Computer Networks and Internets is 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. This Fifth Edition has been thoroughly reorganized, revised, and updated: it includes extensive new coverage of topics ranging from wireless protocols to network performance, while reducing or eliminating coverage of older protocols and technologies. 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: low-level data communications; packet switching, LAN, and WAN technologies; and Internet protocols such as TCP, IP, UDP, and IPv6. 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.
Author(s): Douglas E Comer
Edition: 5th
Publisher: Prentice Hall
Year: 2008
Language: English
Pages: 637
Cover ......Page 1
Title Page......Page 4
Copyright......Page 5
Contents......Page 8
Preface......Page 24
PART I: Introduction And Internet Applications......Page 34
1.1 Growth Of Computer Networking......Page 36
1.3 The Five Key Aspects Of Networking......Page 37
1.4 Public And Private Parts Of The Internet......Page 41
1.5 Networks, Interoperability, And Standards......Page 43
1.6 Protocol Suites And Layering Models......Page 44
1.7 How Data Passes Through Layers......Page 46
1.8 Headers And Layers......Page 47
1.10 The Inside Scoop......Page 48
1.11 Remainder Of The Text......Page 49
1.12 Summary......Page 50
2.2 Resource Sharing......Page 52
2.3 Growth Of The Internet......Page 53
2.5 From Text To Multimedia......Page 56
2.6 Recent Trends......Page 57
2.7 Summary......Page 58
3.1 Introduction......Page 62
3.2 Two Basic Internet Communication Paradigms......Page 63
3.3 Connection-oriented Communication......Page 64
3.4 The Client-Server Model Of Interaction......Page 65
3.6 Server Programs And Server-Class Computers......Page 66
3.8 Multiple Clients And Multiple Servers......Page 67
3.9 Server Identification And Demultiplexing......Page 68
3.10 Concurrent Servers......Page 69
3.12 Peer-To-Peer Interactions......Page 70
3.14 Sockets, Descriptors, And Network I/O......Page 71
3.15 Parameters And The Socket API......Page 72
3.17 Socket Functions Used By Both Client And Server......Page 73
3.19 Socket Functions Used Only By A Server......Page 75
3.20 Socket Functions Used With The Message Paradigm......Page 78
3.21 Other Socket Functions......Page 79
3.23 Summary......Page 80
4.2 Application-Layer Protocols......Page 84
4.3 Representation And Transfer......Page 85
4.4 Web Protocols......Page 86
4.5 Document Representation With HTML......Page 87
4.6 Uniform Resource Locators And Hyperlinks......Page 89
4.7 Web Document Transfer With HTTP......Page 90
4.8 Caching In Browsers......Page 92
4.10 File Transfer Protocol (FTP)......Page 94
4.11 FTP Communication Paradigm......Page 95
4.12 Electronic Mail......Page 98
4.13 The Simple Mail Transfer Protocol (SMTP)......Page 99
4.14 ISPs, Mail Servers, And Mail Access......Page 101
4.16 Email Representation Standards (RFC2822, MIME)......Page 102
4.17 Domain Name System (DNS)......Page 104
4.18 Domain Names That Begin With www......Page 106
4.20 Name Resolution......Page 107
4.21 Caching In DNS Servers......Page 109
4.22 Types Of DNS Entries......Page 110
4.24 Abbreviations And The DNS......Page 111
4.25 Internationalized Domain Names......Page 112
4.26 Extensible Representations (XML)......Page 113
4.27 Summary......Page 114
PART II: Data Communication Basics......Page 118
5.1 Introduction......Page 120
5.2 The Essence Of Data Communications......Page 121
5.4 The Conceptual Pieces Of A Communication System......Page 122
5.5 The Subtopics Of Data Communications......Page 125
5.6 Summary......Page 126
6.2 Information Sources......Page 128
6.4 Periodic And Aperiodic Signals......Page 129
6.5 Sine Waves And Signal Characteristics......Page 130
6.7 The Importance Of Composite Signals And Sine Functions......Page 132
6.8 Time And Frequency Domain Representations......Page 133
6.9 Bandwidth Of An Analog Signal......Page 134
6.10 Digital Signals And Signal Levels......Page 135
