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 supports periodic SIP publish message.
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 some of the codecs
and MOS scores. The phone supports all codecs. For all codecs, the phone sends the SIP Publish message.
Minimum Call Duration for
Valid MOS Value
MOSComplexity and DescriptionCodec
10 secondsA minimum value of 4.1 indicates good
voice quality.
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.
G.711
(A-law
and
u-law)
30 secondsA minimum value of 3.5 indicates good
voice quality.
Low to medium complexity.G.729A
30 secondsA minimum value of 3.5 indicates good
voice quality.
Contains the same reduced
complexity modifications
present in the G.729A.
G.729AB
Configure Voice Quality Reporting
You can generate a voice quality report for each extension on the phone. The parameters for the Voice Quality
Metrics (VQM) SIP Publish Message help you to:
• Generate voice quality reports.
• Name your reports.
• Determine when your phone sends SIP Publish messages.
Cisco IP Phone 8800 Series Multiplatform Phone Administration Guide for Release 11.3(1) and Later
281
Cisco IP Phone Configuration
Voice Quality Reporting
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