Voice Quality Reporting - Cisco IP Phone 6851 Administration Manual

Metric Change
Conceal Ratio is near or at zero, but
the voice quality is poor.
MOS LQK scores decrease
significantly
MOS LQK scores increase
significantly
Voice quality metrics do not account for noise or distortion, only frame loss.
Note

Voice Quality Reporting

You can capture voice quality metrics for Voice over Internet Protocol (VoIP) sessions with a Session Initiation
Protocol (SIP) event package. Voice call quality information derived from RTP and call information from
SIP is conveyed from a User Agent (UA) in a session (reporter) to a third party (collector).
The Cisco IP phone uses User Datagram Protocol (UDP) to send a SIP PUBLISH message to a collector
server.
Supported Scenarios for Voice Quality Reporting
Currently, only the basic call scenario supports voice quality reporting. A basic call can be a peer to peer
incoming or outgoing call. The phone sends the SIP Publish message when a call ends.
Condition
• 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.
Network impairment from packet loss or high jitter levels:
• Average MOS LQK decreases may indicate widespread and
uniform impairment.
• Individual MOS LQK decreases may indicate bursty impairment.
Cross-check the 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.
Cisco IP Phone 6800 Series Multiplatform Phones Administration Guide
Voice Quality Reporting
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