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Configuring the SNMP Server Event Manager

The SNMP server event manager works in conjunction with the Event MIB (RFC 2981). The purpose of this application is to allow many management functions (for example, fault detection, configuration management, accounting management, and performance management). These functions are traditionally performed by the network management station. However, by using the SNMP server event manager, you can distribute some of these functions to E-series routers and automate them.

Event MIB Purpose

The rapid growth of networks has made it impractical to directly manage networks from a single network management station (NMS). This brought about a need for a model that both automated and distributed event management. The goal was to allow devices to monitor themselves and other devices, and to take action under certain conditions.

The Event MIB (RFC 2981) defines a method for creating trigger conditions, testing those conditions, and determining which action to take when a trigger meets those conditions.

The Event MIB allows you to define test conditions for object integers that are accessible in the agent, making it possible to monitor any aspect of a device without defining specific notifications and complicating the agent definition. In this model, because devices have the ability to monitor themselves or other devices, the processing is distributed throughout the network. Also, sending the information only to the NMS that uses an event model reduces both network overhead and processing drain on the NMS.

Event MIB Structure

The Event MIB has three major parts: the trigger table, the objects table, and the event table. These tables also contain subordinate MIB tables that contain more detailed information about the trigger tests.

Trigger Table

The trigger table (mteTriggerTable) lists any currently-defined trigger conditions. Triggers fall into three categories—existence, Boolean, and threshold.

An existence trigger tests for the existence of a MIB object instance; you can specify that the trigger occur by either the appearance, disappearance, or change in value of a MIB instance.

A Boolean trigger tests whether the value of a MIB object (base syntax integer) is equal, unequal, greater than, less than, less than or equal to, or greater than or equal to some defined value.

A threshold trigger verifies a MIB object (base syntax integer) in relation to either a rising threshold value, falling threshold value, or both.

You can configure both Boolean and threshold tests to trigger on an absolute value or a delta value over a determined polling interval.

Subordinate MIB tables exist within the trigger section of each type of trigger test. In other words, each type of trigger (existence, threshold, and Boolean) contains a table that stores added information about that type of trigger test.

For example, a trigger entry of a specific type of test in the mteTriggerTable creates a linked entry in the appropriate subtable. In turn, this subtable contains more specific information about the specific test.

A delta table also exists within the trigger tables. This table stores information about any delta values based on any Boolean and threshold triggers. The delta table stores a MIB object that indicates whether any discontinuities occurred for any delta trigger (for example, a router reset).

NOTE: When determining discontinuity, the MIB object must be a time-based counter or number. When a polling interval expires and the event agent (router) needs to perform a delta calculation, it first checks the discontinuity MIB object for that trigger. If a discontinuity occurs, the agent does not perform the test for that trigger until the next polling interval.


Objects Table

The objects table (mteObjectsTable) defines objects that you want to add to event messages. In other words, you can create a list of user-specified objects and bind them to a trigger event. This can provide a snapshot of other values on a router when the trigger occurs. You can bind objects to a specific trigger, a type of test (for example, existence or Boolean tests), or a type of event (for example, rising or falling events).

NOTE: This release does not support the objects table.


Event Table

The event table (mteEventTable) defines what action you want the device to take when a trigger occurs. This action can be in the form of a notification, setting a specified MIB object, or both. The results of these actions are controlled within two subordinate MIB tables—notification and set.

Notifications (mteNotifications), or traps, define what the router sends when an event occurs. These traps include the following:

Sets define certain modifications to other MIB objects based on a particular event.

Configuration Tasks

To configure the SNMP server event manager:

  1. Access the SNMP server management event application.
  2. host1(config)#snmp-server management-event
    
    host1(config-mgmtevent)#
    
    
    

    NOTE: You must create a management event instance for each virtual router.

