VOIP TECHNOLOGIES Edited by Shigeru Kashihara VoIP Technologies Edited by Shigeru Kashihara Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2011 InTech All chapters are Open Access articles distributed under the Creative Commons Non Commercial Share Alike Attribution 3.0 license, which permits to copy, distribute, transmit, and adapt the work in any medium, so long as the original work is properly cited. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published articles. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Jelena Marusic Technical Editor Teodora Smiljanic Cover Designer Martina Sirotic Image Copyright WitR, 2010. Used under license from Shutterstock.com First published February, 2011 Printed in India A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechweb.org VoIP Technologies, Edited by Shigeru Kashihara p. cm. ISBN 978-953-307-549-5 free online editions of InTech Books and Journals can be found at www.intechopen.com Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Preface IX VoIP Quality Assessment Technologies 1 Mousa AL-Akhras and Iman AL Momani Assessment of Speech Quality in VoIP 27 Zdenek Becvar, Lukas Novak and Michal Vondra Enhanced VoIP by Signal Reconstruction and Voice Quality Assessment 45 Filipe Neves, Salviano Soares, Pedro Assunção and Filipe Tavares An Introduction to VoIP: End-to-End Elements and QoS Parameters 79 H. Toral-Cruz, J. Argaez-Xool, L. Estrada-Vargas and D. Torres-Roman Influences of Classical and Hybrid Queuing Mechanisms on VoIP’s QoS Properties 95 Sasa Klampfer, Amor Chowdhury, Joze Mohorko and Zarko Cucej VoIP System for Enterprise Network 127 Moo Wan Kim and Fumikazu Iseki An Opencores /Opensource Based Embedded System-on-Chip Platform for Voice over Internet 145 Sabrina Titri, Nouma Izeboudjen, Fatiha Louiz, Mohamed Bakiri, Faroudja Abid, Dalila Lazib and Leila Sahli Experimental Characterization of VoIP Traffic over IEEE 802.11 Wireless LANs 173 Paolo Dini, Marc Portolés-Comeras, Jaume Nin-Guerrero and Josep Mangues-Bafalluy VoIP Over WLAN: What About the Presence of Radio Interference? 197 Leopoldo Angrisani, Aniello Napolitano and Alessandro Sona Contents Contents VI VoIP Features Oriented Uplink Scheduling Scheme in Wireless Networks 219 Sung-Min Oh and Jae-Hyun Kim Scheduling and Capacity of VoIP Services in Wireless OFDMA Systems 237 Jaewoo So Reliable Session Initiation Protocol 253 Harold Zheng, and Sherry Wang Multi-path Transmission, Selection and Handover Mechanism for High-Quality VoIP 277 Jingyu Wang, Jianxin Liao and Xiaomin Zhu End-to-End Handover Management for VoIP Communications in Ubiquitous Wireless Networks 295 Shigeru Kashihara, Muhammad Niswar, Yuzo Taenaka, Kazuya Tsukamoto, Suguru Yamaguchi and Yuji Oie Developing New Approaches for Intrusion Detection in Converged Networks 321 Juan C. Pelaez Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Pref ac e Voice over IP (VoIP) is undoubtedly a powerful and innovative communication tool. Compared with the public switched telephone network (PSTN), VoIP off ers the benefi t of reducing communication and infrastructure cost. This makes it possible for every- one to easily keep in touch with family, friends, and clients around the world. Fur- thermore, VoIP has the potential to create new and a ractive communication tools by integrating with various applications, such as Web systems, presentation so ware, and photo viewers. In the near future, we expect VoIP to provide a rich multimedia com- munication service. However, voice communication over the Internet is inherently less reliable than PSTN. Since the Internet essentially works as a best-eff ort network without a Quality of Ser- vice (QoS) guarantee, and since voice data cannot be retransmi ed, voice quality may suff er from packet loss, delay, and ji er due to interference from other data packets. In wireless networks, such problems may be compounded by various characteristics of wireless media, including reduction of signal strength and radio interference. Addi- tionally, we need to pay closer a ention to security issues related to VoIP communica- tions. Thus, VoIP technologies are challenging research issues. This book comprises 15 chapters and encompasses a wide range of VoIP research, from VoIP quality assessment to security issues. Much of the content is focused on the key areas of VoIP performance investigation and enhancement. Each chapter includes vari- ous approaches that illustrate how VoIP aspires to be a powerful and reliable commu- nication tool. We hope that you will enjoy reading these diverse studies, and will fi nd a lot of useful information about VoIP technologies. Finally, I would like to thank all authors of the chapters for their great contributions. Shigeru Kashihara Nara Institute of Science and Technology Japan [...]