Cisco Systems SG50028PK9NA Defining RMON Alarms

Status and Statistics
Managing RMON
26 Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version)
2
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, 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.
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:
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. In
addition to those fields, the following field appears:
•Counter Value—Displays the value of the statistic during the last sampling
period.
STEP 2 Click Add.
STEP 3 Enter the pa rameters.
•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.