6.11 Baud And Bits Per Second......Page 136
6.12 Converting A Digital Signal To Analog......Page 137
6.14 Synchronization And Agreement About Signals......Page 138
6.15 Line Coding......Page 139
6.16 Manchester Encoding Used In Computer Networks......Page 141
6.17 Converting An Analog Signal To Digital......Page 142
6.19 Nyquist Theorem And Telephone System Transmission......Page 143
6.20 Encoding And Data Compression......Page 144
6.21 Summary......Page 145
7.2 Guided And Unguided Transmission......Page 148
7.3 A Taxonomy By Forms Of Energy......Page 149
7.5 Twisted Pair Copper Wiring......Page 150
7.6 Shielding: Coaxial Cable And Shielded Twisted Pair......Page 152
7.7 Categories Of Twisted Pair Cable......Page 153
7.8 Media Using Light Energy And Optical Fibers......Page 154
7.9 Types Of Fiber And Light Transmission......Page 155
7.10 Optical Fiber Compared To Copper Wiring......Page 156
7.12 Point-To-Point Laser Communication......Page 157
7.13 Electromagnetic (Radio) Communication......Page 158
7.14 Signal Propagation......Page 159
7.15 Types Of Satellites......Page 160
7.16 GEO Communication Satellites......Page 161
7.17 GEO Coverage Of The Earth......Page 162
7.19 Tradeoffs Among Media Types......Page 163
7.21 The Effect Of Noise On Communication......Page 164
7.22 The Significance Of Channel Capacity......Page 165
7.23 Summary......Page 166
8.2 The Three Main Sources Of Transmission Errors......Page 170
8.3 Effect Of Transmission Errors On Data......Page 171
8.4 Two Strategies For Handling Channel Errors......Page 172
8.5 Block And Convolutional Error Codes......Page 173
8.6 An Example Block Error Code: Single Parity Checking......Page 174
8.8 Hamming Distance: A Measure Of A Code’s Strength......Page 175
8.9 The Hamming Distance Among Strings In A Codebook......Page 176
8.11 Error Correction With Row And Column (RAC) Parity......Page 177
8.12 The 16-Bit Checksum Used In The Internet......Page 179
8.13 Cyclic Redundancy Codes (CRCs)......Page 180
8.15 Automatic Repeat reQuest (ARQ) Mechanisms......Page 183
8.16 Summary......Page 184
9.2 A Taxonomy Of Transmission Modes......Page 188
9.3 Parallel Transmission......Page 189
9.4 Serial Transmission......Page 190
9.6 Timing Of Serial Transmission......Page 191
9.8 RS-232 Asynchronous Character Transmission......Page 192
9.9 Synchronous Transmission......Page 193
9.10 Bytes, Blocks, And Frames......Page 194
9.12 Simplex, Half-Duplex, and Full-Duplex Transmission......Page 195
9.14 Summary......Page 197
10.2 Carriers, Frequency, And Propagation......Page 200
10.4 Amplitude Modulation......Page 201
10.5 Frequency Modulation......Page 202
10.7 Amplitude Modulation And Shannon’s Theorem......Page 203
10.9 Phase Shift Keying......Page 204
10.10 Phase Shift And A Constellation Diagram......Page 206
10.11 Quadrature Amplitude Modulation......Page 208
10.13 Optical And Radio Frequency Modems......Page 209
10.15 QAM Applied To Dialup......Page 210
10.16 V.32 and V.32bis Dialup Modems......Page 211
10.17 Summary......Page 212
11.2 The Concept Of Multiplexing......Page 216
11.3 The Basic Types Of Multiplexing......Page 217
11.4 Frequency Division Multiplexing (FDM)......Page 218
11.5 Using A Range Of Frequencies Per Channel......Page 220
11.6 Hierarchical FDM......Page 221
11.8 Time Division Multiplexing (TDM)......Page 222
11.9 Synchronous TDM......Page 223
11.10 Framing Used In The Telephone System Version Of TDM......Page 224
11.12 The Problem With Synchronous TDM: Unfilled Slots......Page 225
11.13 Statistical TDM......Page 226
11.14 Inverse Multiplexing......Page 227
11.15 Code Division Multiplexing......Page 228
11.16 Summary......Page 230
12.2 Internet Access Technology: Upstream And Downstream......Page 234
12.3 Narrowband And Broadband Access Technologies......Page 235
12.5 Digital Subscriber Line (DSL) Technologies......Page 237
12.6 Local Loop Characteristics And Adaptation......Page 238
12.7 The Data Rate Of ADSL......Page 239