  3. (Optional) Specify the maximum number of trigger entries that you want the virtual router to support.
  4. host1(config-mgmtevent)#resource 275
    
    
    
  5. Create an event for each trap notification (mteTriggerFailure, mteTriggerFalling, or mteTriggerRising) that you want to use by specifying an event owner and event name.
  6. host1(config-mgmtevent)#event sysadmin failuretrigger
    
    host1(config-mgmtevent-event)#exit
    
    host1(config-mgmtevent)#event sysadmin fallingtrigger
    
    host1(config-mgmtevent-event)#exit
    
    host1(config-mgmtevent)#event sysadmin risingtrigger
    
    host1(config-mgmtevent-event)#exit
    
    
    

    NOTE: You must create a separate event for each trap notification that you want to use. However, you can specify the trap notification and enable the trap before exiting the event context.

  7. Define each event to send a trap notification (mteTriggerFailure, mteTriggerFalling, and mteTriggerRising).
  8. host1(config-mgmtevent)#event sysadmin failuretrigger
    
    host1(config-mgmtevent-event)#notification id mteTriggerFailure
    
    host1(config-mgmtevent-event)#exit
    
    host1(config-mgmtevent)#event sysadmin fallingtrigger
    
    host1(config-mgmtevent-event)#notification id mteTriggerFalling
    
    host1(config-mgmtevent-event)#exit
    
    host1(config-mgmtevent)#event sysadmin risingtrigger
    
    host1(config-mgmtevent-event)#notification id mteTriggerRising
    
    host1(config-mgmtevent-event)#exit
    
    
    

    NOTE: The mteTriggerFailure notification is a global value. Once you create a failure event notification, it is automatically bound to every trigger with the same owner. If a failure occurs, and the trigger owner and the event owner are the same, the router sends the trap.

  9. Enable the event, and exit the event configuration level.
  10. host1(config-mgmtevent)#event sysadmin failuretrigger
    
    host1(config-mgmtevent-event)#enable
    
    host1(config-mgmtevent-event)#exit
    
    host1(config-mgmtevent)#event sysadmin fallingtrigger
    
    host1(config-mgmtevent-event)#enable
    
    host1(config-mgmtevent-event)#exit
    
    host1(config-mgmtevent)#event sysadmin risingtrigger
    
    host1(config-mgmtevent-event)#enable
    
    host1(config-mgmtevent-event)#exit
    
    host1(config-mgmtevent)#
    
    
    

    NOTE: Once enabled, you cannot edit an event or trigger configuration. To change an enabled event or trigger, you must delete it and re-create it.

  11. Define the trigger that you want to use for an event by specifying a trigger owner and trigger name.
  12. host1(config-mgmtevent)#trigger george trigger1
    
    host1(config-mgmtevent-trigger)#
    
    
    
  13. Specify a MIB object to sample.
  14. host1(config-mgmtevent-trigger)#sample value-id 1.3.6.1.2.1.60.1.2.1.1.7
    
    
    
  15. Specify the frequency (in seconds) at which you want the sampling to occur.
  16. host1(config-mgmtevent-trigger)#frequency 100
    
    
    

    NOTE: Unless you specify that you want to perform delta sampling, the values are absolute.

  17. (Optional) Specify that you want to perform delta sampling on the sample value ID.
  18. host1(config-mgmtevent-trigger)#delta-sampling
    
    
    
  1. (Optional) Configure the desired SNMP security level for the agent that you want to poll.
  2. host1(config)#snmp security read
    
    
    
  3. Define the test values that you want this trigger to use.

You can define a Boolean test, existence test, or threshold test. See the following sections for procedures.

Defining a Boolean Test

You can configure a Boolean trigger to test whether the value of an integer object is equal, unequal, greater than, less than, less than or equal to, or greater than or equal to some defined value.

To define a Boolean test:

  1. Define the Boolean-test comparison that you want this trigger to use.
  2. host1(config-mgmtevent-trigger)#boolean-test comparison greater
    
    
    
  3. (Optional) Specify that you do not want the Boolean test to perform a comparison when this trigger first becomes active.
  4. host1(config-mgmtevent-trigger)#boolean-test startup
    
    
    
  5. Specify the events that you want the Boolean-test trigger to use by entering an event owner name and event name.

    NOTE: You do not need to bind a failure event to a trigger. If you create a failure event and a failure occurs, the router sends the trap if the event owner is the same as the trigger owner.


