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Cisco Unified IP Phone 6921, 6941, and 6961 Administration Guide for Cisco Unified Communications Manager 7.1 (SCCP)
OL-19025-01
Chapter 9 Troubleshooting and Maintenance
Where to Go for More Troubleshooting Information
Note Concealment ratio and concealment seconds are primary measurements based on frame loss. A Conceal
Ratio of zero indicates that the IP network is delivering frames and packets on time with no loss.
You can access voice quality metrics from the Cisco Unified IP Phone by using the Call Statistics screen
(see the “Call Statistics Screen” section on page 7-8) or remotely by using Streaming Statistics (see the
Monitoring the Cisco Unified IP Phone Remotely chapter).
Troubleshooting Tips
When you observe significant and persistent changes to metrics, use Table 9-3 for general
troubleshooting information.
Note Voice quality metrics do not account for noise or distortion, only frame loss.
Where to Go for More Troubleshooting Information
If you have additional questions about troubleshooting the Cisco Unified IP Phones, several Cisco.com
web sites can provide you with more tips. Choose from the sites available for your access level.
• Cisco Unified IP Phone Troubleshooting Resources:
http://www.cisco.com/en/US/products/hw/phones/ps379/tsd_products_support_troubleshoot_and_
alerts.html
• Cisco Products and Services (Technical Support and Documentation):
http://www.cisco.com/en/US/products/ps10326/tsd_products_support_series_home.html
Ta ble 9-3 Changes to Voice Quality Metrics
Metric Change Condition
Conceal Ratio and Conceal
Seco
nds increase significantly
Network impairment from packet loss or high jitter.
Conceal Ratio is near or at zero,
bu
t the voice quality is poor.
• Noise or distortion in the audio channel such as echo or
audio levels.
• Tandem calls that undergo multiple encode/decode such as
calls to a cellular network or calling card network.
• Acoustic problems coming from a speakerphone,
handsfree cellular phone or wireless headset.
Check packet transmit (TxCnt) and packet receive (RxCnt)
counters to verify that
voice packets are flowing.