Cisco 6800 Series Administration Manual page 337

Phone Troubleshooting
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.
Mean Opinion Scores and Codecs
The voice quality metrics use Mean Opinion Score (MOS) to rate the quality. A MOS rating of 1 is the lowest
quality; a MOS rating of 5 is the highest quality. The following table gives a description of the codecs and
MOS scores. For other codecs, the phone does not send the SIP Publish message.
Codec
G.711
(A-law
and
u-law)
G.729A
G.729AB
Configure Voice Quality Reporting
You can enable voice quality reporting on the phone with the web interface. Each extension on a phone has
a separate voice quality report. For each extension on the phone, use the corresponding Voice Quality Report
Address field to configure the generation of voice quality report.
Complexity and Description
Very low complexity.
Supports uncompressed 64
kbps digitized voice
transmission at one to ten 5
ms voice frames-per-packet.
This codec provides the
highest voice quality and
uses the most bandwidth of
any of the available codecs.
Low to medium complexity.
Contains the same reduced
complexity modifications
present in the G.729A.
Cisco IP Phone 6800 Series Multiplatform Phones Administration Guide
MOS
A minimum value of 4.1 indicates good
voice quality.
A minimum value of 3.5 indicates good
voice quality.
A minimum value of 3.5 indicates good
voice quality.
Voice Quality Reporting
Minimum Call Duration for
Valid MOS Value
10 seconds
30 seconds
30 seconds
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