Rmon Alarm - D-Link D-View 5.1 User Manual

D-View 5.1 User's Guide

RMON Alarm

Alarm Group
The Alarm Group periodically takes statistical samples from variables in the probe and
compares them to previously configured thresholds. If the monitored variable crosses a
threshold, an event is generated. A hysteresis mechanism is implemented to limit the
generation of alarms. This group consists of the alarmTable and requires the
implementation of the event group.
The Alarm Table consists of a list of Alarm entries that are made up of parameters that
are set up to periodically check for alarm conditions. To use the Alarm Group, a new
data entry must be added to define threshold parameters:
1. Click Add to display the Alarm Table Add box.
2. Descriptions of the fields are as follows:
♦ Index – This value is randomly generated upon opening the Add box. The value
uniquely identifies this entry. Other than numerical position in the Alarm Table,
there is no benefit or disadvantage in choosing a specific index value.
♦ Interval – The interval in seconds over which the data is sampled and
compared with the rising and falling thresholds. When setting this variable, care
should be taken in the case of deltaValue sampling – the interval should be set
short enough that the sampled variable is very unlikely to increase or decrease
by more than 2^31 + 1 during a single sampling interval.
♦ Sampling – The method of sampling the selected variable and calculating the
value to be compared against the thresholds. If the value of this object is
absoluteValue(1), the value of the selected variable will be compared directly
with the thresholds at the end of the sampling interval. If the value of this object
is deltaValue(2), the value of the selected variable at the last sample will be
subtracted from the current value, and the difference compared with the
thresholds.
♦ Variable – The object identifier of the particular variable to be sampled. Only
variables that resolve to an ASN.1 primitive type of INTEGER (INTEGER,
Counter, Gauge, or TimeTicks) may be sampled.
♦ Threshold Value – These are threshold values for the sampled statistic.
♦ Rising – When the current sampled value is greater than or equal to this
threshold, and the value at the last sampling interval was less than this
threshold, a single event will be generated. A single event will also be generated
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