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ACRONYMS

ADSL Asymmetric Digital Subscriber Line

AES Advanced Encryption Standard AM Amplitude Modulation ANSI American National Standard

Institute API Application Programming

Interface ARQ Automatic Repeat Request ASCII American Standard Code for

Information Interchange ASK Amplitude-Shift Keying ATM Asynchronous Transfer Mode BGP Border Gateway Protocol CDMA Code Division Multiple Access CSMA/CD Carrier Sense Multiple Access with

Collision Detection CPE Customer Premises Equipment CRC Cyclic Redundancy Check DES Data Encryption Standard DDP Distributed Data Processing DNS Domain Name System DWDM Dense Wavelength Division

Multiplexing FCC Federal Communications

Commission FCS Frame Check Sequence FDM Frequency-Division Multiplexing FDMA Frequency Division Multiple

Access FSK Frequency-Shift Keying FTP File Transfer Protocol FM Frequency Modulation HDLC High-Level Data Link Control HTML HyperText Markup Language HTTP Hypertext Transfer Protocol IAB Internet Architecture Board IEEE Institute of Electrical and

Electronics Engineers IETF Internet Engineering Task Force IP Internet Protocol IRA International Reference Alphabet ISP Internet Service Provider IT Information Technology ITU International Telecommunication

Union ITU-T ITU Telecommunication

Standardization Sector

LAN Local Area Network LEOS Low-Earth-Orbiting Satellite LLC Logical Link Control MAC Medium Access Control MAN Metropolitan Area Network MEOS Medium-Earth-Orbiting Satellite MIB Management Information Base MIME Multipurpose Internet Mail

Extension NAP Network Access Point NSP Network Service Provider OSI Open Systems Interconnection OSPF Open Shortest Path First PBX Private Branch Exchange PCM Pulse Code Modulation PDF Portable Document Format PDU Protocol Data Unit POP Point of Presence PSK Phase-Shift Keying PSTN Public Switched Telephone

Network QoS Quality of Service SAN Storage Area Network SAP Service Access Point SDH Synchronous Digital Hierarchy SIP Session Initiation Protocol SMTP Simple Mail Transfer Protocol SNMP Simple Network Management

Protocol SOA Service-Oriented Architecture SONET Synchronous Optical Network STP Shielded Twisted Pair TCP Transmission Control Protocol TDM Time-Division Multiplexing TDMA Time Division Multiple Access UC Unified Communications UDP User Datagram Protocol URI Universal Resource Identifier URL Uniform Resource Locator UTP Unshielded Twisted Pair VAN Value-Added Network VoIP Voice Over IP VPN Virtual Private Network WAN Wide Area Network WDM Wavelength-Division Multiplexing WAP Wireless Application Protocol WWW World Wide Web XML Extensible Markup Language

THE WILLIAM STALLINGS BOOKS ON COMPUTER AND DATA COMMUNICATIONS TECHNOLOGY

DATA AND COMPUTER COMMUNICATIONS, NINTH EDITION A comprehensive survey that has become the standard in the field, covering (1) data communications, including transmission, media, signal encoding, link control, and multiplexing; (2) communication networks, including circuit- and packet-switching, frame relay, ATM, and LANs; (3) the TCP/IP suite, including IPv6, TCP, MIME, and HTTP, as well as a detailed treatment of network security. Received the 2007 Text and Academic Authors Association (TAA) award for the best Computer Science and Engineering Textbook of the year. ISBN 978-0-13-139205-2

OPERATING SYSTEMS, SEVENTH EDITION A state-of-the art survey of operating system principles. Covers fundamental technology as well as contemporary design issues, such as threads, microkernels, SMPs, real-time systems, multiprocessor scheduling, embedded OSs, distributed systems, clusters, security, and object-oriented design. Third, fourth, and sixth editions received the TAA award for the best Computer Science and Engineering Textbook of the year. ISBN 978-0-13-230998-1