... listening quality score (Ylq) and listening effort VoIP Quality Assessment Technologies VoIP Quality Assessment Technologies 11 11 Fig 3 Transformation from Hertz scale to Bark scale score (Yle) Both scores are in the range 1 to 5 and MOS score can be estimated using a linear combination of both scores (Duysburgh et al., 20 01; Zurek et al., 2002) 4 .1. 5 Perceptual speech quality measure (PSQM) PSQM originally... for cost reduction in phone calls VoIP also has other advantages, including: number portability, lower equipment cost, lower bandwidth requirements, lower operating and management expenses, widespread availability of IP, and other advantages (Collins, 2003; Heiman, 19 98; Low, 19 96; Moon et al., 2000; Rosenberg et al., 2 2 VoIP Technologies VoIP Technologies 19 99) VoIP can be used in many applications,... to detect 9 9 VoIP Quality Assessment Technologies VoIP Quality Assessment Technologies temporal variations As time-domain measures, SNR and SegSNR can be used for evaluation of non-speech signals (Quackenbush et al., 19 88; Mahdi and Picoviciv, 2009) SNR is defined as the ratio of a signal power to the noise power corrupting the signal: SNR = 10 log10 ∑n x2 (n) , ∑n ( x (n) − d(n))2 (1) where x(n) represents... Later it was standardised by ITU-T as Recommendation P.862 (ITU-T, 20 01; Rix et al., 20 01) Upon its standardisation, PSQM in Recommendation P.8 61 was withdrawn by ITU-T (ITU-T, 20 01; 2005b; Rohani & Zepernick, 2005; Zurek et al., 2002) 12 12 VoIP Technologies VoIP Technologies Real systems may include filtering and variable delay, as well as distortions due to channel errors and LBR codes PSQM was designed... The E-model which is one of the most widely used parametric-based methods defined according to ITU-T Recommendation G .10 7 (ITU-T, 2009) The details of the ITU-T Recommendation P.563 or 3SQM and the E-Model are discussed in the next sections 14 14 VoIP Technologies VoIP Technologies 4.2 .1 ITU-T recommendation P.563 or 3SQM In 2004 ITU-T standardised its P.563 Recommendation (ITU-T, 2004) for single-ended... which hinders its applicability for new networking conditions VoIP Quality Assessment Technologies VoIP Quality Assessment Technologies 5 5 Fig 1 Overview of VoIP measurement methods (Sun, 2004) Based on the above requirements and from the previous discussion, the subjective and intrusive solutions that will be discussed in sections 3 and 4 .1 respectively cannot be used for such task as they are manual... Signal Time-Alignment Perceptual Model Internal Representation of Degraded Signal Fig 4 Conceptual diagram of PESQ philosophy (ITU-T, 20 01) Quality Cognitive Model VoIP Quality Assessment Technologies VoIP Quality Assessment Technologies 13 13 4 .1. 7 Other methods Many other intrusive objective methods have been proposed by other researchers Fu et al proposed using an ANN model where the feature vector of... distance of 14 0-200 mm from the speakers mouth Also, the sound pressure level should be measured from a vertical position above the subjects seat while the furniture in place (ITU-T, 19 96b) Recommendation P.800 also specifies other conditions regarding the subjects who participate in the test such as they have not been directly involved in work connected with assessment of 6 6 VoIP Technologies VoIP Technologies. .. interval This difference is then normalised out of one signal to provide one or more measurements MNB algorithm starts by estimating the delay between the input speech signal and the output 10 10 VoIP Technologies VoIP Technologies speech signal due to the device or system (possibly IP network) under test This is done using cross-correlation of speech envelops because LBR codecs do not preserve the speech... The key parameters and the assigned distortion class are used for the adjustment of the speech Fig 5 Basic block diagram of P.563 overall structure (ITU-T, 2004) VoIP Quality Assessment Technologies VoIP Quality Assessment Technologies 15 15 Fig 6 Block diagram of P.563 algorithm detailing the various distortion classes used (ITU-T, 2004) quality model This provides a perceptual based weighting where . Intrusion Detection in Converged Networks 3 21 Juan C. Pelaez Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Pref ac e Voice over IP (VoIP) is undoubtedly a powerful and innovative. VOIP TECHNOLOGIES Edited by Shigeru Kashihara VoIP Technologies Edited by Shigeru Kashihara Published by InTech Janeza Trdine 9, 510 00 Rijeka, Croatia Copyright © 2 011 InTech All. availability of IP, and other advantages (Collins, 2003; Heiman, 19 98; Low, 19 96; Moon et al., 2000; Rosenberg et al., 1 2 VoIP Technologies 19 99). VoIP can be used in many applications, including: call