  6. host1(config-mgmtevent-trigger)#boolean-test event george trigger1
    
    
    

When specifying an event, use the exact owner name and event name.Specify the Boolean value to which the test compares.

host1(config-mgmtevent-trigger)#boolean-test value 5175438

  1. Specify the agent on which the object resides.
  2. host1(config-mgmtevent-trigger)#agent context-name router1
    
    
    

You can obtain the agent context name for a virtual router from the show snmp agent command. The agent context name is independent of the virtual router name.Enable the trigger.

host1(config-mgmtevent-trigger)#enable

Once enabled, you cannot edit an event or trigger configuration. To change an enabled event or trigger, you must delete it and re-create it.

Defining an Existence Test

An existence test looks for the existence of a MIB object. The appearance, disappearance, or a change in value of the object can trigger the existence test.

To define an existence test:

  1. Define the existence test test-type value that you want this trigger to use.
  2. host1(config-mgmtevent-trigger)#existence-test test-type changed
    
    
    
  3. Define the startup threshold condition—absent or present—that you want this trigger to use.
  4. host1(config-mgmtevent-trigger)#existence-test startup absent
    
    
    
  5. Specify the events that you want the existence-test trigger to use by entering an event owner name and event name.

    NOTE: You do not need to bind a failure event to a trigger. If you create a failure event, if a failure occurs, and if the trigger owner and the event owner are the same, the router sends the trap.


  6. host1(config-mgmtevent-trigger)#boolean-test event george trigger1
    
    
    

When specifying an event, make sure to use the exact owner name and event name.

  1. Specify the agent on which the object resides.
  2. host1(config-mgmtevent-trigger)#agent context-name router1
    
    
    

You can obtain the agent context name for a virtual router from the show snmp agent command. The agent context name is independent of the virtual router name.

  1. Enable the trigger.
  2. host1(config-mgmtevent-trigger)#enable
    
    
    

Once enabled, you cannot edit an event or trigger configuration. To change an enabled event or trigger, you must delete it and re-create it.

Defining a Threshold Test

To define a threshold test:

  1. Define the threshold-test values that you want this trigger to use.

    NOTE: The rising value must always be larger than the falling value. Entering a lower rising value than a falling value will provide invalid results or errors.


  1. Define the startup threshold condition that you predict the sample to initially follow—falling, rising, risingorfalling. For example, if you are sampling a MIB value that you know will start from zero and rise, you would specify a rising startup condition.
  2. host1(config-mgmtevent-trigger)#threshold-test startup rising
    
    
    
  3. Specify the events (rising or falling) that you want the threshold-test trigger to use by entering an event owner name and event name.

    NOTE: You do not need to bind a failure event to a trigger. If you create a failure event, if a failure occurs, and if the trigger owner and the event owner are the same, the router sends the trap.


  4. host1(config-mgmtevent-trigger)#threshold-test event falling sysadmin 
    fallingtrigger
    
    host1(config-mgmtevent-trigger)#threshold-test event rising sysadmin 
    risingtrigger
    
    
    

When specifying an event, make sure to use the exact owner name and event name.

  1. Specify the agent on which the object resides.
  2. host1(config-mgmtevent-trigger)#agent context-name router1
    
    
    

You can obtain the agent context name for a virtual router from the show snmp agent command. The agent context name is independent of the virtual router name.

  1. Enable the trigger.
  2. host1(config-mgmtevent-trigger)#enable
    
    
    

Once enabled, you cannot edit an event or trigger configuration. To change an enabled event or trigger, you must delete it and re-create it.

agent context-name

boolean-test

delta-sampling

enable

event

existence-test

frequency

notification id

resource

sample

set

snmp-server management-event

snmp-server security

threshold-test

trigger

Monitoring Events

To view the status of the SNMP agent, use the following show snmp agent command. To view statistics associated with events, resources, and triggers, use the show snmp management-event command.

show snmp agent

show snmp management-event


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