CRYPTOGRAPHY AND NETWORK SECURITY, SEVENTH EDITION A tutorial and survey on network security technology. Each of the basic building blocks of network security, including conventional and public-key cryptography, authentication, and digital signatures, is covered. Thorough mathematical background for such algorithms as AES and RSA. The book covers important network security tools and applications, including S/MIME, IP security, Kerberos, SSL/TLS, SET, and X509v3. In addition, methods for countering hackers and viruses are explored. Second edition received the TAA award for the best Computer Science and Engineering Textbook of 1999. ISBN 978-0-13-609704-4

COMPUTER ORGANIZATION AND ARCHITECTURE, NINTH EDITION A unified view of this broad field. Covers fundamentals such as CPU, control unit, microprogramming, instruction set, I/O, and memory. Also covers advanced topics such as multicore, superscalar, and parallel organization. Four-time winner of the TAA award for the best Computer Science and Engineering Textbook of the year. ISBN 978-0-13-293633-0

COMPUTER SECURITY, SECOND EDITION (with Lawrie Brown) A comprehensive treatment of computer security technology, including algorithms, protocols, and applications. Covers cryptography, authentication, access control, database security, intrusion detection and prevention, malicious software, denial of service, firewalls, software security, physical security, human factors, auditing, legal and ethical aspects, and trusted systems. Received the 2008 Text and Academic Authors Association (TAA) award for the best Computer Science and Engineering Textbook of the year. ISBN 978-0-13-277506-9

NETWORK SECURITY ESSENTIALS, FOURTH EDITION A tutorial and survey on network security technology. The book covers important network security tools and applications, including S/MIME, IP security, Kerberos, SSL/TLS, SET, and X509v3. In addition, methods for countering hackers and viruses are explored. ISBN 978-0-13-610805-4

WIRELESS COMMUNICATIONS AND NETWORKS, SECOND EDITION

A comprehensive, state-of-the art survey. Covers fundamental wireless communications topics, including antennas and propagation, signal encoding techniques, spread spectrum, and error correction techniques. Examines satellite, cellular, wireless local loop networks and wireless LANs, including Bluetooth and 802.11. Covers Mobile IP and WAP. ISBN 978-0-13-191835-1

COMPUTER NETWORKS WITH INTERNET PROTOCOLS AND TECHNOLOGY

An up-to-date survey of developments in the area of Internet-based protocols and algorithms. Using a top-down approach, this book covers applications, transport layer, Internet QoS, Internet routing, data link layer and computer networks, security, and network management. ISBN 978-0-13-141098-5

Business Data CommuniCations: infrastruCture, networking anD seCurity seventh eDition

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Library of Congress Cataloging-in-Publication Data

Stallings, William. Business data communications : infrastructure, networking and security / William Stallings,

Thomas Case.—7th ed. p. cm. ISBN-13: 978-0-13-302389-3 (alk. paper) ISBN-10: 0-13-302389-3 (alk. paper) 1. Business—Data processing. 2. Business—Communication systems—Data processing. 3. Local area networks (Computer networks) 4. Data transmission systems. 5. Business enterprises—Computer networks. 6. Electronic commerce. I. Case, Thomas. II. Title. HF5548.2.S7728 2013 004.6—dc23 2012026915

ISBN-10: 0-13-302389-3 ISBN-13: 978-0-13-302389-3

For my loving wife Tricia —Ws

To Carol, Ethan, and Maryn for their continuous inspiration and love —TC

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Contents Online Resources xii

Preface xiii

About the Authors xx

Chapter 0 Reader’s and Instructor’s Guide 1

0.1 Outline of This Book 2 0.2 Topic Ordering 2 0.3 Internet and Web Resources 3 0.4 Useful Publications 4

Chapter 1 Introduction 6

1.1 Information and Communication 7 1.2 Data Communications and Networking for Today’s Enterprise 8 1.3 Convergence and Unified Communications 12 1.4 The Nature of Business Information Requirements 19 1.5 The Transmission of Information 21 1.6 Distributed Data Processing 22 1.7 The Internet and Distributed Applications 23 1.8 Networks 25 1.9 Management Issues 31 1.10 Standards 33 1.11 Key Terms, Review Questions, and Problems 34 Appendix 1A Prefixes for Numerical Units 35

