Cisco CP-7975G Administration Guide - Page 221

Chapter 9 Troubleshooting and Maintenance Where to Go for More Troubleshooting Information Table 9-5 Changes to Voice Quality Metrics Metric Change Condition MOS LQK scores decrease significantly Network impairment from packet loss or high jitter: • Average MOS LQK decreases could indicate widespread and uniform impairment. • Individual MOS LQK decreases indicate bursty impairment. Cross-check with Conceal Ratio and Conceal Seconds for evidence of packet loss and jitter. MOS LQK scores decrease significantly • Check to see if the phone is using a different codec than expected (RxType and TxType). • Check to see if the MOS LQK version changed after a firmware upgrade. Conceal Ratio and Conceal Seconds increase significantly • Network impairment from packet loss or high jitter. Conceal Ratio is near or at zero, • Noise or distortion in the audio channel such as echo or audio but the voice quality is poor. levels. • Tandem calls that undergo multiple encode/decode such as calls to a mobile network or calling card network. • Acoustic problems coming from a speakerphone, handsfree mobile phone or wireless headset. Check packet transmit (TxCnt) and packet receive (RxCnt) counters to verify that voice packets are flowing. 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_series_home.html • Cisco Products and Services (Technical Support and Documentation): http://www.cisco.com/en/US/products/sw/voicesw/tsd_products_support_ category_home.html OL-23092-01 Cisco Unified IP Phone Administration Guide for Cisco Unified Communications Manager 8.5 9-19