Table Of ContentUndergraduate Topics in Computer
Science
Undergraduate Topics in Computer Science (UTiCS) delivers high-quality instructional content for
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For further volumes:
http://www.springer.com/series/7592
John Cowley
Communications
and Networking
An Introduction
Second Edition
John Cowley
Kingswinford, West Midlands, UK
Series editor
Ian Mackie
Advisory board
Samson Abramsky, University of Oxford, Oxford, UK
Karin Breitman, Ponti fi cal Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil
Chris Hankin, Imperial College London, London, UK
Dexter Kozen, Cornell University, Ithaca, USA
Andrew Pitts, University of Cambridge, Cambridge, UK
Hanne Riis Nielson, Technical University of Denmark, Kongens Lyngby, Denmark
Steven Skiena, Stony Brook University, Stony Brook, USA
Iain Stewart, University of Durham, Durham, UK
ISSN 1863-7310 Undergraduate Topics in Computer Science
ISBN 978-1-4471-4356-7 ISBN 978-1-4471-4357-4 (eBook)
DOI 10.1007/978-1-4471-4357-4
Springer London Heidelberg New York Dordrecht
Library of Congress Control Number: 2012948286
© Springer-Verlag London 2012
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Preface
Overview
Communications and Networking: An Introduction, Second Edition provides a clear
and easy to follow treatment of the subject, written speci fi cally for undergraduates
who have no previous experience in the fi eld.
Organisation and Features
• Topics retained from the previous edition include:
– Networking models and standards, local area and wide area networks, network
protocols, TCP/IP-based networks and network management
– Plenty of material on wireless communications, both fi xed and mobile
– Authoritative coverage of network security
– Many explanatory diagrams
– Comprehensive glossary
• All these topics continue to be important and relevant today.
The new edition contains several changes and additions.
• Several sections have been added to illustrate the most recent developments in
networking and communications. The most signi fi cant additions are the following:
– There is a much greater emphasis on mobile computing, particularly modern
mobile phones.
– The section on Internet protocol version 6 (IPv6) has been considerably
expanded.
– New threats to data and new ways of countering these have been included in
the chapter on network security.
– There is a greater emphasis on security in other chapters too.
– Grid computing, cloud computing, microblogging, mobile ad hoc networks,
near fi eld communication, Power over Ethernet and the Ground Positioning
System (GPS) are covered in the new edition.
v
vi Preface
• Mistakes and typos have been corrected, and some concepts have been further
clari fi ed, based on observations received from readers.
• Coverage of some older technologies has been reduced.
• The glossary has been revised.
• The language used has been simpli fi ed to some extent, for the bene fi t of non-
English speakers.
• A number of new diagrams have been added, some modi fi ed and a few removed.
Target Audiences
Primary
First- and second-level undergraduates studying modules on communications and/or
networks.
Secondary
First- and second-level undergraduates studying modules that contain some material
on communications and/or networks.
Suggestions to the Instructor
• Base your lectures on the PowerPoint slides.
• Use the end-of-chapter questions and supplementary exercises for tutorials and/or
self study and class tests.
• Use this book itself for self study (under your guidance if necessary).
Supplementary Resources
The following supplementary resources are hosted on a website:
• PowerPoint teaching slides (updated so as to complement the new edition)
• Revised solutions to the end-of-chapter questions
• Updated supplementary exercises with solutions
Why Should I Buy/Recommend This Book?
The author takes a step-by-step approach, with examples and exercises designed to
give the reader increased con fi dence in using and understanding communications
systems. The text takes the reader through the essentials of networking and com-
munications technologies and provides a comprehensive, reliable and thorough
treatment of the subject. It is organised in such a way that readers without a strong
knowledge of the subject matter can grasp the material quickly.
