It is also important to distinguish significant changes from random changes in metrics. Significant changes
are scores that change about 0.2 MOS or more and persist in calls that last longer than 30 seconds. Conceal
ratio changes indicate a frame loss greater than 3 percent.
The MOS LQK scores can vary based on the codec that the Cisco Unified IP Phone uses. The following
codecs provide these corresponding maximum MOS LQK scores under normal conditions with zero frame
loss for Cisco Unified Phone 8941 and 8945:
•
G.711: 4.5 MOS LQK
•
G.722: 4.5 MOS LQK
•
G.728/iLBC: 3.9 MOS LQK
•
G729A/AB: 3.7 MOS LQK
Note
•
Cisco Voice Transmission Quality (CVTQ) does not support wideband (7 kHz) speech codecs,
because ITU has not defined the extension of the technique to wideband. Therefore, MOS LQK
scores that correspond to G.711 performance are reported for G.722 calls to allow basic quality
monitoring, rather than not reporting an MOS score.
•
Reporting G.711-scale MOS scores for wideband calls through the use of CVTQ allows basic-quality
classifications to be indicated as good/normal or bad/abnormal. Calls with high scores (approximately
4.5) indicate high quality or a low packet loss, and lower scores (approximately 3.5) indicate low
quality or a high packet loss.
•
Unlike MOS, the conceal ratio and concealed seconds metrics remain valid and useful for both
wideband and narrowband calls.
A conceal ratio of zero indicates that the IP network is delivering frames and packets on time with no loss.
Video Metrics
The phones do not support video metrics. This means that you can't see the following information about the
video portion of a call:
•
videoContentType
•
videoDuration
•
numberVideoPacketsSent
•
numberVideoOctetsSent
•
numberVideoPacketsReceived
•
numberVideoOctetsReceived
•
numberVideoPacketsLost
•
videoAverageJitter
Cisco Unified IP Phone 8941 and 8945 Administration Guide for Cisco Unified Communications Manager 10.0 (SCCP
and SIP)
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Video Metrics