Defining RMON Alarms

RMON alarms provide a mechanism for setting thresholds and sampling intervals to generate exception events on any counter or any other SNMP object counter maintained by the agent. Both the rising and falling thresholds must be configured in the alarm. After a rising threshold is crossed, another rising event is not generated until the companion falling threshold is crossed. After a falling alarm is issued, the next alarm is issued when a rising threshold is crossed.

One or more alarms are bound to an event. The event indicates the action to be taken when the alarm occurs.

The Alarms page provides the ability to configure alarms and to bind them with events. Alarm counters can be monitored by either absolute values or changes (delta) in the counter values.

To enter RMON alarms:

  1. Click RMON > Alarms. The Alarms page opens.
  2. Click Add. The Add RMON Alarm page opens.
  3. Enter the parameters.
    • Alarm Entry--Displays the alarm entry number.
    • Interface--Select the type of interface for which RMON statistics are displayed.
    • Counter Name--Select the MIB variable that indicates the type of occurrence measured.
    • Counter Value--Displays the value of the statistic during the last sampling period.
    • Sample Type--Select the sampling method to generate an alarm. The options are:
      • Absolute--If the threshold is passed, an alarm is generated.
      • Delta--Subtracts the last sampled value from the current value. The difference in the values is compared to the threshold. If the threshold was passed, an alarm is generated.
    • Rising Threshold--Enter the rising counter value that triggers the rising threshold alarm.
    • Rising Event--Select an event, from those that you defined in the Events table, to be performed when a rising event is triggered. Events are created in the Events page.
    • Falling Threshold--Enter the falling counter value that triggers the falling threshold alarm.
    • Falling Event--Selects an event, from those defined in the Events table, to be performed when a falling event is triggered.
    • Startup Alarm--Select the first event from which to start generation of alarms. Rising is defined by crossing the threshold from a low-value threshold to a higher-value threshold.
      • Rising Alarm--A rising counter value triggers the rising threshold alarm.
      • Falling Alarm--A falling counter value triggers the falling threshold alarm.
      • Rising and Falling--Both a rising and falling counter values trigger the alarm.
    • Interval--Enter the alarm interval time in seconds.
    • Owner--Enter the name of the user or network management system that receives the alarm.
  4. Click Apply. The RMON alarm is added and the Running Configuration file is updated.