Enterasys Networks 6000 - Manual (Page 162)

How Rising and Falling Thresholds Work 4-27
Alarm Configuration
When you delete an event, be sure you edit all alarms that were pointing to that event, and
assign a new valid event to those thresholds; note, too, that deleting an event automatically
deletes its associated actions, as actions cannot exist in the absence of an association with
an event.
Again, as a general rule, we recommend that you do not delete an alarm or event of which
you are not the owner.
Viewing an Advanced Alarm Event Log
To view the log of occurrences for any event, highlight the event for which you wish to
view the log, then click on the Event Log button at the bottom of the Advanced
Alarm/Event List window; the Event Log window will appear.
The top portion of the window contains the device information boxes, as well as the event
index number and the event description; the log itself includes the following fields:
Index This index number is not the event’s index, but a separate index that
uniquely identifies this occurrence of the event.
Time Indicates the date and time of each event occurrence.
Description Provides a detailed description of the alarm that triggered the event:
whether it was a rising or falling alarm, the alarm index number, the
alarm variable name and object identifier (OID), the alarmSampleType
(1=absolute value; 2=delta value), the value that triggered the alarm, the
configured threshold that was crossed, and the event description. Use
the scroll bar at the bottom of the log to view all the information
provided.
Each log will hold only a finite number of entries, which is determined by the resources
available on the device; when the log is full, the oldest entries will be replaced by new
ones.
How Rising and Falling Thresholds Work
Rising and falling thresholds are intended to be used in pairs, and can be used to provide
notification of spikes or drops in a monitored value — either of which can indicate a
network problem. To make the best use of this powerful feature, however, pairs of
thresholds should not be set too far apart, or the alarm notification process may be
defeated: a built-in hysteresis function designed to limit the generation of events specifies
that, once a configured threshold is met or crossed in one direction, no additional events
NOTE
In accordance with Year 2000 compliance requirements, NetSight Element Manager now
displays and allows you to set all dates with four-digit year values.