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Chapter 3
Device Management
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Figure 30: RMON History Controls Form
1. Index Box 2. Port Box 3. Requested Buckets Box 4. Granted Buckets Box 5. Interval Box 6. Owner Box 7. Apply Button
8. Delete Button 9. Reload Button
3.
Click Delete.
Section 3.9.2
Managing RMON Alarms
When Remote Monitoring (RMON) alarms are configured, RUGGEDCOM ROS examines the state of a specific
statistical variable.
Remote Monitoring (RMON) alarms define upper and lower thresholds for legal values of specific statistical
variables in a given interval. This allows RUGGEDCOM ROS to detect events as they occur more quickly than a
specified maximum rate or less quckly than a minimum rate.
When the rate of change for a statistics value exceeds its limits, an internal INFO alarm is always generated. For
information about viewing alarms, refer to
Additionally, a statistic threshold crossing can result in further activity. An RMON alarm can be configured to point
to a particular RMON event, which can generate an SNMP trap, an entry in the event log, or both. The RMON event
can also direct alarms towards different users defined for SNMP.
The alarm can point to a different event for each of the thresholds. Therefore, combinations such as trap on rising
threshold or trap on rising threshold, log and trap on falling threshold are possible.
Each RMON alarm may be configured such that its first instance occurs only for rising, falling, or all thresholds that
exceed their limits.
The ability to configure upper and lower thresholds on the value of a measured statistic provides for the ability to
add hysteresis to the alarm generation process.
If the value of the measured statistic over time is compared to a single threshold, alarms will be generated each
time the statistic crosses the threshold. If the statistic's value fluctuates around the threshold, an alarm can be
generated every measurement period. Programming different upper and lower thresholds eliminates spurious
alarms. The statistic value must travel between the thresholds before alarms can be generated. The following
illustrates the very different patterns of alarm generation resulting from a statistic sample and the same sample
with hysteresis applied.
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Section 4.6.2, "Viewing and Clearing Latched Alarms"
RUGGEDCOM ROS
User Guide
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Managing RMON Alarms
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