Alarms

RMON alarms provide a mechanism for setting thresholds and sampling intervals to generate exception events on counters 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, no rising events are 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, which indicates the action to be taken when the alarm occurs.

Alarm counters can be monitored by either absolute values or changes (delta) in the counter values.

To enter RMON alarms, complete the following steps:

Procedure

Step 1

Click Status and Statistics > RMON > Alarms.

All previously defined alarms are displayed. The fields are described in the Add RMON Alarm page below.

Step 2

Click Add.

Step 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.

Sample Type

Select the sampling method to generate an alarm. The options are:

  • Absolute—If the threshold is crossed, 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 crossed, an alarm is generated.

Rising Threshold

Enter the value that triggers the rising threshold alarm.

Rising Event

Select an event to be performed when a rising event is triggered.

Falling Threshold

Enter the value that triggers the falling threshold alarm.

Falling Event

Select an event 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 value triggers the rising threshold alarm.

  • Falling Alarm—A falling value triggers the falling threshold alarm.

  • Rising and Falling—Both rising and falling 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.
Step 4

Click Apply. The RMON alarm is saved to the Running Configuration file.