Computer Networks and Internets

by Comer, Douglas E.

• ISBN13: 9780133587937
• ISBN10: 0133587932
• Edition: 6th
• Format: Hardcover
• Copyright: 2014-01-02
• Publisher: Pearson

Summary

Appropriate for all introductory-to-intermediate courses in computer networking, the Internet, or Internet applications; readers need no background in networking, operating systems, or advanced mathematics.

 

Leading networking authority Douglas Comer presents a wide-ranging, self-contained tour of the concepts, principles, and technologies that enable today’s Internet to support applications ranging from web browsing to telephony and multimedia. Comer begins by illuminating the applications and facilities offered by today’s Internet. Next, he systematically introduces the underlying network technologies and protocols that make them possible. With these concepts and technologies established, he introduces several of the most important contemporary issues faced by network implementers and managers, including quality of service, Internet telephony, multimedia, network security, and network management. Comer has carefully designed this book to support both top-down and bottom-up teaching approaches. Students need no background in operating systems, and no sophisticated math: Comer relies throughout on figures, drawings, examples, and analogies, not mathematical proofs.

  

Teaching and Learning Experience

This program will provide a better teaching and learning experience—for you and your students.

• Broad Coverage of Key Concepts and Principles, Presented in a Technology-independent Fashion: Comer focuses on imparting knowledge that students will need regardless of which technologies emerge or become obsolete.
• Flexible Organization that Supports both Top-down and Bottom-up Teaching Approaches: Chapters may be sequenced to accommodate a wide variety of course needs and preferences.
• An Accessible Presentation that Resonates with Students: Comer relies throughout on figures, drawings, examples, and analogies, not mathematical proofs.
• Keep Your Course Current: Content is refreshed to provide the most up-to-date information on new technologies for your course.

Author Biography

Dr. Douglas Comer is an internationally recognized expert on TCP/IP protocols, computer networking, and the Internet. One of the researchers who contributed to the Internet as it was being formed in the late 1970s and 1980s, he was a member of the Internet Architecture Board, the group responsible for guiding the Internet's development. He was also chairman of the CSNET technical committee, a member of the CSNET executive committee, and chairman of DARPA's Distributed Systems Architecture Board.

 

Comer has consulted for industry on the design of computer networks. In addition to giving talks in US universities, each year Comer lectures to academics and networking professionals around the world. Comer's operating system, XINU, and implementation of TCP/IP protocols (both documented in his textbooks), have been used in commercial products.

 

Comer is a Distinguished Professor of Computer Science at Purdue University. He is currently on leave from Purdue, serving as VP of Research Collaboration at Cisco Systems. Recently, Comer has taught courses on networking, internetworking, computer architecture, and operating systems. He has developed innovative labs that provide students with the opportunity to gain hands-on experience with operating systems, networks, and protocols. In addition to writing a series of best-selling technical books that have been translated into 16 languages, he served as the North American editor of the journal Software — Practice and Experience for 20 years. Comer is a fellow of the ACM. For additional information, visit his web site.

