Consolidated Platform Configuration Guide, Cisco Ios Release 15.2(4)E (Catalyst 2960-X Switches - Cisco Catalyst 2960 series Configuration Manual

Information About Embedded Event Manager
Embedded Event Manager Policies Using the Cisco IOS CLI" or the "Writing Embedded Event Manager
Policies Using Tcl" modules. EEM contains the following event detectors.
Application-Specific Event Detector
The application-specific event detector allows any Embedded Event Manager policy to publish an event.
When an EEM policy publishes an event it must use an EEM subsystem number of 798 with any event type.
If an existing policy is registered for subsystem 798 and a specified event type, a second policy of the same
event type will trigger the first policy to run when the specified event is published.
CLI Event Detector
The CLI event detector screens command-line interface (CLI) commands for a regular expression match.
When a match is found, an event is published. The match logic is performed on the fully expanded CLI
command after the command is successfully parsed and before it is executed. The CLI event detector supports
three publish modes:
• Synchronous publishing of CLI events--The CLI command is not executed until the EEM policy exits,
and the EEM policy can control whether the command is executed. The read/write variable, _exit_status,
allows you to set the exit status at policy exit for policies triggered from synchronous events. If
_exit_status is 0, the command is skipped, if _exit_status is 1, the command is run.
• Asynchronous publishing of CLI events--The CLI event is published, and then the CLI command is
executed.
• Asynchronous publishing of CLI events with command skipping--The CLI event is published, but the
CLI command is not executed.
Counter Event Detector
The counter event detector publishes an event when a named counter crosses a specified threshold. There are
two or more participants that affect counter processing. The counter event detector can modify the counter,
and one or more subscribers define the criteria that cause the event to be published. After a counter event has
been published, the counter monitoring logic can be reset to start monitoring the counter immediately or it
can be reset when a second threshold--called an exit value--is crossed.
Custom CLI Event Detector
The custom CLI event detector publishes an event to add and enhance existing CLI command syntax. When
the special parser characters Tab, ? (question mark), and Enter are entered, the parser sends the input to the
custom CLI event detector for processing. The custom CLI event detector then compares this input against
registered strings to determine if this is a new or enhanced CLI command. Upon a match the custom CLI
event detector takes appropriate actions, such as displaying help for the command if ? is entered, displaying
the entire command if Tab is entered, or executing the command if Enter was entered. If a match does not
occur, the parser regains control and processes the information as usual.
Enhanced Object Tracking Event Detector
The enhanced object tracking (EOT) event detector publishes an event when the status of a tracked object
changes. Object tracking was first introduced into the Hot Standby Router Protocol (HSRP) as a simple
tracking mechanism that allowed you to track the interface line-protocol state only. If the line-protocol state
of the interface went down, the HSRP priority of the device was reduced, allowing another HSRP device with
a higher priority to become active.

Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)

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