Triple-Play Service Deployment

Chapter 8: Troubleshooting VoIP
Ultimately, as with video, VoIP service quality is determined
subjectively by the end user. Yet, a service provider can make
objective measurements to judge the performance and quality of
experience (QoE) the network will deliver. A model for mapping
objectively measurable metrics to important QoE metrics is the basis
for good installation and troubleshooting procedures, which in turn
play an important role in an overall service assurance program.
Figure 8.3 outlines the way in which objective metrics can be
mapped to subjective QoE issues by organizing the issues into
four parts.
VoIP Quality
Content Quality
Voice Stream Quality
Transport Quality
Transaction Quality
Figure 8.3 QoS and QoE mapping for VoIP services
VoIP QoS QoE
Parameters
MOS
Echo level and delay
Static quality voice during
Source Artifacts, note 1
playback; near and far end
echo apparent
Codec provisioning
Live playback
Packetization rate
Continuity Error
RTCP availability
Pops, clicks, loss of speech
Jitter buffer size
Dropped calls
PCR Jitter
PSI Table Data (Error)
Echo cancellor depth
IP Packet Loss
IP Packet Jitter
IP Packet Delay
IP Packet OOS
Non-registering phones
Service Provisioning
incomplete in-bound/
out-bound calls
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