Table of Contents

Preface xxiii

PART I Introduction And Internet Applications

Chapter 1 Introduction And Overview 1

1.1 Growth Of Computer Networking 1

1.2 Why Networking Seems Complex 2

1.3 The Five Key Aspects Of Networking 2

1.4 Public And Private Parts Of The Internet 6

1.5 Networks, Interoperability, And Standards 8

1.6 Protocol Suites And Layering Models 9

1.7 How Data Passes Through Layers 11

1.8 Headers And Layers 12

1.9 ISO And The OSI Seven Layer Reference Model 13

1.10 Remainder Of The Text 14

1.11 Summary 14

Chapter 2 Internet Trends 17

2.1 Introduction 17

2.2 Resource Sharing 17

2.3 Growth Of The Internet 18

2.4 From Resource Sharing To Communication 21

2.5 From Text To Multimedia 21

2.6 Recent Trends 22

2.7 From Individual Computers To Cloud Computing 23

2.8 Summary 24

Chapter 3 Internet Applications And Network Programming 27

3.1 Introduction 27

3.2 Two Basic Internet Communication Paradigms 28

3.3 Connection-Oriented Communication 29

3.4 The Client-Server Model Of Interaction 30

3.5 Characteristics Of Clients And Servers 31

3.6 Server Programs And Server-Class Computers 31

3.7 Requests, Responses, And Direction Of Data Flow 32

3.8 Multiple Clients And Multiple Servers 32

3.9 Server Identification And Demultiplexing 33

3.10 Concurrent Servers 34

3.11 Circular Dependencies Among Servers 35

3.12 Peer-To-Peer Interactions 35

3.13 Network Programming And The Socket API 36

3.14 Sockets, Descriptors, And Network I/O 36

3.15 Parameters And The Socket API 37

3.16 Socket Calls In A Client And Server 38

3.17 Socket Functions Used By Both Client And Server 38

3.18 The Connect Function Used Only By A Client 40

3.19 Socket Functions Used Only By A Server 40

3.20 Socket Functions Used With The Message Paradigm 43

3.21 Other Socket Functions 44

3.22 Sockets, Threads, And Inheritance 45

3.23 Summary 45

Chapter 4 Traditional Internet Applications 49

4.1 Introduction 49

4.2 Application-Layer Protocols 49

4.3 Representation And Transfer 50

4.4 Web Protocols 51

4.5 Document Representation With HTML 52

4.6 Uniform Resource Locators And Hyperlinks 54

4.7 Web Document Transfer With HTTP 55

4.8 Caching In Browsers 57

4.9 Browser Architecture 59

4.10 File Transfer Protocol (FTP) 59

4.11 FTP Communication Paradigm 60

4.12 Electronic Mail 63

4.13 The Simple Mail Transfer Protocol (SMTP) 64

4.14 ISPs, Mail Servers, And Mail Access 66

4.15 Mail Access Protocols (POP, IMAP) 67

4.16 Email Representation Standards (RFC2822, MIME) 67

4.17 Domain Name System (DNS) 69

4.18 Domain Names That Begin With A Service Name 71

4.19 The DNS Hierarchy And Server Model 72

4.20 Name Resolution 72

4.21 Caching In DNS Servers 74

4.22 Types Of DNS Entries 75

4.23 Aliases And CNAME Resource Records 76

4.24 Abbreviations And The DNS 76

4.25 Internationalized Domain Names 77

4.26 Extensible Representations (XML) 78

4.27 Summary 79

PART II Data Communication Basics

Chapter 5 Overview Of Data Communications 85

5.1 Introduction 85

5.2 The Essence Of Data Communications 86

5.3 Motivation And Scope Of The Subject 87

5.4 The Conceptual Pieces Of A Communications System 87

5.5 The Subtopics Of Data Communications 90

5.6 Summary 91

Chapter 6 Information Sources And Signals 93

6.1 Introduction 93

6.2 Information Sources 93

6.3 Analog And Digital Signals 94

6.4 Periodic And Aperiodic Signals 94

6.5 Sine Waves And Signal Characteristics 95

6.6 Composite Signals 97

6.7 The Importance Of Composite Signals And Sine Functions 97

6.8 Time And Frequency Domain Representations 98

6.9 Bandwidth Of An Analog Signal 99

6.10 Digital Signals And Signal Levels 100

6.11 Baud And Bits Per Second 101

6.12 Converting A Digital Signal To Analog 102

6.13 The Bandwidth Of A Digital Signal 103

6.14 Synchronization And Agreement About Signals 103

