USES OF COMPUTER NETWORKS
1.1.1 Access to Information 2
1.1.2 Person-to-Person Communication 5
1.1.3 Electronic Commerce 6
1.1.4 Entertainment 6
1.1.5 The Internet of Things 7
1.2
TYPES OF COMPUTER NETWORKS 7
1.2.1 Broadband Access Networks 8
1.2.2 Mobile and Wireless Access Networks1.2.3 Content Provider Networks 11
1.2.4 Transit Networks 12
1.2.5 Enterprise Networks 13
8
1.3
NETWORK TECHNOLOGY, FROM LOCAL TO GLOBAL1.3.1 Personal Area Networks 15
1.3.2 Local Area Networks 16
1.3.3 Home Networks 18
1.3.4 Metropolitan Area Networks 20
1.3.5 Wide Area Networks 21
1.3.6 Internetworks 25
EXAMPLES OF NETWORKS 26
1.4.1 The Internet 26
1.4.2 Mobile Networks 36
1.4.3 Wireless Networks (WiFi) 43
1.5
NETWORK PROTOCOLS 47
1.5.1 Design Goals 47
1.5.2 Protocol Layering 49
1.5.3 Connections and Reliability 53
1.5.4 Service Primitives 56
1.5.5 The Relationship of Services to Protocols 58
1.6
REFERENCE MODELS 59
1.6.1 The OSI Reference Model 59
1.6.2 The TCP/IP Reference Model 61
1.6.3 A Critique of the OSI Model and Protocols 64
1.6.4 A Critique of the TCP/IP Reference Model and Protocols1.6.5 The Model Used in This Book 67
66
1.7
STANDARDIZATION 68
1.7.1 Standardization and Open Source 68
1.7.2 Who’s Who in the Telecommunications World 69
1.7.3 Who’s Who in the International Standards World 71
1.7.4 Who’s Who in the Internet Standards World 72
1.8
POLICY, LEGAL, AND SOCIAL ISSUES 75
1.8.1 Online Speech 75
1.8.2 Net Neutrality 76
1.8.3 Security 77
1.8.4 Privacy 78
1.8.5 Disinformation 79
2 THE PHYSICAL LAYER
GUIDED TRANSMISSION MEDIA 90
2.1.1 Persistent Storage 90
2.1.2 Twisted Pairs 91
2.1.3 Coaxial Cable 93
2.1.4 Power Lines 94
2.1.5 Fiber Optics 95
2.2
WIRELESS TRANSMISSION 100
2.2.1 The Electromagnetic Spectrum 101
2.2.2 Frequency Hopping Spread Spectrum 103
2.2.3 Direct Sequence Spread Spectrum 103
2.2.4 Ultra-Wideband Communication 104
2.3
USING THE SPECTRUM FOR TRANSMISSION 104
2.3.1 Radio Transmission 104
2.3.2 Microwave Transmission 106
2.3.3 Infrared Transmission 107
2.3.4 Light Transmission 108
2.4
FROM WAVEFORMS TO BITS 109
2.4.1 The Theoretical Basis for Data Communication2.4.2 The Maximum Data Rate of a Channel 114
2.4.3 Digital Modulation 115
2.4.4 Multiplexing 123
110
2.5
THE PUBLIC SWITCHED TELEPHONE NETWORK 131
2.5.1 Structure of the Telephone System 131
2.5.2 The Local Loop: Telephone Modems, ADSL, and Fiber2.5.3 Trunks and Multiplexing 143
2.5.4 Switching 149
134
2.6
CELLULAR NETWORKS 154
2.6.1 Common Concepts: Cells, Handoff, Paging 155
2.6.2 First-Generation (1G) Technology: Analog Voice 156
2.6.3 Second-Generation (2G) Technology: Digital Voice 158
2.6.4 GSM: The Global System for Mobile Communications 159
2.6.5 Third-Generation (3G) Technology: Digital Voice and Data 162
2.6.6 Fourth-Generation (4G) Technology: Packet Switching 166
2.6.7 Fifth-Generation (5G) Technology 168
2.7
CABLE NETWORKS 169
2.7.1 A History of Cable Networks: Community Antenna Television 170
2.7.2 Broadband Internet Access Over Cable: HFC Networks 170
2.7.3 DOCSIS 173
2.7.4 Resource Sharing in DOCSIS Networks: Nodes and Minislots 174
2.8
COMMUNICATION SATELLITES 176