12.9 Cable Modem Technologies......Page 240
12.11 Cable Modem Installation......Page 241
12.12 Hybrid Fiber Coax......Page 242
12.14 Head-End And Tail-End Modem Terminology......Page 243
12.16 High-Capacity Connections At The Internet Core......Page 244
12.17 Circuit Termination, DSU/ CSU, and NIU......Page 245
12.18 Telephone Standards For Digital Circuits......Page 246
12.19 DS Terminology And Data Rates......Page 247
12.22 The C Suffix......Page 248
12.23 Synchronous Optical NETwork (SONET)......Page 249
12.24 Summary......Page 250
PART III: Packet Switching And Network Technologies......Page 254
13.1 Introduction......Page 256
13.2 Circuit Switching......Page 257
13.3 Packet Switching......Page 258
13.4 Local And Wide Area Packet Networks......Page 259
13.5 Standards For Packet Format And Identification......Page 260
13.6 IEEE 802 Model And Standards......Page 261
13.8 LAN Topologies......Page 264
13.9 Packet Identification, Demultiplexing, MAC Addresses......Page 266
13.10 Unicast, Broadcast, And Multicast Addresses......Page 267
13.11 Broadcast, Multicast, And Efficient Multi-Point Delivery......Page 268
13.12 Frames And Framing......Page 269
13.13 Byte And Bit Stuffing......Page 270
13.14 Summary......Page 272
14.2 A Taxonomy Of Mechanisms For Multi-Access......Page 276
14.3 Static And Dynamic Channel Allocation......Page 277
14.4 Channelization Protocols......Page 278
14.5 Controlled Access Protocols......Page 279
14.6 Random Access Protocols......Page 281
14.7 Summary......Page 287
15.2 The Venerable Ethernet......Page 290
15.4 Ethernet Type Field And Demultiplexing......Page 291
15.5 IEEE’s Version Of Ethernet (802.3)......Page 292
15.7 Ethernet Evolution And Thicknet Wiring......Page 293
15.8 Thinnet Ethernet Wiring......Page 294
15.9 Twisted Pair Ethernet Wiring And Hubs......Page 295
15.11 Wiring In An Office Building......Page 296
15.13 Twisted Pair Connectors And Cables......Page 298
15.14 Summary......Page 299
16.2 A Taxonomy Of Wireless Networks......Page 302
16.3 Personal Area Networks (PANs)......Page 303
16.5 Wireless LAN Technologies And Wi-Fi......Page 304
16.6 Spread Spectrum Techniques......Page 305
16.7 Other Wireless LAN Standards......Page 306
16.8 Wireless LAN Architecture......Page 307
16.9 Overlap, Association, And 802.11 Frame Format......Page 308
16.11 Contention And Contention-Free Access......Page 309
16.12 Wireless MAN Technology and WiMax......Page 311
16.13 PAN Technologies And Standards......Page 313
16.14 Other Short-Distance Communication Technologies......Page 314
16.15 Wireless WAN Technologies......Page 315
16.16 Cell Clusters And Frequency Reuse......Page 317
16.17 Generations Of Cellular Technologies......Page 318
16.18 VSAT Satellite Technology......Page 321
16.19 GPS Satellites......Page 322
16.20 Software Radio And The Future Of Wireless......Page 323
16.21 Summary......Page 324
17.2 Distance Limitation And LAN Design......Page 328
17.3 Fiber Modem Extensions......Page 329
17.5 Bridges And Bridging......Page 330
17.6 Learning Bridges And Frame Filtering......Page 331
17.7 Why Bridging Works Well......Page 332
17.8 Distributed Spanning Tree......Page 333
17.9 Switching And Layer 2 Switches......Page 334
17.10 VLAN Switches......Page 336
17.12 Summary......Page 337
18.2 Large Spans And Wide Area Networks......Page 340
18.3 Traditional WAN Architecture......Page 341
18.4 Forming A WAN......Page 343
18.6 Addressing In A WAN......Page 344
18.7 Next-Hop Forwarding......Page 345
18.9 Dynamic Routing Updates In A WAN......Page 348
18.10 Default Routes......Page 349
18.11 Forwarding Table Computation......Page 350
18.12 Distributed Route Computation......Page 351
18.13 Shortest Path Computation In A Graph......Page 355
18.14 Routing Problems......Page 356
18.15 Summary......Page 357
19.2 Connection And Access Technologies......Page 360
19.3 LAN Technologies......Page 362
19.4 WAN Technologies......Page 363
19.5 Summary......Page 366