6.15 Line Coding 104

6.16 Manchester Encoding Used In Computer Networks 106

6.17 Converting An Analog Signal To Digital 107

6.18 The Nyquist Theorem And Sampling Rate 108

6.19 Nyquist Theorem And Telephone System Transmission 108

6.20 Nonlinear Encoding 109

6.21 Encoding And Data Compression 109

6.22 Summary 110

Chapter 7 Transmission Media 113

7.1 Introduction 113

7.2 Guided And Unguided Transmission 113

7.3 A Taxonomy By Forms Of Energy 114

7.4 Background Radiation And Electrical Noise 115

7.5 Twisted Pair Copper Wiring 115

7.6 Shielding: Coaxial Cable And Shielded Twisted Pair 117

7.7 Categories Of Twisted Pair Cable 118

7.8 Media Using Light Energy And Optical Fibers 119

7.9 Types Of Fiber And Light Transmission 120

7.10 Optical Fiber Compared To Copper Wiring 121

7.11 Infrared Communication Technologies 122

7.12 Point-To-Point Laser Communication 122

7.13 Electromagnetic (Radio) Communication 123

7.14 Signal Propagation 124

7.15 Types Of Satellites 125

7.16 Geostationary Earth Orbit (GEO) Satellites 126

7.17 GEO Coverage Of The Earth 127

7.18 Low Earth Orbit (LEO) Satellites And Clusters 128

7.19 Tradeoffs Among Media Types 128

7.20 Measuring Transmission Media 129

7.21 The Effect Of Noise On Communication 129

7.22 The Significance Of Channel Capacity 130

7.23 Summary 131

Chapter 8 Reliability And Channel Coding 135

8.1 Introduction 135

8.2 The Three Main Sources Of Transmission Errors 135

8.3 Effect Of Transmission Errors On Data 136

8.4 Two Strategies For Handling Channel Errors 137

8.5 Block And Convolutional Error Codes 138

8.6 An Example Block Error Code: Single Parity Checking 139

8.7 The Mathematics Of Block Error Codes And (n,k) Notation 140

8.8 Hamming Distance: A Measure Of A Code’s Strength 140

8.9 The Hamming Distance Among Strings In A Codebook 141

8.10 The Tradeoff Between Error Detection And Overhead 142

8.11 Error Correction With Row And Column (RAC) Parity 142

8.12 The 16-Bit Checksum Used In The Internet 144

8.13 Cyclic Redundancy Codes (CRCs) 145

8.14 An Efficient Hardware Implementation Of CRC 148

8.15 Automatic Repeat Request (ARQ) Mechanisms 148

8.16 Summary 149

Chapter 9 Transmission Modes 153

9.1 Introduction 153

9.2 A Taxonomy Of Transmission Modes 153

9.3 Parallel Transmission 154

9.4 Serial Transmission 155

9.5 Transmission Order: Bits And Bytes 156

9.6 Timing Of Serial Transmission 156

9.7 Asynchronous Transmission 157

9.8 RS-232 Asynchronous Character Transmission 157

9.9 Synchronous Transmission 158

9.10 Bytes, Blocks, And Frames 159

9.11 Isochronous Transmission 160

9.12 Simplex, Half-Duplex, And Full-Duplex Transmission 160

9.13 DCE And DTE Equipment 162

9.14 Summary 162

Chapter 10 Modulation And Modems 165

10.1 Introduction 165

10.2 Carriers, Frequency, And Propagation 165

10.3 Analog Modulation Schemes 166

10.4 Amplitude Modulation 166

10.5 Frequency Modulation 167

10.6 Phase Shift Modulation 168

10.7 Amplitude Modulation And Shannon’s Theorem 168

10.8 Modulation, Digital Input, And Shift Keying 168

10.9 Phase Shift Keying 169

10.10 Phase Shift And A Constellation Diagram 171

10.11 Quadrature Amplitude Modulation 173

10.12 Modem Hardware For Modulation And Demodulation 174

10.13 Optical And Radio Frequency Modems 174

10.14 Dialup Modems 175

10.15 QAM Applied To Dialup 175

10.16 V.32 And V.32bis Dialup Modems 176

10.17 Summary 177

Chapter 11 Multiplexing And Demultiplexing (Channelization) 181

11.1 Introduction 181

11.2 The Concept Of Multiplexing 181

11.3 The Basic Types Of Multiplexing 182

11.4 Frequency Division Multiplexing (FDM) 183

11.5 Using A Range Of Frequencies Per Channel 185

11.6 Hierarchical FDM 186

11.7 Wavelength Division Multiplexing (WDM) 187

11.8 Time Division Multiplexing (TDM) 187

11.9 Synchronous TDM 188