Case Study I Unified Communications at Boeing (ONLINE)

Part One requirements 37

Chapter 2 Business Information 37

2.1 Audio 39 2.2 Data 42 2.3 Image 45 2.4 Video 50 2.5 Performance Measures 53 Application Note: File Sizes 60 2.6 Summary 61 2.7 Key Terms, Review Questions, and Problems 61

Case Study II CORE Credit Union (ONLINE)

Chapter 3 Distributed Data Processing 65

3.1 Centralized Versus Distributed Processing 67 3.2 Forms of Distributed Data Processing 82 3.3 Distributed Data 85 3.4 Networking Implications of DDP 91 3.5 Big Data Infrastructure Considerations 93 Application Note: Distributed Computing Support 95

v

vi Contents

3.6 Summary 96 3.7 Key Terms, Review Questions, and Problems 97

Case Study III Managing Massive Data Warehouses at MasterCard International (ONLINE)

Part twO Data COmmuniCatiOns 101

Chapter 4 Data Transmission 101

4.1 Signals for Conveying Information 102 4.2 Transmission Impairments and Channel Capacity 113 Application Note: Analog Signals 120 4.3 Summary 122 4.4 Key Terms, Review Questions, and Problems 122

Chapter 5 Data Communication Fundamentals 124

5.1 Analog and Digital Data Communications 125 5.2 Data Encoding Techniques 129 5.3 Asynchronous and Synchronous Transmission 141 5.4 Error Detection 145 Application Note: Devices, Encoding, Communication Parameters, and Protocols 148 5.5 Summary 149 5.6 Key Terms, Review Questions, and Problems 150

Chapter 6 Data Link Control and Multiplexing 153

6.1 Flow Control and Error Control 155 6.2 Motivation for Multiplexing 157 6.3 Frequency-Division Multiplexing 158 6.4 Synchronous Time-Division Multiplexing 165 Application Note: Changing Communications 172 6.5 Summary 173 6.6 Key Terms, Review Questions, and Problems 174 Appendix 6A High Level Data Link Control Protocol 176

Case Study IV Broadband Access: Global and Local Issues (ONLINE)

Part three the internet anD DistributeD aPPliCatiOns 182

Chapter 7 The Internet 182

7.1 The Structure of the Internet 183 7.2 Internet Domains 193 7.3 Dynamic Host Configuration Protocol 199 Application Note: Fitting DNS into Your Organizational Structure 202 7.4 Summary 203 7.5 Key Terms, Review Questions, and Problems 204

Case Study V Net Neutrality (ONLINE)

Chapter 8 TCP/IP 206

8.1 A Simple Protocol Architecture 208 8.2 The TCP/IP Architecture 215 8.3 Internetworking 222 8.4 Virtual Private Networks and IP Security 226 Application Note: Practical Guide to Networking 230 8.5 Summary 231

Contents vii

8.6 Key Terms, Review Questions, and Problems 232 Appendix 8A TCP, UDP, and IP Details 235 Appendix 8B The Trivial File Transfer Protocol 239

Chapter 9 Client/Server, Intranet, and Cloud Computing 244

9.1 The Growth of Client/Server Computing 245 9.2 Client/Server Applications 248 9.3 Middleware 254 9.4 Intranets 262 9.5 Extranets 266 9.6 Service-Oriented Architecture 267 9.7 Cloud Computing 270 Application Note: To Be Fat or Thin—That Is the Question 276 9.8 Summary 278 9.9 Key Terms, Review Questions, and Problems 279

Case Study VI Shifting Sands: Chevron’s Migration to the Cloud (ONLINE)

Chapter 10 Internet-Based Applications 281

10.1 Electronic Mail 282 10.2 Web Access and HTTP 292 10.3 Web Security 298 10.4 Multimedia Applications 300 10.5 Acceptable Use Policies 303 Application Note: To Serve or Not to Serve 306 10.6 Summary 307 10.7 Key Terms, Review Questions, and Problems 308

