EX2500 Ethernet Switch Configuration Guide
68 RMON Group 3—Alarms
3. View RMON history for the port.
ex2500(config)# show rmon history
RMON is enabled
Index IFOID Interval Rbnum Gbnum
------ ---------- -------- ----- -----
1 ifEntry.1.7 120 30 30
History Ether table is empty
RMON Group 3—Alarms
The RMON Alarm Group allows you to define a set of thresholds to determine
network performance. When a configured threshold is crossed, an alarm is
generated. For example, you can configure the switch to issue an alarm if more
than 1,000 CRC errors occur during a 10-minute time interval.
Each Alarm index consists of a variable to monitor, a sampling time interval, and
parameters for rising and falling thresholds. The Alarm Group can be used to track
rising or falling values for a MIB object. The object must be a counter, gauge,
integer, or time interval.
Use one of the following commands to correlate an Alarm index to an Event index:
ex2500(config)# rmon alarm <alarm number> rise-event <event number>
ex2500(config)# rmon alarm <alarm number> fall-event <event number>
When the alarm threshold is reached, the corresponding event is triggered.
Alarm MIB Objects
The most common data types used for alarm monitoring are ifStats: errors, drops,
invalid CRCs, and so on. These MIB Object Identifiers (OIDs) correlate to the ones
tracked by the History Group. An example of an ICMP statistic is as follows:
1.3.6.1.2.1.5.1.0 – mgmt.icmp.icmpInMsgs
This value represents the alarm’s MIB OID, as a string. Note that for non-tables, you
must supply a
.0 to specify end node.
Configuring RMON Alarms
Configure the RMON Alarm parameters to track ICMP messages.
ex2500(config)# rmon alarm 1 oid 1.3.6.1.2.1.5.8.0 alarm-type rising rise-event 110
ex2500(config)# rmon alarm 1 interval-time 60
ex2500(config)# rmon alarm 1 rising-threshold 200
ex2500(config)# rmon alarm 1 sample-type delta
ex2500(config)# rmon alarm 1 owner "Alarm for icmpInEchos"
This configuration creates an RMON alarm that checks icmpInEchos on the switch
once every minute. If the statistic exceeds 200 within a 60-econd interval, an alarm
is generated that triggers event index 110.
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