11.10 Framing Used In The Telephone System Version Of TDM 189

11.11 Hierarchical TDM 190

11.12 The Problem With Synchronous TDM: Unfilled Slots 190

11.13 Statistical TDM 191

11.14 Inverse Multiplexing 192

11.15 Code Division Multiplexing 193

11.16 Summary 195

Chapter 12 Access And Interconnection Technologies 199

12.1 Introduction 199

12.2 Internet Access Technology: Upstream And Downstream 199

12.3 Narrowband And Broadband Access Technologies 200

12.4 The Local Loop And ISDN 202

12.5 Digital Subscriber Line (DSL) Technologies 202

12.6 Local Loop Characteristics And Adaptation 203

12.7 The Data Rate Of ADSL 204

12.8 ADSL Installation And Splitters 205

12.9 Cable Modem Technologies 205

12.10 The Data Rate Of Cable Modems 206

12.11 Cable Modem Installation 206

12.12 Hybrid Fiber Coax 207

12.13 Access Technologies That Employ Optical Fiber 208

12.14 Head-End And Tail-End Modem Terminology 208

12.15 Wireless Access Technologies 209

12.16 High-Capacity Connections At The Internet Core 209

12.17 Circuit Termination, DSU/ CSU, And NIU 210

12.18 Telephone Standards For Digital Circuits 211

12.19 DS Terminology And Data Rates 212

12.20 Highest Capacity Circuits (STS Standards) 212

12.21 Optical Carrier Standards 213

12.22 The C Suffix 213

12.23 Synchronous Optical Network (SONET) 214

12.24 Summary 215

PART III Packet Switching And Network Technologies

Chapter 13 Local Area Networks: Packets, Frames, And Topologies 219

13.1 Introduction 219

13.2 Circuit Switching And Analog Communication 220

13.3 Packet Switching 221

13.4 Local And Wide Area Packet Networks 222

13.5 Standards For Packet Format And Identification 223

13.6 IEEE 802 Model And Standards 224

13.7 Point-To-Point And Multi-Access Networks 225

13.8 LAN Topologies 227

13.9 Packet Identification, Demultiplexing, MAC Addresses 229

13.10 Unicast, Broadcast, And Multicast Addresses 230

13.11 Broadcast, Multicast, And Efficient Multi-Point Delivery 231

13.12 Frames And Framing 232

13.13 Byte And Bit Stuffing 233

13.14 Summary 234

Chapter 14 The IEEE MAC Sublayer 239

14.1 Introduction 239

14.2 A Taxonomy Of Mechanisms For Shared Access 239

14.3 Static And Dynamic Channel Allocation 240

14.4 Channelization Protocols 241

14.5 Controlled Access Protocols 242

14.6 Random Access Protocols 244

14.7 Summary 250

Chapter 15 Wired LAN Technology (Ethernet And 802.3) 253

15.1 Introduction 253

15.2 The Venerable Ethernet 253

15.3 Ethernet Frame Format 254

15.4 Ethernet Frame Type Field And Demultiplexing 254

15.5 IEEE’s Version Of Ethernet (802.3) 255

15.6 LAN Connections And Network Interface Cards 256

15.7 Ethernet Evolution And Thicknet Wiring 256

15.8 Thinnet Ethernet Wiring 257

15.9 Twisted Pair Ethernet Wiring And Hubs 258

15.10 Physical And Logical Ethernet Topology 259

15.11 Wiring In An Office Building 259

15.12 Ethernet Data Rates And Cable Types 261

15.13 Twisted Pair Connectors And Cables 261

15.14 Summary 262

Chapter 16 Wireless Networking Technologies 265

16.1 Introduction 265

16.2 A Taxonomy Of Wireless Networks 265

16.3 Personal Area Networks (PANs) 266

16.4 ISM Wireless Bands Used By LANs And PANs 267

16.5 Wireless LAN Technologies And Wi-Fi 267

16.6 Spread Spectrum Techniques 268

16.7 Other Wireless LAN Standards 269

16.8 Wireless LAN Architecture 270

16.9 Overlap, Association, And 802.11 Frame Format 271

16.10 Coordination Among Access Points 272

16.11 Contention And Contention-Free Access 272

16.12 Wireless MAN Technology And WiMax 274

16.13 PAN Technologies And Standards 276

16.14 Other Short-Distance Communication Technologies 277

16.15 Wireless WAN Technologies 278

16.16 Micro Cells 280

16.17 Cell Clusters And Frequency Reuse 280

16.18 Generations Of Cellular Technologies 282

16.19 VSAT Satellite Technology 284

