Table of Contents
Advertisement
Chapter 9
Troubleshooting and Maintenance
Troubleshooting Tips
When you observe significant and persistent changes to metrics, use
troubleshooting information:
Table 9-5
Metric Change
MOS LQK scores decrease
significantly
MOS LQK scores decrease
significantly
Conceal Ratio and Conceal
Seconds increase significantly
Conceal Ratio is near or at zero,
but the voice quality is poor.
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.
•
•
OL-23091-01
Changes to Voice Quality Metrics
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
Cisco Unified IP Phone Administration Guide for Cisco Unified Communications Manager 8.6 (SCCP and SIP)
Condition
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.
•
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.
•
Network impairment from packet loss or high jitter.
•
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.
Where to Go for More Troubleshooting Information
Table 9-5
for general
9-17
Advertisement
Table of Contents
Troubleshooting