Case Study VII E-Business at Guardian Life (ONLINE)

Chapter 11 Internet Operation 310

11.1 Internet Addressing 311 11.2 Internet Routing Protocols 316 11.3 Multicasting 321 11.4 Quality of Service 324 11.5 Differentiated Services 328 11.6 Service Level Agreements 332 11.7 IP Performance Metrics 334 Application Note: Where Does My Network Address Come From? 336 11.8 Summary 337 11.9 Key Terms, Review Questions, and Problems 338

Part FOur lOCal area netwOrKs 340

Chapter 12 LAN Architecture and Infrastructure 340

12.1 Background 341 12.2 LAN Configuration 346 12.3 Guided Transmission Media 349 12.4 LAN Protocol Architecture 358 Application Note: Cabling Infrastructure 363 12.5 Summary 365 12.6 Key Terms, Review Questions, and Problems 365 Appendix 12A Decibels and Signal Strength 367

Case Study VIII Carlson Companies (ONLINE)

viii Contents

Chapter 13 Ethernet, Switches, and Virtual LANs 370

13.1 Traditional Ethernet 371 13.2 Bridges, Hubs, and Switches 377 13.3 High-Speed Ethernet 384 13.4 Virtual LANs 391 13.5 Power over Ethernet 396 Application Note: Networking with Ethernet 398 13.6 Summary 399 13.7 Key Terms, Review Questions, and Problems 400

Chapter 14 Wireless LANs 402

14.1 Overview 403 14.2 Wi-Fi Architecture and Services 406 14.3 IEEE 802.11 MAC and Physical Layer Standards 411 14.4 Gigabit WLANs 417 14.5 IEEE 802.11 Security Considerations 418 Application Note: Deploying WLANs 419 14.6 Summary 421 14.7 Key Terms, Review Questions, and Problems 421

Case Study IX St. Luke’s Health Care System: Using Mobility to Advance Health Care Delivery (ONLINE)

Part Five wiDe area netwOrKs 423

Chapter 15 WAN Technology and Protocols 423

15.1 Switching Techniques 424 15.2 Circuit-Switching Networks 426 15.3 Packet-Switching Networks 431 15.4 Traditional Wide Area Network Alternatives 436 15.5 Voice Over IP 440 15.6 Presence 445 15.7 Summary 447 15.8 Key Terms, Review Questions, and Problems 448

Chapter 16 WAN Services 450

16.1 Wide Area Networking Alternatives 452 16.2 Frame Relay 456 16.3 Asynchronous Transfer Mode (ATM) 463 16.4 Multiprotocol Label Switching (MPLS) 470 16.5 Wide Area Ethernet 473 Application Note: Off-Site Connectivity Solutions 475 16.6 Summary 476 16.7 Key Terms, Review Questions, and Problems 477

Chapter 17 Wireless WANs 479

17.1 Cellular Wireless Network 481 17.2 Multiple Access 488 17.3 Third-Generation Wireless Communication 491 17.4 Fourth-Generation Wireless Communication 496 17.5 Satellite Communications 499 Application Note: Laptops, Netbooks, PDAs, and Cell Phones 505

Contents ix

17.6 Summary 507 17.7 Key Terms, Review Questions, and Problems 507

Case Study X Choice Hotels (ONLINE)

Part six management issues 510

Chapter 18 Computer and Network Security Threats 510

18.1 Computer Security Concepts 511 18.2 Threats, Attacks, and Assets 513 18.3 Intruders 518 18.4 Malicious Software Overview 522 18.5 Viruses, Worms, Bots, and Spam 526 18.6 Keyloggers, Phishing, Spyware 536 18.7 Computer Security Trends 538 18.8 Summary 540 18.9 Key Terms, Review Questions, and Problems 540

Chapter 19 Computer and Network Security Techniques 544

19.1 Virtual Private Networks and IPsec 545 19.2 SSL and TLS 548 19.3 Wi-Fi Protected Access 550 19.4 Intrusion Detection 553 19.5 Firewalls 556 19.6 Malware Defense 561 Application Note: Security Layers 563 19.7 Summary 565 19.8 Key Terms, Review Questions, and Problems 566