2.8.1 Geostationary Satellites 177
2.8.2 Medium-Earth Orbit Satellites 181
2.8.3 Low-Earth Orbit Satellites 181
2.9
COMPARING DIFFERENT ACCESS NETWORKS 184
2.9.1 Terrestrial Access Networks: Cable, Fiber, and ADSL2.9.2 Satellites Versus Terrestrial Networks 186
184
2.10POLICY AT THE PHYSICAL LAYER2.10.1 Spectrum Allocation 187
2.10.2 The Cellular Network 190
2.10.3 The Telephone Network 192
187
2.11 SUMMARY 194
3 THE DATA LINK LAYER
3.1
DAT A LINK LAYER DESIGN ISSUES 202
3.1.1 Services Provided to the Network Layer3.1.2 Framing 205
3.1.3 Error Control 208
3.1.4 Flow Control 209
203
3.2
ERROR DETECTION AND CORRECTION 210
3.2.1 Error-Correcting Codes 212
3.2.2 Error-Detecting Codes 217
3.3
ELEMENTARY DAT A LINK PROTOCOLS3.3.1 Initial Simplifying Assumptions 223
3.3.2 Basic Transmission and Receipt 224
3.3.3 Simplex Link-Layer Protocols 228
223
3.4
3.5
IMPROVING EFFICIENCY 234
3.4.1 Goal: Bidirectional Transmission, Multiple Frames in Flight3.4.2 Examples of Full-Duplex, Sliding Window Protocols 238
234
DAT A LINK PROTOCOLS IN PRACTICE 252
3.5.1 Packet over SONET 253
3.5.2 ADSL (Asymmetric Digital Subscriber Loop) 256
3.5.3 Data Over Cable Service Interface Specification (DOCSIS)259
3.6
SUMMARY 261
4 THE MEDIUM ACCESS CONTROL SUBLAYER 267
4.1
THE CHANNEL ALLOCATION PROBLEM 268
4.1.1 Static Channel Allocation 268
4.1.2 Assumptions for Dynamic Channel Allocation270
4.2
MULTIPLE ACCESS PROTOCOLS 271
4.2.1 ALOHA 272
4.2.2 Carrier Sense Multiple Access Protocols4.2.3 Collision-Free Protocols 279
4.2.4 Limited-Contention Protocols 283
4.2.5 Wireless LAN Protocols 287
276
4.3
ETHERNET 290
4.3.1 Classic Ethernet Physical Layer 290
4.3.2 Classic Ethernet MAC Sublayer Protocol 292
4.3.3 Ethernet Performance 296
4.3.4 Switched Ethernet 297
4.3.5 Fast Ethernet 300
4.3.6 Gigabit Ethernet 302
4.3.7 10-Gigabit Ethernet 306
4.3.8 40- and 100-Gigabit Ethernet 307
4.3.9 Retrospective on Ethernet 308
4.4
WIRELESS LANS 309
4.4.1 The 802.11 Architecture and Protocol Stack4.4.2 The 802.11 Physical Layer 311
310
4.4.3 The 802.11 MAC Sublayer Protocol4.4.4 The 802.11 Frame Structure 321
4.4.5 Services 322
314
BLUETOOTH 324
4.5.1 Bluetooth Architecture 325
4.5.2 Bluetooth Applications 326
4.5.3 The Bluetooth Protocol Stack 327
4.5.4 The Bluetooth Radio Layer 328
4.5.5 The Bluetooth Link Layers 329
4.5.6 The Bluetooth Frame Structure 330
4.5.7 Bluetooth 5 331
4.6
DOCSIS 332
4.6.1 Overview 332
4.6.2 Ranging 333
4.6.3 Channel Bandwidth Allocation 333
4.7
DAT A LINK LAYER SWITCHING 334
4.7.1 Uses of Bridges 335
4.7.2 Learning Bridges 336
4.7.3 Spanning-Tree Bridges 339
4.7.4 Repeaters, Hubs, Bridges, Switches, Routers, and Gateways4.7.5 Virtual LANs 345
342
4.8
SUMMARY 351
5 THE NETWORK LAYER
359
5.1
NETWORK LAYER DESIGN ISSUES 360
5.1.1 Store-and-Forward Packet Switching 360
5.1.2 Services Provided to the Transport Layer 361
5.1.3 Implementation of Connectionless Service 362
5.1.4 Implementation of Connection-Oriented Service 363
5.1.5 Comparison of Virtual-Circuit and Datagram Networks365
5.2
ROUTING ALGORITHMS IN A SINGLE NETWORK5.2.1 The Optimality Principle 368
