Despite the features that make Voice over IP so
attractive from the standpoint of cost and flexibility of
telephone services, businesses will only adopt it once
they've determined whether, and under what circumstances,
the quality of VoIP will be satisfactory to users.
This hands-on guide supplies you with all the tools you
need for VoIP
service quality analysis, including explicit
directions for:
- designing subjective tests and interpreting
results
- selecting, extending, and applying speech distortion
and multiple effects models
- examining call set-up times for IP telephony
- determining requirements for multimedia exchanges.
Without jargon, or tech talk, Hardy delivers solid
information on means of measuring, assessing, and improving
VoIP quality. He gives you expert information and hands-on
specifics, showing you:
- The factors that can create a negative caller
experience and how packet switching affects them
- What to look for in assessing VoIP quality
- How to elicit and interpret user evaluations of voice
quality
- How to estimate likely user perception of voice quality
by objective test and analysis
- When and how to apply alternative quality measurement
techniques to overcome quality shortfalls.
Contents
Part 1: FOUNDATIONS
- Basics
- Principal System-Level Determinants of Connection
Quality
- Quality Expectations and Requirements
- Impairments Created or Exacerbated by Packet
Switching
Part 2: MEASUREMENT AND EVALUATION OF VOICE QUALITY
- Voice Quality
- Service Attribute Tests
- Measurement of Speech Distortion
- Multiple-Effects Models
- Applications
Part 3: OTHER ASPECTS OF QUALITY OF SERVICE
- Other Quality of Service Concerns
- Quality of Voice for Interactive Multimedia
Exchange
Afterword
Appendix A: Types of Codecs
Appendix B: How a Jitter Buffer Works
Appendix C: Extensions of the Loss/Noise Grade of Service
Model
Appendix D: U.S. Patents for Voice Quality Measurement and
Analysis Technology