Case Study XI Cloud Computing (In)Security (ONLINE)

Chapter 20 Network Management (ONLINE)

Chapter 21 Network Planning and Design (ONLINE)

Appendix A Projects for Teaching Business Data Communications 569

A.1 Animations and Animation Projects 570 A.2 Practical Exercises 571 A.3 Wireshark Projects 572 A.4 Research Projects 572 A.5 Security Case Studies 573 A.6 Reading/Report Assignments 573 A.7 Writing Assignments 573

Glossary 574

References 581

Index 584

x Contents

ONLINE CHAPTERS AND APPENDICES1

1Online chapters, appendices, and other documents are Premium Content, available via the access card at the front of this book.

Chapter 20 Network Management (ONLINE)

20.1 Network Management Requirements 20.2 Network Management Systems 20.3 Simple Network Management Protocol (SNMP) Application Note: How Much Management? 20.4 Key Terms, Review Questions, and Problems

Chapter 21 Network Planning and Design (ONLINE)

21.1 The Project Environment—The Big Picture 21.2 Planning 21.3 Design Techniques 21.4 Some Capacity Planning and Network Design Tools Appendix 21A Some Simple Design Algorithms Appendix 21B Selling Books Online—A Case Study

Appendix B Standards Organizations

B.1 The Importance of Standards B.2 Standards and Regulation B.3 Standards-Setting Organizations

Appendix C Uniform Resource Locators (URLs) and Uniform Resource Identifiers (URIs)

C.1 Uniform Resource Locator C.2 Uniform Resource Identifier C.3 To Learn More

Appendix D The International Reference Alphabet

Appendix E The TCP/IP Checksum

E.1 Ones-Complement Addition E.2 Use in TCP and IP

Appendix F IBM’s System Network Architecture (SNA)

F.1 Network Architecture F.2 Advanced Program-to-Program Communication F.3 Protocol Architecture

Appendix G Fibre Channel

G.1 Fibre Channel Elements G.2 Fibre Channel Protocol Architecture

Appendix H Bluetooth

H.1 Bluetooth Applications H.2 Bluetooth Standards Documents H.3 Protocol Architecture H.4 Usage Models H.5 Piconets and Scatternets

Contents xi

Appendix I Multipath Interference and Orthogonal Frequency-Division Multiplexing (OFDM)

I.1 Multipath Interference I.2 Orthogonal Frequency-Division Multiplexing

Appendix J Cryptographic Algorithms

J.1 Symmetric Encryption J.2 Public-Key Cryptography J.3 Message Authentication and Hash Functions J.4 Secure Hash Functions

Appendix K Sliding-Window Flow Control and Error Control

K.1 Flow Control K.2 Error Control

Appendix L The OSI Model

L.1 The Model L.2 The OSI Layers

Appendix M Code-Division Multiple Access

xii

online resourCes

Site Location Description

Companion Web site WilliamStallings.com/BusinessDataComm Student Resources link: Useful links and documents for students

Instructor Resources link: Useful links and documents for instructors

Premium Content Click on Premium Content link at Companion Web site or at pearsonhighered .com/stallings and enter the student access code found on the card in the front of the book

Online chapters, appendices, and other documents that supplement the book

Instructor Resource Center (IRC)

Click on Pearson Resources for Instructors link at Companion Web site or on Instructor Resource link at pearsonhighered.com/stallings

Solutions manual, projects manual, slides, and other useful documents

Computer Science Student Resource Site

ComputerScienceStudent.com Useful links and documents for computer science students

xiii

PrefaCe what’s new in the seventh eDitiOn

In the four years since the sixth edition of this book was published, the field has seen contin- ued innovations and improvements. In this new edition, we try to capture these changes while maintaining a broad and comprehensive coverage of the entire field. To begin the process of revision, the sixth edition of this book was extensively reviewed by a number of professors who teach the subject and by professionals working in the field. The result is that, in many places, the narrative has been clarified and tightened, and illustrations have been improved. One noteworthy result of this review process, is that the chapter order has been restructured; see Chapter 0 for a discussion.