PART IV: Internetworking......Page 368
20.2 The Motivation For Internetworking......Page 370
20.4 Universal Service In A Heterogeneous World......Page 371
20.6 Physical Network Connection With Routers......Page 372
20.7 Internet Architecture......Page 373
20.9 A Virtual Network......Page 374
20.11 Review Of TCP/IP Layering......Page 376
20.13 Summary......Page 377
21.2 Addresses For The Virtual Internet......Page 380
21.4 The IP Address Hierarchy......Page 381
21.5 Original Classes Of IP Addresses......Page 382
21.6 Dotted Decimal Notation......Page 383
21.7 Division Of The Address Space......Page 384
21.9 Subnet And Classless Addressing......Page 385
21.10 Address Masks......Page 387
21.12 A CIDR Example......Page 388
21.13 CIDR Host Addresses......Page 390
21.14 Special IP Addresses......Page 391
21.16 The Berkeley Broadcast Address Form......Page 393
21.17 Routers And The IP Addressing Principle......Page 394
21.19 Summary......Page 395
22.2 Connectionless Service......Page 398
22.4 The IP Datagram......Page 399
22.5 The IP Datagram Header Format......Page 400
22.6 Forwarding An IP Datagram......Page 402
22.7 Network Prefix Extraction And Datagram Forwarding......Page 403
22.9 Destination Address And Next-Hop Address......Page 404
22.11 IP Encapsulation......Page 405
22.12 Transmission Across An Internet......Page 406
22.13 MTU And Datagram Fragmentation......Page 408
22.14 Reassembly Of A Datagram From Fragments......Page 409
22.15 Collecting The Fragments Of A Datagram......Page 410
22.17 Fragmenting A Fragment......Page 411
22.18 Summary......Page 412
23.2 Address Resolution......Page 416
23.3 The Address Resolution Protocol (ARP)......Page 418
23.4 ARP Message Format......Page 419
23.5 ARP Encapsulation......Page 420
23.6 ARP Caching And Message Processing......Page 421
23.7 The Conceptual Address Boundary......Page 423
23.8 Internet Control Message Protocol (ICMP)......Page 424
23.10 Protocol Software, Parameters, And Configuration......Page 426
23.11 Dynamic Host Configuration Protocol (DHCP)......Page 427
23.13 DHCP Message Format......Page 429
23.14 Indirect DHCP Server Access Through A Relay......Page 430
23.15 Network Address Translation (NAT)......Page 431
23.16 NAT Operation And Private Addresses......Page 432
23.17 Transport-Layer NAT (NAPT)......Page 434
23.19 NAT Software And Systems For Use At Home......Page 435
23.20 Summary......Page 436
24.2 The Success Of IP......Page 440
24.3 The Motivation For Change......Page 441
24.4 The Hourglass Model And Difficulty Of Change......Page 442
24.6 IPv6 Features......Page 443
24.7 IPv6 Datagram Format......Page 444
24.8 IPv6 Base Header Format......Page 445
24.9 Implicit And Explicit Header Size......Page 446
24.10 Fragmentation, Reassembly, And Path MTU......Page 447
24.11 The Purpose Of Multiple Headers......Page 448
24.12 IPv6 Addressing......Page 449
24.13 IPv6 Colon Hexadecimal Notation......Page 450
24.14 Summary......Page 451
25.2 Transport Protocols And End-To-End Communication......Page 454
25.3 The User Datagram Protocol......Page 455
25.5 Message-Oriented Interface......Page 456
25.6 UDP Communication Semantics......Page 457
25.7 Modes Of Interaction And Broadcast Delivery......Page 458
25.9 UDP Datagram Format......Page 459
25.10 The UDP Checksum And The Pseudo Header......Page 460
25.12 Summary......Page 461
26.2 The Transmission Control Protocol......Page 464
26.3 The Service TCP Provides To Applications......Page 465
26.4 End-To-End Service And Virtual Connections......Page 466
26.5 Techniques That Transport Protocols Use......Page 467
26.6 Techniques To Avoid Congestion......Page 471
26.7 The Art Of Protocol Design......Page 472
26.8 Techniques Used In TCP To Handle Packet Loss......Page 473
26.9 Adaptive Retransmission......Page 474
26.10 Comparison Of Retransmission Times......Page 475
26.11 Buffers, Flow Control, And Windows......Page 476
26.12 TCP’s Three-Way Handshake......Page 477
26.13 TCP Congestion Control......Page 478