Contents
1 Introduction ............................................................................................. 1
1.1 What Is a Network? ......................................................................... 1
1.2 Types of Networks ........................................................................... 1
1.3 Reasons for Networks ...................................................................... 3
1.4 Communication Between Computers .............................................. 3
1.4.1 Source, Destination and Transmission Medium .................. 3
1.4.2 Packet ................................................................................... 3
1.4.3 Protocol ................................................................................ 4
1.5 Summary .......................................................................................... 4
1.6 Questions .......................................................................................... 4
2 Communications Technologies ............................................................... 5
2.1 Serial and Parallel Communications ................................................ 5
2.2 Asynchronous and Synchronous Communications ......................... 7
2.2.1 Asynchronous Transmission ................................................ 7
2.2.2 Synchronous Transmission .................................................. 8
2.3 Simplex, Half-Duplex and Full-Duplex Communications............... 8
2.4 Data Rate, Bandwidth and Throughput ........................................... 10
2.4.1 Data Rate .............................................................................. 10
2.4.2 Data Transfer Calculations ................................................... 10
2.4.3 Throughput ........................................................................... 11
2.4.4 Bandwidth ............................................................................ 11
2.5 Modulation and Encoding ................................................................ 12
2.5.1 Amplitude Modulation, Frequency Modulation
and Phase Modulation .......................................................... 12
2.5.2 Codes for Transmitting Digital Data
Using Digital Signals ........................................................... 12
2.6 Error Control Methods ..................................................................... 14
2.6.1 Automatic Repeat Request ................................................... 14
2.6.2 Forward Error Correction ..................................................... 17
vii
viii Contents
2.7 Switched Connections .................................................................... 18
2.7.1 Circuit Switching ............................................................. 18
2.7.2 Message Switching .......................................................... 19
2.7.3 Packet Switching .............................................................. 20
2.8 Multiplexing ................................................................................... 21
2.8.1 Time Division Multiplexing ............................................. 21
2.8.2 Frequency Division Multiplexing .................................... 22
2.8.3 Wavelength Division Multiplexing .................................. 22
2.9 Topologies Used in Networking .................................................... 23
2.9.1 Bus ................................................................................... 23
2.9.2 Ring .................................................................................. 23
2.9.3 Star ................................................................................... 24
2.9.4 Tree (Hierarchical) ........................................................... 24
2.9.5 Mesh ................................................................................. 26
2.10 Network Transmission Media ........................................................ 26
2.10.1 Copper Cable ................................................................... 26
2.10.2 Fibre-Optic Cable ............................................................. 29
2.10.3 Wireless Media ................................................................ 30
2.11 Summary ........................................................................................ 33
2.12 Questions ........................................................................................ 33
3 Networking Models and Standards ....................................................... 35
3.1 Layering of Networks .................................................................... 35
3.1.1 Advantages of Layering ................................................... 36
3.2 OSI 7-Layer Reference Model ....................................................... 36
3.2.1 Physical Layer .................................................................. 37
3.2.2 Data-Link Layer ............................................................... 38
3.2.3 Network Layer ................................................................. 38
3.2.4 Transport Layer ................................................................ 38
3.2.5 Session Layer ................................................................... 38
3.2.6 Presentation Layer ........................................................... 39
3.2.7 Application Layer ............................................................ 39
3.3 Encapsulation ................................................................................. 39
3.4 TCP/IP Model ................................................................................ 41
3.5 The OSI and TCP/IP Models Compared ....................................... 41
3.6 Networking Standards .................................................................... 43
3.6.1 Networking Standards Bodies .......................................... 43
3.7 Summary ........................................................................................ 44
3.8 Questions ........................................................................................ 44
4 Local Area Networks .............................................................................. 47
4.1 Building LANs ............................................................................... 47
4.1.1 Peer-to-Peer and Client–Server LANs ............................. 47
4.1.2 Transmission Medium ...................................................... 49
4.1.3 Components and Devices ................................................. 50
Contents ix
4.2 Types of Wired LAN ...................................................................... 56
4.2.1 Logical Link Control and MAC Sub-layers ..................... 56
4.2.2 Ethernet ............................................................................ 56
4.2.3 Other Types of Wired LAN .............................................. 60
4.3 Storage Area Network .................................................................... 61
4.4 Grid Computing ............................................................................. 62
4.5 Summary ........................................................................................ 63
4.6 Questions ........................................................................................ 64