5.2.2 Shortest Path Algorithm 370
5.2.3
Flooding 372
5.2.4
Distance Vector Routing 374
5.2.5
Link State Routing 377
5.2.6
Hierarchical Routing within a Network 382
5.2.7
Broadcast Routing 384
5.2.8
Multicast Routing 386
5.2.9
Anycast Routing 389
5.3
TRAFFIC MANAGEMENT AT THE NETWORK LAYER5.3.1 The Need for Traffic Management: Congestion 390
5.3.2 Approaches to Traffic Management 393
390
5.4
QUALITY OF SERVICE AND APPLICATION QOE 406
5.4.1 Application QoS Requirements 406
5.4.2 Overprovisioning 409
5.4.3 Packet Scheduling 410
5.4.4 Integrated Services 417
5.4.5 Differentiated Services 420
5.5
INTERNETWORKING 423
5.5.1 Internetworks: An Overview 423
5.5.2 How Networks Differ 424
5.5.3 Connecting Heterogeneous Networks 425
5.5.4 Connecting Endpoints Across Heterogeneous Networks 428
5.5.5 Internetwork Routing: Routing Across Multiple Networks 430
5.5.6 Supporting Different Packet Sizes: Packet Fragmentation 431
5.6
SOFTWARE-DEFINED NETWORKING 435
5.6.1 Overview 435
5.6.2 The SDN Control Plane: Logically Centralized Software Control5.6.3 The SDN Data Plane: Programmable Hardware 438
5.6.4 Programmable Network Telemetry 440
436
5.7
THE NETWORK LAYER IN THE INTERNET 441
5.7.1 The IP Version 4 Protocol 444
5.7.2 IP Addresses 448
5.7.3 IP Version 6 461
5.7.4 Internet Control Protocols 470
5.7.5 Label Switching and MPLS 476
5.7.6 OSPF—An Interior Gateway Routing Protocol 479
5.7.7 BGP—The Exterior Gateway Routing Protocol 484
5.7.8 Internet Multicasting 491
POLICY AT THE NETWORK LAYER5.8.1 Peering Disputes 492
5.8.2 Traffic Prioritization 493
SUMMARY 494
492
6 THE TRANSPORT LAYER
6.1
THE TRANSPORT SERVICE 501
6.1.1 Services Provided to the Upper Layers 502
6.1.2 Transport Service Primitives 504
6.1.3 Berkeley Sockets 506
6.1.4 An Example of Socket Programming: An Internet File Server6.2
ELEMENTS OF TRANSPORT PROTOCOLS 513
6.2.1 Addressing 514
6.2.2 Connection Establishment 517
6.2.3 Connection Release 523
6.2.4 Error Control and Flow Control 528
6.2.5 Multiplexing 533
6.2.6 Crash Recovery 533
6.3
CONGESTION CONTROL 536
6.3.1 Desirable Bandwidth Allocation 536
6.3.2 Regulating the Sending Rate 540
6.3.3 Wireless Issues 544
6.4
6.5
THE INTERNET TRANSPORT PROTOCOLS: UDP 546
6.4.1 Introduction to UDP 547
6.4.2 Remote Procedure Call 549
6.4.3 Real-Time Transport Protocols 552
THE INTERNET TRANSPORT PROTOCOLS: TCP6.5.1 Introduction to TCP 558
6.5.2 The TCP Service Model 558
6.5.3 The TCP Protocol 561
6.5.4 The TCP Segment Header 562
6.5.5 TCP Connection Establishment 565
6.5.6 TCP Connection Release 567
5
6.5.7 TCP Connection Management Modeling 567
6.5.8 TCP Sliding Window 570
6.5.9 TCP Timer Management 573
6.5.10 TCP Congestion Control 576
6.5.11 TCP CUBIC 586
6.6
TRANSPORT PROTOCOLS AND CONGESTION CONTROL 587
6.6.1 QUIC: Quick UDP Internet Connections 587
6.6.2 BBR: Congestion Control Based on Bottleneck Bandwidth 588
6.6.3 The Future of TCP 590
6.7
PERFORMANCE ISSUES 590
6.7.1 Performance Problems in Computer Networks6.7.2 Network Performance Measurement 592
6.7.3 Measuring Access Network Throughput 593
6.7.4 Measuring Quality of Experience 594