Beyond these refinements to improve pedagogy and user-friendliness, there have been substantive changes throughout the book. Much of the material has been revised and new material has been added. The most noteworthy changes are as follows:

• Cloud computing: Cloud computing has become a vital and essential tool in business IT. Cloud computing concepts are covered in a number of chapters throughout the book.

• Big data: A new section examines the creation, manipulation, and management of very large data sets (measured in terabytes, petabytes, exabytes, etc.) and the facilities in which these are stored.

• Fourth-generation (4G) mobile networks: 4G networks continue to expand worldwide and a section covering this recent technology has been added.

• Dynamic Host Configuration Protocol (DHCP): DHCP is a widely used protocol that enables dynamic IP address assignment. A new section covers this protocol.

• MPLS: New to this edition is a section devoted to Multiprotocol Label Switching (MPLS), which is becoming increasingly important on the Internet and other IP-based networks, as well as in telecommunications networks.

• Evolution of Ethernet: The book covers new developments in Ethernet technology and application, including Power over Ethernet (PoE) and Wide Area Ethernet (WAE).

• Virtual LANs (VLANs): VLAN technology is covered, as well is the IEEE 802.1Q standard.

• Electronic mail: The section on e-mail in Chapter 10 has been expanded to include a discussion of the standard Internet mail architecture.

• Multimedia applications: A new discussion of this topic is in Chapter 10. • Acceptable use policies: A new section on acceptable use policies for e-mail, Web, and

Internet applications is in Chapter 10. • Internet addressing: The section on Internet addressing has been updated and expanded

to include CIDR and IPv6 addresses. • Multicasting: A new section on multicasting, which is increasingly important in the

business environment, has been added. • VoIP: Voice over IP (VoIP) is increasingly replacing traditional voice services. A new

section in Chapter 15 discusses technology and service aspects.

xiv PrefaCe

• Presence information and services: The increased use of instant messaging and VoIP, plus the increased use of collaboration services, is supported by presence services now becoming available. A new section in Chapter 15 explores presence information and services.

With each new edition it is a struggle to maintain a reasonable page count while adding new material. In part, this objective is realized by eliminating obsolete material and tighten- ing the narrative. For this edition, chapters and appendices that are of less general interest have been moved online, as individual PDF files. This has allowed an expansion of material without the corresponding increase in size and price.

Finally, the number of authors of this book has doubled! Our backgrounds and expe- rience are complementary in many respects and we are confident that the partnership has produced a book that is even more useful to the business student than the preceding edition.

baCKgrOunD

Technological developments and the widespread acceptance of standards are transforming the ways in which information is used to support the business function. In addition to the traditional communications requirements for voice and data (meaning text and numerical data), there is now the need to deal with pictorial images and video information. These four types of information (voice, data, image, and video) are essential to the survival of any busi- ness in today’s competitive international environment. What is needed in a business data communications book is a treatment not just of data communications but also of informa- tion communications for the business environment.

Information communications and computer networking have become essential to the functioning of today’s businesses, large and small. Furthermore, they have become a major and growing cost to organizations. Management and staff need a thorough understanding of information communications in order to assess needs; plan for the introduction of products, services, and systems; and manage the systems and technical personnel that operate them. This understanding must comprise the following:

• Technology: The underlying technology of information communications facilities, networking systems, and communications software

• Architecture: The way in which hardware, software, and services can be organized to provide computer and terminal interconnection

• Applications: How information communications and networking systems can meet the requirements of today’s businesses

aPPrOaCh

The purpose of this text is to present the concepts of information communications in a way that relates specifically to the business environment and to the concerns of business manage- ment and staff. To this end, the book takes an approach based on requirements, ingredients, and applications:

• Requirements: The need to provide services that enable businesses to utilize information is the driving force behind data and information communications technology. The text

PrefaCe xv

outlines the specific requirements that this technology is intended to address. This linkage between requirements and technology is essential to motivate a text of this nature.