3Com 3C16630A User Manual page 110

E-8 A E: RMON A M
PPENDIX AND DVANCED ANAGEMENT
The diagram below shows the variation of a typical counter with time.
Figure E-1 Counter Values During Autosetting Of Thresholds
Alarm thresholds may be autocalibrated or set manually.
Autocalibration is a means of calculating alarm thresholds specific to
the activity of the counter being monitored. For autocalibration, the
high threshold is set to 5% above the high tide mark. Also, the low
threshold is set to 20% below the high tide mark (see diagram above).
Manually, you may choose any value for the thresholds using your
network manager.
The tide marks are monitored continually during normal running to
provide data for later calibration. This explains the high tide mark being
above the threshold level in the diagram below.
DUA1663-0BAA03