AudioCodes Mediant 4000 SBC User Manual page 773

CHAPTER 47 Viewing Performance Monitoring
When the threshold of a voice metric is crossed, the device changes the alarm severity and
corresponding color-coded quality state of the call:
■ Minor Threshold (Yellow): Lower threshold that indicates changes from Green or Red to
Yellow.
■ Major Threshold (Red): Higher threshold that indicates changes from Green or Yellow to
Red.
The device also uses hysteresis to determine whether the threshold has indeed being crossed.
Hysteresis defines the amount of fluctuation from the threshold in order for the threshold to be
considered as crossed (i.e., change in color state). Hysteresis is used to avoid false reports being
sent by the device. Hysteresis is used only for threshold crossings toward a lesser severity (i.e.,
from Red to Yellow, Red to Green, or Yellow to Green).
The following example is used to explain how the device considers threshold crossings. The
example is based on the ASR of a call, where the Major threshold is configured to 70%, the Minor
threshold to 90% and the hysteresis for both thresholds to 2%:
Table 47-1: Threshold Crossings based on Threshold and Hysteresis
Threshold
Crossing
Green to
Yellow (Minor
alarm)
Green to Red
(Major alarm)
Yellow to Red
(Major alarm)
Red to Yellow
(Minor alarm)
Red to Green
(alarm
cleared)
Yellow to
Green (alarm
cleared)
Calculation
The change occurs if the measured metric crosses the
configured Minor threshold only (i.e., hysteresis is not
used).
The change occurs if the measured metric crosses the
configured Major threshold only (i.e., hysteresis is not
used).
The change occurs if the measured metric crosses the
configured Major threshold only (i.e., hysteresis is not
used).
The change occurs if the measured metric crosses the
configured Major threshold with hysteresis.
The change occurs if the measured metric crosses the
configured Minor threshold with hysteresis.
The change occurs if the measured metric crosses the
configured Minor threshold with hysteresis.
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Mediant 4000 SBC | User's Manual
Threshold
based on
Example
90%
70%
70%
72% (i.e., 70 +
2)
92 (i.e., 90 + 2)
92 (i.e., 90 + 2)