5 Wide Area Networks ............................................................................... 65
5.1 General Characteristics of WANs .................................................. 65
5.2 Public Switched Telephone Network ............................................. 66
5.3 Frame Relay ................................................................................... 66
5.4 Integrated Services Digital Network .............................................. 68
5.5 Leased Lines .................................................................................. 69
5.6 Digital Subscriber Line .................................................................. 70
5.7 Cable Modems ............................................................................... 72
5.8 Remote Access to LANs ................................................................ 72
5.8.1 Remote Node ................................................................... 72
5.8.2 Remote Control ................................................................ 73
5.8.3 Remote Working via the Web .......................................... 73
5.9 Routers ........................................................................................... 73
5.10 ATM in the WAN ........................................................................... 77
5.11 Ethernet in the WAN ...................................................................... 78
5.12 Cloud Computing ........................................................................... 78
5.12.1 Advantages and Disadvantages
of Cloud Computing ........................................................ 79
5.13 Summary ........................................................................................ 79
5.14 Questions ........................................................................................ 80
6 Network Protocols ................................................................................... 81
6.1 Internet Protocol ............................................................................. 81
6.1.1 IPv4 Addresses ................................................................. 81
6.1.2 Reserved Addresses ......................................................... 83
6.1.3 Address Resolution Protocol ............................................ 85
6.1.4 Fragmentation .................................................................. 85
6.1.5 Ways of Assigning IP Addresses ..................................... 87
6.1.6 Shortage of IP Addresses ................................................. 90
6.1.7 IP Version 6 ...................................................................... 94
6.1.8 Internet Control Message Protocol .................................. 98
6.2 The Transport Layer of TCP/IP ..................................................... 99
6.2.1 Introduction to Transmission Control Protocol ............... 99
6.2.2 Connection-Oriented and Connectionless Working ......... 100
6.2.3 Flow Control .................................................................... 100
6.2.4 Three-Way Handshake and Four-Way Tear Down .......... 100
6.2.5 Windowing ....................................................................... 101
x Contents
6.2.6 Port Numbers ................................................................... 102
6.2.7 User Datagram Protocol ................................................... 104
6.3 High-Level Data Link Control ....................................................... 104
6.4 Multiprotocol Label Switching ...................................................... 105
6.5 Routing Protocols........................................................................... 106
6.6 Summary ........................................................................................ 107
6.7 Questions ........................................................................................ 108
7 Internet Application-Layer Protocols ................................................... 111
7.1 Client–Server Applications ............................................................ 111
7.2 Domain Name System ................................................................... 112
7.2.1 Difficulties with Using Numerical IP Addresses ............. 112
7.2.2 Domain Name Server ....................................................... 113
7.3 World Wide Web and HyperText Transfer Protocol ...................... 114
7.3.1 HyperText Markup Language .......................................... 115
7.3.2 Hyperlinks ........................................................................ 116
7.3.3 Web Browser .................................................................... 116
7.3.4 HyperText Transfer Protocol ............................................ 116
7.4 Remote Access and the Telnet Protocol ......................................... 117
7.4.1 Encapsulation of Telnet Commands ................................ 117
7.5 File Transfer and the File Transfer Protocol .................................. 120
7.5.1 Anonymous FTP .............................................................. 121
7.5.2 TCP Control and Data Connections ................................. 122
7.5.3 FTP Transfer Modes ........................................................ 123
7.6 Electronic Mail ............................................................................... 123
7.6.1 Transmitting a Message to an E-mail Server ................... 125
7.6.2 E-mail Standards .............................................................. 126
7.6.3 Fetching the E-mail from the Server ................................ 128
7.7 Delivery of Streamed Content over the Internet ............................ 130
7.7.1 Streaming Audio .............................................................. 130
7.7.2 Voice over IP .................................................................... 131
7.8 P2P File Sharing ............................................................................ 132
7.9 Instant Messaging .......................................................................... 132
7.10 Microblogging ................................................................................ 133
7.11 Summary ........................................................................................ 133
7.12 Questions ........................................................................................ 133
8 Network Security .................................................................................... 137
8.1 Authentication, Authorisation, Confidentiality,
Non-repudiation and Integrity ........................................................ 137
8.1.1 Authentication .................................................................. 137
8.1.2 Authorisation .................................................................... 139
8.1.3 Confidentiality.................................................................. 140
8.1.4 Message Digests ............................................................... 143
8.1.5 Non-repudiation ............................................................... 144
8.1.6 Message Integrity ............................................................. 144
8.1.7 Security Policy ................................................................. 144
