DATA COMMUNICATION PRINCIPLES For Fixed and Wireless Networks This page intentionally left blank DATA COMMUNICATION PRINCIPLES For Fixed and Wireless Networks Aftab Ahmad KLUWER ACADEMIC PUBLISHERS NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOW eBook ISBN: 0-306-47793-9 Print ISBN: 1-4020-7328-3 ©2002 Kluwer Academic Publishers New York, Boston, Dordrecht, London, Moscow Print ©2003 Kluwer Academic Publishers All rights reserved No part of this eBook may be reproduced or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without written consent from the Publisher Created in the United States of America Visit Kluwer Online at: http://kluweronline.com and Kluwer's eBookstore at: http://ebooks.kluweronline.com Dordrecht NOTE TO INSTRUCTORS As an aid to instructors interested in teaching this book as a course, exercises suitable for use in a classroom setting are available by contacting the author at Aftab@ieee.org. This page intentionally left blank To my parents This page intentionally left blank [...]... components are: 1 The Computer System 2 The Communications System 3 The Networking System Data Networks There is a myriad of terms used to describe a computer communications network Computer Networks, Networks, Communications Networks, Telecommunications Networks, Packet Switched Networks, Networking Systems and Data Networking Systems are all among the terms used The terms data network used to be more descriptive... engineering, telecommunications, information systems, and other majors that require an elementary to medium level knowledge of data communications principles Much of the material has been used to offer graduate and undergraduate level courses in some of the above areas The book is a compilation from lecture notes with some addition The approach adopted is rather straightforward; define a data network as... 257 257 258 262 264 266 References 267 Index 273 Preface In spite of the fact that the electronic communication systems started as data communication systems, much of their advancement has been in the field of voice For decades, the Public Switched Telecommunications Network (PSTN) has set standards for communication of information all over the world Things started changing only towards the closing... that time, data meant store and forward type of information that had no real-time content Examples of such information are file, email and logon programs With time, definition of data has changed (see Chapter 3), and so has the definition of data networks A data network now includes all of the above The telephone network could be seen as an exception, even though it is also been used as data network... In essence, the communication has to be broken into well-defined functions so that each function can be standardized However, due to the diverse nature of the data to be communicated, it may not be a simple task to break the needs into same parts for all type of data Let’s take two examples in the next section: voice and file transfer 1.3.1 Example 1 - Communication of Voice In a voice communications... (IEEE) 2.6 Summary 2.7 Review Questions 42 42 43 45 46 47 48 49 49 50 50 50 51 52 53 55 3 Network and User Data 56 3.1 The Network Data 57 3.2 The Physical Layer Data 3.2.1 Sequence of Events and Definitions 57 67 3.2.2 Modulation of data and signals 70 3.2.3 Digital Encoding of Data 71 3.2.4 Non-Return to Zero (NRZ) 72 3.2.5 Multilevel Encoding 73 3.2.6 Manchester Coding 74 3.2.7 General Characteristics... underwater) A device known as MODEM (Modulator/demodulator) is an example of a communications system In designing a MODEM for telephone line, the main challenge comes in utilizing the limited telephone bandwidth to transfer information at a maximum possible rate The job of communication system design lies with the communications engineer A communications engineer has to study the characteristics of information,... these machines are capable of processing data at speeds that could easily take care of the requirements of interactive information The introduction of IMT-2000 systems in wireless arena has reduced the gap in wireless, voice and data Now we talk about multimedia wireless networks that could use Internet as a backbone Consequently, the entire meaning of data and communications has changed to include real-time... International Telecommunications Union (ITU) 2.5.2 The Internet Society 2.5.3 International Organization for Standardization (ISO) 2.5.4 European Telecommunications Standards Institute (ETSI) 2.5.5 American National Standard Institute (ANSI) 2.5.6 Institute of Electrical and Electronic Engineers (IEEE) 2.6 Summary 2.7 Review Questions 42 42 43 45 46 47 48 49 49 50 50 50 51 52 53 55 3 Network and User Data 56...Table of Contents Preface xv 1 Computer Communications Networks - Introduction 1.1 Main Components 1.1.1 The Computer System 1.1.2 The Communications System 1.1.3 The Networking System 1.2 Network Development Example 1.2.1 Three Role Players 1.2.2 Network Design 1.3 Standardization 1.3.1 Example 1 - Communication of Voice 1.3.2 Example 2 - File Transfer 1.4 Classification . DATA COMMUNICATION PRINCIPLES For Fixed and Wireless Networks This page intentionally left blank DATA COMMUNICATION PRINCIPLES For Fixed. engineering, telecommunications, information systems, and other majors that require an elementary to medium level knowledge of data communications principles.