AudioCodes Mediant 500L - Page 890

User's Manual 890 Document #: LTRT-10532
Mediant 500L Gateway & E-SBC
At any given time during a call, a voice metric can be in one of the following color-coded
quality states (as displayed by OVOC):
 Green: Indicates good call quality
 Yellow: Indicates fair call quality
 Red: Indicates poor call quality
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%:
Figure 55-4: Example of Threshold Crossings (ASR)
Table 55-2: Threshold Crossings based on Threshold and Hysteresis
Threshold Crossing Calculation
Threshold based on
Example
Green to Yellow (Minor alarm) The change occurs if the measured metric
crosses the configured Minor threshold only
(i.e., hysteresis is not used).
90%
Green to Red (Major alarm) The change occurs if the measured metric
crosses the configured Major threshold onl
y
(i.e., hysteresis is not used).
70%
Yellow to Red (Major alarm) The change occurs if the measured metric
crosses the configured Major threshold only
(i.e., hysteresis is not used).
70%
Red to Yellow (Minor alarm) The change occurs if the measured metric
crosses the configured Major threshold with
hysteresis.
72% (i.e., 70 + 2)
Red to Green (alarm cleared) The change occurs if the measured metric
crosses the configured Minor threshold with
92 (i.e., 90 + 2)