16.20 GPS Satellites 285

16.21 Software Defined Radio And The Future Of Wireless 286

16.22 Summary 287

Chapter 17 Repeaters, Bridges, And Switches 291

17.1 Introduction 291

17.2 Distance Limitation And LAN Design 291

17.3 Fiber Modem Extensions 292

17.4 Repeaters 293

17.5 Bridges And Bridging 293

17.6 Learning Bridges And Frame Filtering 294

17.7 Why Bridging Works Well 295

17.8 Distributed Spanning Tree 296

17.9 Switching And Layer 2 Switches 297

17.10 VLAN Switches 299

17.11 Multiple Switches And Shared VLANs 300

17.12 The Importance Of Bridging 301

17.13 Summary 302

Chapter 18 WAN Technologies And Dynamic Routing 305

18.1 Introduction 305

18.2 Large Spans And Wide Area Networks 305

18.3 Traditional WAN Architecture 306

18.4 Forming A WAN 308

18.5 Store And Forward Paradigm 309

18.6 Addressing In A WAN 309

18.7 Next-Hop Forwarding 310

18.8 Source Independence 313

18.9 Dynamic Routing Updates In A WAN 313

18.10 Default Routes 314

18.11 Forwarding Table Computation 315

18.12 Distributed Route Computation 316

18.13 Shortest Paths And Weights 320

18.14 Routing Problems 321

18.15 Summary 322

Chapter 19 Networking Technologies Past And Present 325

19.1 Introduction 325

19.2 Connection And Access Technologies 325

19.3 LAN Technologies 327

19.4 WAN Technologies 328

19.5 Summary 332

PART IV Internetworking

Chapter 20 Internetworking: Concepts, Architecture, And Protocols 335

20.1 Introduction 335

20.2 The Motivation For Internetworking 335

20.3 The Concept Of Universal Service 336

20.4 Universal Service In A Heterogeneous World 336

20.5 Internetworking 337

20.6 Physical Network Connection With Routers 337

20.7 Internet Architecture 338

20.8 Intranets And Internets 339

20.9 Achieving Universal Service 339

20.10 A Virtual Network 339

20.11 Protocols For Internetworking 341

20.12 Review Of TCP/IP Layering 341

20.13 Host Computers, Routers, And Protocol Layers 342

20.14 Summary 342

Chapter 21 IP: Internet Addressing 345

21.1 Introduction 345

21.2 The Move To IPv6 345

21.3 The Hourglass Model And Difficulty Of Change 346

21.4 Addresses For The Virtual Internet 346

21.5 The IP Addressing Scheme 348

21.6 The IP Address Hierarchy 348

21.7 Original Classes Of IPv4 Addresses 349

21.8 IPv4 Dotted Decimal Notation 350

21.9 Authority For Addresses 351

21.10 IPv4 Subnet And Classless Addressing 351

21.11 Address Masks 353

21.12 CIDR Notation Used With IPv4 354

21.13 A CIDR Example 354

21.14 CIDR Host Addresses 356

21.15 Special IPv4 Addresses 357

21.16 Summary Of Special IPv4 Addresses 359

21.17 IPv4 Berkeley Broadcast Address Form 359

21.18 Routers And The IPv4 Addressing Principle 360

21.19 Multihomed Hosts 361

21.20 IPv6 Multihoming And Network Renumbering 361

21.21 IPv6 Addressing 362

21.22 IPv6 Colon Hexadecimal Notation 363

21.23 Summary 364

Chapter 22 Datagram Forwarding 369

22.1 Introduction 369

22.2 Connectionless Service 369

22.3 Virtual Packets 370

22.4 The IP Datagram 370

22.5 The IPv4 Datagram Header Format 371

22.6 The IPv6 Datagram Header Format 373

22.7 IPv6 Base Header Format 373

22.8 Forwarding An IP Datagram 375

22.9 Network Prefix Extraction And Datagram Forwarding 376

22.10 Longest Prefix Match 377

22.11 Destination Address And Next-Hop Address 378

22.12 Best-Effort Delivery 378

22.13 IP Encapsulation 379

22.14 Transmission Across An Internet 380

22.15 MTU And Datagram Fragmentation 381

22.16 Fragmentation Of An IPv6 Datagram 383

22.17 Reassembly Of An IP Datagram From Fragments 384

22.18 Collecting The Fragments Of A Datagram 385

22.19 The Consequence Of Fragment Loss 386

22.20 Fragmenting An IPv4 Fragment 386

22.21 Summary 387

Chapter 23 Support Protocols And Technologies 391

23.1 Introduction 391

23.2 Address Resolution 391

23.3 An Example Of IPv4 Addresses 393

