Object Tracking, page 40-12
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