Setting Alarm Thresholds - 3Com CoreBuilder 2500 User Manual

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Occasionally, counters can produce misleading results. Because counters
are finite, they are useful for comparing rates. When counters reach a
predetermined limit, they roll over (that is, return to 0). A single low
counter value may accurately represent a condition on the network. On
the other hand, the same value may simply indicate a rollover.
When you disable a port, the application may not update some of its
associated statistics counters.
An alarm calculates the difference in counter values over a set time
interval and remembers the high and low values. When the value of a
counter exceeds a preset threshold, the alarm reports this occurrence.
Using Transcend Enterprise Manager or any other SNMP network
management application, you can assign alarms to monitor any counter,
gauge, timetick, or integer. See the documentation for your management
application for details about setting up alarms.

Setting Alarm Thresholds

Thresholds determine when an alarm reports that a counter has exceeded
a certain value. You can set alarm thresholds manually through the
network, choosing any value for them that is appropriate for your
application. The network management software monitors the counters
and thresholds continually during normal operations to provide data for
later calibration.