23.4 The IPv4 Address Resolution Protocol (ARP) 393

23.5 ARP Message Format 394

23.6 ARP Encapsulation 395

23.7 ARP Caching And Message Processing 396

23.8 The Conceptual Address Boundary 398

23.9 Internet Control Message Protocol (ICMP) 399

23.10 ICMP Message Format And Encapsulation 400

23.11 IPv6 Address Binding With Neighbor Discovery 401

23.12 Protocol Software, Parameters, And Configuration 401

23.13 Dynamic Host Configuration Protocol (DHCP) 402

23.14 DHCP Protocol Operation And Optimizations 403

23.15 DHCP Message Format 404

23.16 Indirect DHCP Server Access Through A Relay 405

23.17 IPv6 Autoconfiguration 405

23.18 Network Address Translation (NAT) 406

23.19 NAT Operation And IPv4 Private Addresses 407

23.20 Transport-Layer NAT (NAPT) 409

23.21 NAT And Servers 410

23.22 NAT Software And Systems For Use At Home 410

23.23 Summary 411

Chapter 24 UDP: Datagram Transport Service 415

24.1 Introduction 415

24.2 Transport Protocols And End-To-End Communication 415

24.3 The User Datagram Protocol 416

24.4 The Connectionless Paradigm 417

24.5 Message-Oriented Interface 417

24.6 UDP Communication Semantics 418

24.7 Modes Of Interaction And Multicast Delivery 419

24.8 Endpoint Identification With Protocol Port Numbers 419

24.9 UDP Datagram Format 420

24.10 The UDP Checksum And The Pseudo Header 421

24.11 UDP Encapsulation 421

24.12 Summary 422

Chapter 25 TCP: Reliable Transport Service 425

25.1 Introduction 425

25.2 The Transmission Control Protocol 425

25.3 The Service TCP Provides To Applications 426

25.4 End-To-End Service And Virtual Connections 427

25.5 Techniques That Transport Protocols Use 428

25.6 Techniques To Avoid Congestion 432

25.7 The Art Of Protocol Design 433

25.8 Techniques Used In TCP To Handle Packet Loss 434

25.9 Adaptive Retransmission 435

25.10 Comparison Of Retransmission Times 436

25.11 Buffers, Flow Control, And Windows 437

25.12 TCP’s Three-Way Handshake 438

25.13 TCP Congestion Control 440

25.14 Versions Of TCP Congestion Control 441

25.15 Other Variations: SACK And ECN 441

25.16 TCP Segment Format 442

25.17 Summary 443

Chapter 26 Internet Routing And Routing Protocols 447

26.1 Introduction 447

26.2 Static Vs. Dynamic Routing 447

26.3 Static Routing In Hosts And A Default Route 448

26.4 Dynamic Routing And Routers 449

26.5 Routing In The Global Internet 450

26.6 Autonomous System Concept 451

26.7 The Two Types Of Internet Routing Protocols 451

26.8 Routes And Data Traffic 454

26.9 The Border Gateway Protocol (BGP) 454

26.10 The Routing Information Protocol (RIP) 456

26.11 RIP Packet Format 457

26.12 The Open Shortest Path First Protocol (OSPF) 458

26.13 An Example OSPF Graph 459

26.14 OSPF Areas 459

26.15 Intermediate System - Intermediate System (IS-IS) 460

26.16 Multicast Routing 461

26.17 Summary 465

PART V Other Networking Concepts & Technologies

Chapter 27 Network Performance (QoS And DiffServ) 469

27.1 Introduction 469

27.2 Measures Of Performance 469

27.3 Latency Or Delay 470

27.4 Capacity, Throughput, And Goodput 472

27.5 Understanding Throughput And Delay 473

27.6 Jitter 474

27.7 The Relationship Between Delay And Throughput 475

27.8 Measuring Delay, Throughput, And Jitter 476

27.9 Passive Measurement, Small Packets, And NetFlow 478

27.10 Quality Of Service (QoS) 479

27.11 Fine-Grain And Coarse-Grain QoS 480

27.12 Implementation Of QoS 482

27.13 Internet QoS Technologies 484

27.14 Summary 485

Chapter 28 Multimedia And IP Telephony (VoIP) 489

28.1 Introduction 489

28.2 Real-Time Data Transmission And Best-Effort Delivery 489

28.3 Delayed Playback And Jitter Buffers 490

28.4 Real-Time Transport Protocol (RTP) 491

28.5 RTP Encapsulation 492

28.6 IP Telephony 493

28.7 Signaling And VoIP Signaling Standards 494

28.8 Components Of An IP Telephone System 495