6.7.5 Host Design for Fast Networks 595
6.7.6 Fast Segment Processing 598
6.7.7 Header Compression 601
6.7.8 Protocols for Long Fat Networks 603
591
6.8
SUMMARY 607
7 THE APPLICATION LAYER
7.1
THE DOMAIN NAME SYSTEM (DNS) 613
7.1.1 History and Overview 614
7.1.2 The DNS Lookup Process 614
7.1.3 The DNS Name Space and Hierarchy 617
7.1.4 DNS Queries and Responses 620
7.1.5 Name Resolution 627
7.1.6 Hands on with DNS 629
7.1.7 DNS Privacy 629
7.1.8 Contention Over Names 631
7.2
ELECTRONIC MAIL 632
7.2.1 Architecture and Services 633
7.2.2 The User Agent 635
7.2.3 Message Formats 637
7.2.4 Message Transfer 642
7.2.5 Final Delivery 647
7.3
THE WORLD WIDE WEB 650
7.3.1 Architectural Overview 651
7.3.2 Static Web Objects 659
7.3.3 Dynamic Web Pages and Web Applications 660
7.3.4 HTTP and HTTPS 664
7.3.5 Web Privacy 676
7.4
STREAMING AUDIO AND VIDEO 680
7.4.1 Digital Audio 682
7.4.2 Digital Video 684
7.4.3 Streaming Stored Media 687
7.4.4 Real-Time Streaming 694
7.5
CONTENT DELIVERY 703
7.5.1 Content and Internet Traffic 705
7.5.2 Server Farms and Web Proxies 707
7.5.3 Content Delivery Networks 711
7.5.4 Peer-to-Peer Networks 715
7.5.5 Evolution of the Internet 721
7.6
SUMMARY 725
8 NETWORK SECURITY
731
8.1
FUNDAMENTALS OF NETWORK SECURITY8.1.1 Fundamental Security Principles 734
8.1.2 Fundamental Attack Principles 736
8.1.3 From Threats to Solutions 738
733
8.2
THE CORE INGREDIENTS OF AN ATTACK 739
8.2.1 Reconnaissance 739
8.2.2 Sniffing and Snooping (with a Dash of Spoofing)8.2.3 Spoofing (beyond ARP) 744
8.2.4 Disruption 755
8.3
8.4
FIREWALLS AND INTRUSION DETECTION SYSTEMS8.3.1 Firewalls 760
8.3.2 Intrusion Detection and Prevention 762
759
CRYPTOGRAPHY 766
8.4.1 Introduction to Cryptography 767
8.4.2 Two Fundamental Cryptographic Principles 769
8.4.3 Substitution Ciphers 771
8.4.4 Transposition Ciphers 773
8.4.5 One-Time Pads 774
8.5
SYMMETRIC-KEY ALGORITHMS 779
8.5.1 The Data Encryption Standard 780
8.5.2 The Advanced Encryption Standard 781
8.5.3 Cipher Modes 783
8.6
PUBLIC-KEY ALGORITHMS 787
8.6.1 RSA 788
8.6.2 Other Public-Key Algorithms 790
8.7
DIGITAL SIGNATURES 791
8.7.1 Symmetric-Key Signatures 791
8.7.2 Public-Key Signatures 793
8.7.3 Message Digests 795
8.7.4 The Birthday Attack 797
8.8
MANAGEMENT OF PUBLIC KEYS 799
8.8.1 Certificates 799
8.8.2 X.509 801
8.8.3 Public Key Infrastructures 802
8.9
AUTHENTICATION PROTOCOLS 805
8.9.1 Authentication Based on a Shared Secret Key 806
8.9.2 Establishing a Shared Key: The Diffie-Hellman Key Exchange8.9.3 Authentication Using a Key Distribution Center 813
8.9.4 Authentication Using Kerberos 816
8.9.5 Authentication Using Public-Key Cryptography 819
811
8.10 COMMUNICATION SECURITY 819
8.10.1 IPsec 820
8.10.2 Virtual Private Networks 824
8.10.3 Wireless Security 825
8.11 EMAIL SECURITY 829
8.11.1 Pretty Good Privacy 829
8.11.2 S/MIME 833
8.12WEB SECURITY 834
8.12.1 Threats 834
8.12.2 Secure Naming and DNSSEC 835
8.12.3 Transport Layer Security 838
8.12.4 Running Untrusted Code 842
8.13SOCIAL ISSUES 844
8.13.1 Confidential and Anonymous Communication 844
8.13.2 Freedom of Speech 847
8.13.3 Copyright 851
8.14 SUMMARY 854