26.14 TCP Segment Format......Page 479
26.15 Summary......Page 481
27.2 Static Vs. Dynamic Routing......Page 484
27.3 Static Routing In Hosts And A Default Route......Page 485
27.4 Dynamic Routing And Routers......Page 486
27.5 Routing In The Global Internet......Page 487
27.7 The Two Types Of Internet Routing Protocols......Page 488
27.9 The Border Gateway Protocol (BGP)......Page 491
27.10 The Routing Information Protocol (RIP)......Page 493
27.11 RIP Packet Format......Page 494
27.12 The Open Shortest Path First Protocol (OSPF)......Page 495
27.14 OSPF Areas......Page 496
27.15 Intermediate System - Intermediate System (IS-IS)......Page 497
27.16 Multicast Routing......Page 498
27.17 Summary......Page 502
PART V: Other Networking Concepts & Technologies......Page 504
28.2 Measures Of Performance......Page 506
28.3 Latency Or Delay......Page 507
28.4 Throughput, Capacity, And Goodput......Page 509
28.5 Understanding Throughput And Delay......Page 510
28.6 Jitter......Page 511
28.7 The Relationship Between Delay And Throughput......Page 512
28.8 Measuring Delay, Throughput, And Jitter......Page 513
28.9 Passive Measurement, Small Packets, And NetFlow......Page 515
28.10 Quality Of Service (QoS)......Page 516
28.11 Fine-Grain And Coarse-Grain QoS......Page 517
28.12 Implementation Of QoS......Page 519
28.13 Internet QoS Technologies......Page 521
28.14 Summary......Page 522
29.2 Real-Time Data Transmission And Best Effort Delivery......Page 526
29.3 Delayed Playback And Jitter Buffers......Page 527
29.4 Real-time Transport Protocol (RTP)......Page 528
29.5 RTP Encapsulation......Page 529
29.6 IP Telephony......Page 530
29.7 Signaling And VoIP Signaling Standards......Page 531
29.8 Components Of An IP Telephone System......Page 532
29.9 Summary Of Protocols And Layering......Page 535
29.11 H.323 Layering......Page 536
29.12 SIP Characteristics And Methods......Page 537
29.13 An Example SIP Session......Page 538
29.14 Telephone Number Mapping And Routing......Page 539
29.15 Summary......Page 540
30.2 Criminal Exploits And Attacks......Page 544
30.3 Security Policy......Page 548
30.4 Responsibility And Control......Page 549
30.6 Hashing: An Integrity And Authentication Mechanism......Page 550
30.8 Encryption: A Fundamental Security Technique......Page 551
30.10 Public Key Encryption......Page 552
30.11 Authentication With Digital Signatures......Page 553
30.12 Key Authorities And Digital Certificates......Page 554
30.13 Firewalls......Page 556
30.14 Firewall Implementation With A Packet Filter......Page 557
30.16 Content Scanning And Deep Packet Inspection......Page 559
30.17 Virtual Private Networks (VPNs)......Page 560
30.18 The Use of VPN Technology For Telecommuting......Page 562
30.19 Packet Encryption Vs. Tunneling......Page 563
30.20 Security Technologies......Page 565
30.21 Summary......Page 566
31.2 Managing An Intranet......Page 570
31.3 FCAPS: The Industry Standard Model......Page 571
31.4 Example Network Elements......Page 573
31.5 Network Management Tools......Page 574
31.6 Network Management Applications......Page 575
31.7 Simple Network Management Protocol......Page 576
31.9 The SNMP MIB And Object Names......Page 577
31.11 MIB Variables That Correspond To Arrays......Page 578
31.12 Summary......Page 579
32.2 The Need For Scalable Internet Services......Page 582
32.4 Web Load Balancers......Page 583
32.6 Peer-To-Peer Communication......Page 584
32.8 Universal Representation (XML)......Page 585
32.11 Digital Video......Page 586
32.14 Optical Switching......Page 587
32.17 Ad Hoc Networks......Page 588
32.20 Summary......Page 589
Appendix 1 A Simplified Application Programming Interface......Page 592
A......Page 620
B......Page 621
C......Page 622
D......Page 623
E......Page 624
G......Page 625
I......Page 626
L......Page 627
M......Page 628
O......Page 629
P......Page 630
R......Page 631
S......Page 632
T......Page 633
U......Page 634
Z......Page 635
