[...]... experience when voice exchanges are packet-switched Part 2, Measurement and Evaluation of Voice Quality, turns to the central question of ways and means of gauging likely user perception of the quality of packet-switched voice services with respect to the audible quality of voice and naturalness of the exchanges It describes commonly used techniques for measuring and analyzing voice quality, together... exchanges of voice signals The possibility of creating such interactive packet-switched voice services creates both opportunities and a problem for development The development of viable packet-switched voice transport creates opportunities both for merging the transport of voice and data services, thereby realizing substantial operational flexibility and economies in switching voice service, and for development... their application to packet-switched voice services The presentation is divided into three parts: Part 1, Foundations, contains all of the background material needed for understanding the factors that affect users’ perception of, and satisfaction with, quality of packet-switched voice services It covers the basic notions of quality of service derived from analysis of user concerns with quality, together... performance of the packet-switched transport are needed to ensure that the voice quality will be acceptable to users Part 3, Other Aspects of Quality of Service, concludes this book with brief descriptions of the ways and means of measuring and gauging likely user perception of packet-switched voice services with respect to the other user concerns with telecommunications QoS described in Ref 1 and some of... operational characteristics of packet-switched voice services relative to the needs of their application and determine how users are likely to perceive the quality of those services At the same time, telecommunications service providers must be able to configure and operate packet-switched networks in a way that assures requirements for user perception of quality of service (QoS) are met The material... 1 and some of the unique quality requirements associated with some kinds of packet-switched voice services VoIP SERVICE QUALITY This page intentionally left blank PART 1 Foundations Copyright 2003 by The McGraw-Hill Companies, Inc Click Here for Terms of Use T he object of study of this book is perceived quality of packetswitched voice services The purpose is to describe and suggest applications... packet-switched voice systems Accordingly, we begin here with a presentation of fundamentals, covering such basics as notions of voice services, measurement and evaluation of quality of voice service, and differences in implementation and performance between packet- and circuit-switched voice services Although these topics may look familiar to the knowledgeable reader, it is important for everyone to become familiar... the demand and the amount of bandwidth allocated to that traffic 3 Perceived quality of service Perceived quality of service is distinguished from intrinsic QoS as being what results when the service is actually used Perceived QoS is, then, determined by what users experience as the effects of intrinsic QoS on their communications activities, in their environment, in handling their demand, and how... transport protocol and voice codec (e.g., VoIP using a G.729 codec) is by itself an inadequate characterization of a packet-switched voice service for purposes of measuring and reporting characteristics that are likely to affect user perception of the quality of that service Rather, any system description must as a minimum also specify: 1 Whether silence suppression is activated and the characteristics... satisfactory quality on similar services and are usually expressed as doubts or questions seeking positive reassurance For the case of packet-switched voice, users’ principal concerns are with the connection quality, i.e., the quality of conversations carried over the service, as typified by concerns with the quality of what is heard: Will connections exhibit impairments that will make it difficult to hear and . as notions of voice services, measurement and evaluation of quali- ty of voice service, and differences in implementation and performance between packet- and circuit-switched voice services. Although. Customer Wants a Service- Level Agreement for Voice Quality 197 Part 3 OTHER ASPECTS OF QUALITY OF SERVICE 203 Chapter 10 Other Quality of Service Concerns 205 The Quality of Service (QoS) Model. packet-switched voice services with respect to the audible quality of voice and naturalness of the exchanges. It describes commonly used techniques for measuring and analyzing voice quality, together