28.9 Summary Of Protocols And Layering 498

28.10 H.323 Characteristics 499

28.11 H.323 Layering 499

28.12 SIP Characteristics And Methods 500

28.13 An Example SIP Session 501

28.14 Telephone Number Mapping And Routing 502

28.15 Summary 503

Chapter 29 Network Security 507

29.1 Introduction 507

29.2 Criminal Exploits And Attacks 507

29.3 Security Policy 511

29.4 Responsibility And Control 512

29.5 Security Technologies 513

29.6 Hashing: An Integrity And Authentication Mechanism 513

29.7 Access Control And Passwords 514

29.8 Encryption: A Fundamental Security Technique 514

29.9 Private Key Encryption 515

29.10 Public Key Encryption 515

29.11 Authentication With Digital Signatures 516

29.12 Key Authorities And Digital Certificates 517

29.13 Firewalls 519

29.14 Firewall Implementation With A Packet Filter 520

29.15 Intrusion Detection Systems 522

29.16 Content Scanning And Deep Packet Inspection 522

29.17 Virtual Private Networks (VPNs) 523

29.18 The Use of VPN Technology For Telecommuting 525

29.19 Packet Encryption Vs. Tunneling 526

29.20 Security Technologies 528

29.21 Summary 529

Chapter 30 Network Management (SNMP) 533

30.1 Introduction 533

30.2 Managing An Intranet 533

30.3 FCAPS: The Industry Standard Model 534

30.4 Example Network Elements 536

30.5 Network Management Tools 536

30.6 Network Management Applications 538

30.7 Simple Network Management Protocol 539

30.8 SNMP’s Fetch-Store Paradigm 539

30.9 The SNMP MIB And Object Names 540

30.10 The Variety Of MIB Variables 541

30.11 MIB Variables That Correspond To Arrays 541

30.12 Summary 542

Chapter 31 Software Defined Networking (SDN) 545

31.1 Introduction 545

31.2 Marketing Hype And Reality 545

31.3 Motivation For A New Approach 546

31.4 Conceptual Organization Of A Network Element 548

31.5 Control Plane Modules And The Hardware Interface 549

31.6 A New Paradigm: Software Defined Networking 550

31.7 Unanswered Questions 551

31.8 Shared Controllers And Network Connections 552

31.9 SDN Communication 553

31.10 OpenFlow: A Controller-To-Element Protocol 554

31.11 Classification Engines In Switches 555

31.12 TCAM And High-Speed Classification 556

31.13 Classification Across Multiple Protocol Layers 557

31.14 TCAM Size And The Need For Multiple Patterns 557

31.15 Items OpenFlow Can Specify 558

31.16 Traditional And Extended IP Forwarding 559

31.17 End-To-End Path With MPLS Using Layer 2 560

31.18 Dynamic Rule Creation And Control Of Flows 561

31.19 A Pipeline Model For Flow Tables 562

31.20 SDN’s Potential Effect On Network Vendors 563

31.21 Summary 564

Chapter 32 The Internet Of Things 567

32.1 Introduction 567

32.2 Embedded Systems 567

32.3 Choosing A Network Technology 569

32.4 Energy Harvesting 570

32.5 Low Power Wireless Communication 570

32.6 Mesh Topology 571

32.7 The ZigBee Alliance 571

32.8 802.15.4 Radios And Wireless Mesh Networks 572

32.9 Internet Connectivity And Mesh Routing 573

32.10 IPv6 In A ZigBee Mesh Network 574

32.11 The ZigBee Forwarding Paradigm 575

32.12 Other Protocols In the ZigBee Stack 576

32.13 Summary 577

Chapter 33 Trends In Networking Technologies And Uses 579

33.1 Introduction 579

33.2 The Need For Scalable Internet Services 579

33.3 Content Caching (Akamai) 580

33.4 Web Load Balancers 580

33.5 Server Virtualization 581

33.6 Peer-To-Peer Communication 581

33.7 Distributed Data Centers And Replication 582

33.8 Universal Representation (XML) 582

33.9 Social Networking 583

33.10 Mobility And Wireless Networking 583

33.11 Digital Video 583

33.12 Higher-Speed Access And Switching 584

33.13 Cloud Computing 584

33.14 Overlay Networks 584

33.15 Middleware 586

33.16 Widespread Deployment Of IPv6 586

33.17 Summary 587

Appendix 1 A Simplified Application Programming Interface 589

Index 617