Troubleshooting Tips - Cisco 7911G - IP Phone VoIP Administration Manual

Chapter 9 Troubleshooting and Maintenance
Note

Troubleshooting Tips

Cisco Unified IP Phone 7906G and 7911G for Cisco Unified Communications Manager 6.0
OL11954-01
CVTQ does not support wideband (7 kHz) speech codecs, as ITU has not
•
defined the extension of the technique to wideband. Therefore, MOS 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/low packet loss, and lower scores (approximately 3.5) indicate low
quality/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.
When you observe significant and persistent changes to metrics, use
general troubleshooting information:
Monitoring the Voice Quality of Calls
Table 9-4 for
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