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Cisco Unified IP Conference Station 7937G Administration Guide for Cisco Unified Communications Manager 6.0
OL-11560-01 Rev. B0
Chapter 9 Troubleshooting and Maintenance
Using the Quality Report Tool
Using the Quality Report Tool
The Quality Report Tool (QRT) is a voice quality and general problem-reporting tool for the conference
station. The QRT feature is installed as part of Cisco Unified Communications Manager.
You can configure users’ conference stations with QRT. When you do so, users can report problems with
conference station calls by pressing the
QRT
softkey. This softkey is available only when the conference
station is in the Connected, Connected Conference, Connected Transfer, and/or OnHook states.
When a user presses the
QRT
softkey, a list of problem categories appears. The user selects the
appropriate problem category and this feedback is logged in an XML file. Actual information logged
depends on the user selection and whether the destination device is a conference station.
For more information about using QRT, refer to
Cisco Unified Communications Manager Features and
Services Guide
.
Monitoring the Voice Quality of Calls
To measure the voice quality of calls that are sent and received within the network, conference stations
use these statistical metrics that are based on concealment events. The DSP plays concealment frames
to mask frame loss in the voice packet stream.
•
Concealment Ratio metrics—Show the ratio of concealment frames over total speech frames. An
interval conceal ratio is calculated every 3 seconds.
•
Concealed Second metrics—Show the number of seconds in which the DSP plays concealment
frames due to lost frames. A severely “concealed second” is a second in which the DSP plays more
than five percent concealment frames.
•
MOS-LQK metrics—Use a numeric score to estimate the relative voice listening quality. The
conference station calculates the mean opinion score (MOS) for listening quality (LQK) based
audible concealment events due to frame loss in the preceding 8 seconds, and includes perceptual
weighting factors such as codec type and frame size.
MOS LQK scores are produced by a Cisco proprietary algorithm that is an implementation of
P.VTQ, an ITU provisional standard.
Note
Concealment ratio and concealment seconds are primary measurements based on frame loss while
MOS LQK scores project a “human-weighted” version of the same information on a scale from
5 (excellent) to 1 (bad) for measuring listening quality.
Listening quality scores (MOS LQK) relate to the clarity or sound of the received voice signal.
Conversational quality scores (MOS CQ such as G.107) include impairment factors, such as delay, that
degrade the natural flow of conversation.
For information about configuring voice quality metrics for conference stations, refer to
Cisco Unified
Communications Manager System Guide,
“Cisco Unified IP Phones” chapter, “Phone Features” section.
You can access voice quality metrics from the conference station by using the Call Statistics screen
(see the
“Call Statistics Screen” section on page 7-4
) or remotely by using Streaming Statistics
(see
Chapter 8, “Monitoring the Conference Station Remotely”
).
To use the metrics for monitoring voice quality, note the typical scores under normal conditions of zero
packet loss, and use the metrics as a baseline for comparison.
