Cisco Systems 3560X, 3750-X, WSC3750X48TS Embedded Event Manager Environment Variables , EEM 3.2

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 36 Configuring Embedded Event Manager Understanding Embedded Event Manager
You use EEM to write and implement your own policies using the EEM policy tool command language
(TCL) script. When you configure a TCL script on the master switch and the file is automatically sent
to the member switches. The user-defined TCL scripts must be available in the member switches so that
if the master switch changes, the TCL scripts policies continue to work.
Cisco enhancements to TCL in the form of keyword extensions facilitate the development of EEM
policies. These keywords identify the detected event, the subsequent action, utility information, counter
values, and system information.
For complete information on configuring EEM policies and scripts, see the Cisco IOS Network Management
Configuration Guide, Release 12.4T.
Embedded Event Manager Environment Variables
EEM uses environment variables in EEM policies. These variables are defined in a EEM policy tool
command language (TCL) script by running a CLI command and the event manager environment
command.
User-defined variables
Defined by the user for a user-defined policy.
• Cisco-defined variables
Defined by Cisco for a specific sample policy.
• Cisco built-in variables (available in EEM applets)
Defined by Cisco and can be read-only or read-write. The read-only variables are set by the system
before an applet starts to execute. The single read-write variable, _exit_status, allows you to set the
exit status for policies triggered from synchronous events.
Cisco-defined environment variables and Cisco system-defined environment variables might apply to
one specific event detector or to all event detectors. Environment variables that are user-defined or
defined by Cisco in a sample policy are set by using the event manager environment global
configuration command. You must defined the variables in the EEM policy before you register the
policy.
For information about the environmental variables that EEM supports, see the Cisco IOS Network
Management Configuration Guide, Release 12.4T.
EEM 3.2
EEM 3.2 is supported in Cisco IOS Release 12.2(52)SE and later and introduces these event detectors:
• Neighbor Discovery—Neighbor Discovery event detector provides the ability to publish a policy to
respond to automatic neighbor detection when:
– a Cisco Discovery Protocol (CDP) cache entry is added, deleted, or updated.
– a Link Layer Discovery Protocol (LLDP) cache entry is added, deleted or updated.
– an interface link status changes.
– an interface line status changes.
• Identity—Identity event detector generates an event when AAA authorization and authentication is
successful, when failure occurs, or after normal user traffic on the port is allowed to flow.