Cisco 7962G Administration Guide - Page 165

Chapter 9 Troubleshooting and Maintenance Where to Go for More Troubleshooting Information A Conceal Ratio of zero indicates that the IP network is delivering frames and packets on time with no loss. Troubleshooting Tips When you observe significant and persistent changes to metrics, use Table 9-5 for general 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 • Network impairment from packet loss or high jitter. Seconds increase significantly Conceal Ratio is near or at zero, • Noise or distortion in the audio channel such as echo or but the voice quality is poor. 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. 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 OL-14625-01 Cisco Unified IP Phone 7962G and 7942G Administration Guide for Cisco Unified Communications Manager 6.1 9-17