User Guide

16
RMON 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:
1. Click
System Status > RMON > Alarms
. All previously-defined alarms are displayed. The
fields are described in the Add RMON Alarm page below.
•
Counter Value—Displays the value of the statistic during the last sampling period.
2. Click Add.
3. Enter the parameters.
•
Alarm Entry Index—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:
o
Absolute—If the threshold is crossed, an alarm is generated.
o
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.
o
Interval—Enter the alarm interval time in seconds.
•
Rising Event—Select an event to be performed when a rising event is triggered.
Events are created in the Events page.
•
Rising Threshold—Enter the value that triggers the rising threshold alarm
•
Falling Event—Select an event to be performed when a falling event is triggered.