Introduction to Networks Companion Guide (CCNAv7)

Introduction to Networks Companion Guide is the official supplemental textbook for the Introduction to Networks course in the Cisco Networking Academy CCNA curriculum.


The course introduces the architecture, protocols, functions, components, and models of the internet and computer networks. The principles of IP addressing and fundamentals of Ethernet concepts, media, and operations are introduced to provide a foundation for the curriculum. By the end of the course, you will be able to build simple LANs, perform basic configurations for routers and switches, understand the fundamentals of network security, and implement IP addressing schemes.

The Companion Guide is designed as a portable desk reference to use anytime, anywhere to reinforce the material from the course and organize your time.

The book's features help you focus on important concepts to succeed in this course:* Chapter objectives:  Review core concepts by answering the focus questions listed at the beginning of each chapter.
* Key terms:  Refer to the lists of networking vocabulary introduced and highlighted in context in each chapter.
* Glossary:  Consult the comprehensive Glossary with more than 300 terms.
* Summary of Activities and Labs:  Maximize your study time with this complete list of all associated practice exercises at the end of each chapter.
* Check Your Understanding:  Evaluate your readiness with the end-of-chapter questions that match the style of questions you see in the online course quizzes. The answer key explains each answer.


* How To:  Look for this icon to study the steps you need to learn to perform certain tasks.
* Interactive Activities:  Reinforce your understanding of topics with dozens of exercises from the online course identified throughout the book with this icon.
* Videos:  Watch the videos embedded within the online course.
* Packet Tracer Activities:  Explore and visualize networking concepts using Packet Tracer. There are multiple exercises interspersed throughout the chapters and provided in the accompanying Labs & Study Guide book.
* Hands-on Labs:  Work through all the labs and other activities that are included in the course and published in the separate Labs & Study Guide.

Sample Pages

Download the sample pages (includes Chapter 7)

Table of Contents

Introduction xxx
Chapter 1 Networking Today 1
Objectives 1
Key Terms 1
Introduction (1.0) 3
Networks Affect Our Lives (1.1) 3
    Networks Connect Us (1.1.1) 3
    No Boundaries (1.1.3) 3
Network Components (1.2) 4
    Host Roles (1.2.1) 4
    Peer-to-Peer (1.2.2) 5
    End Devices (1.2.3) 6
    Intermediary Devices (1.2.4) 6
    Network Media (1.2.5) 7
Network Representations and Topologies (1.3) 8
    Network Representations (1.3.1) 8
    Topology Diagrams (1.3.2) 10
        Physical Topology Diagrams 10
        Logical Topology Diagrams 10
Common Types of Networks (1.4) 11
    Networks of Many Sizes (1.4.1) 11
    LANs and WANs (1.4.2) 12
        LANs 13
        WANs 14
    The Internet (1.4.3) 15
    Intranets and Extranets (1.4.4) 16
Internet Connections (1.5) 17
    Internet Access Technologies (1.5.1) 17
    Home and Small Office Internet Connections (1.5.2) 18
    Businesses Internet Connections (1.5.3) 19
    The Converging Network (1.5.4) 20
Reliable Networks (1.6) 23
    Network Architecture (1.6.1) 23
    Fault Tolerance (1.6.2) 24
    Scalability (1.6.3) 24
    Quality of Service (1.6.4) 25
    Network Security (1.6.5) 26
Network Trends (1.7) 27
    Recent Trends (1.7.1) 28
    Bring Your Own Device (BYOD) (1.7.2) 28
    Online Collaboration (1.7.3) 28
    Video Communications (1.7.4) 29
    Cloud Computing (1.7.6) 29
    Technology Trends in the Home (1.7.7) 31
    Powerline Networking (1.7.8) 31
    Wireless Broadband (1.7.9) 32
        Wireless Internet Service Providers 32
        Wireless Broadband Service 32
Network Security (1.8) 33
    Security Threats (1.8.1) 33
    Security Solutions (1.8.2) 34
The IT Professional (1.9) 35
    CCNA (1.9.1) 35
    Networking Jobs (1.9.2) 36
Summary (1.10) 37
    Networks Affect Our Lives 37
    Network Components 37
    Network Representations and Topologies 37
    Common Types of Networks 37
    Internet Connections 38
    Reliable Networks 38
    Network Trends 38
    Network Security 39
    The IT Professional 40
Practice 40
Check Your Understanding Questions 40
Chapter 2 Basic Switch and End Device Configuration 45
Objectives 45
Key Terms 45
Introduction (2.0) 46
Cisco IOS Access (2.1) 46
    Operating Systems (2.1.1) 46
    GUI (2.1.2) 47
    Purpose of an OS (2.1.3) 48
    Access Methods (2.1.4) 49
    Terminal Emulation Programs (2.1.5) 50
IOS Navigation (2.2) 52
    Primary Command Modes (2.2.1) 52
    Configuration Mode and Subconfiguration Modes (2.2.2) 53
    Navigate Between IOS Modes (2.2.4) 54
    A Note About Syntax Checker Activities (2.2.6) 55
The Command Structure (2.3) 56
    Basic IOS Command Structure (2.3.1) 56
    IOS Command Syntax Check (2.3.2) 57
    IOS Help Features (2.3.3) 58
    Hot Keys and Shortcuts (2.3.5) 58
Basic Device Configuration (2.4) 61
    Device Names (2.4.1) 61
    Password Guidelines (2.4.2) 62
    Configure Passwords (2.4.3) 63
    Encrypt Passwords (2.4.4) 64
    Banner Messages (2.4.5) 65
Save Configurations (2.5) 66
    Configuration Files (2.5.1) 67
    Alter the Running Configuration (2.5.2) 68
    Capture Configuration to a Text File (2.5.4) 68
Ports and Addresses (2.6) 71
    IP Addresses (2.6.1) 71
    Interfaces and Ports (2.6.2) 73
Configure IP Addressing (2.7) 74
    Manual IP Address Configuration for End Devices (2.7.1) 75
    Automatic IP Address Configuration for End Devices (2.7.2) 76
    Switch Virtual Interface Configuration (2.7.4) 77
Verify Connectivity (2.8) 78
Summary (2.9) 79
    Cisco IOS Access 79
    IOS Navigation 79
    The Command Structure 79
    Basic Device Configuration 79
    Save Configurations 80
    Ports and Addresses 80
    Configure IP Addressing 80
    Verify Connectivity 80
Practice 81
Check Your Understanding Questions 81
Chapter 3 Protocols and Models 85
Objectives 85
Key Terms 85
Introduction (3.0) 86
The Rules (3.1) 86
    Communications Fundamentals (3.1.2) 86
    Communication Protocols (3.1.3) 87
    Rule Establishment (3.1.4) 88
    Network Protocol Requirements (3.1.5) 88
    Message Encoding (3.1.6) 89
    Message Formatting and Encapsulation (3.1.7) 90
    Message Size (3.1.8) 91
    Message Timing (3.1.9) 92
    Message Delivery Options (3.1.10) 92
    A Note About the Node Icon (3.1.11) 94
Protocols 94
    Network Protocol Overview (3.2.1) 94
    Network Protocol Functions (3.2.2) 95
    Protocol Interaction (3.2.3) 96
Protocol Suites (3.3) 97
    Network Protocol Suites (3.3.1) 97
    Evolution of Protocol Suites (3.3.2) 98
    TCP/IP Protocol Example (3.3.3) 99
    TCP/IP Protocol Suite (3.3.4) 99
        Application Layer 101
        Transport Layer 102
        Internet Layer 102
        Network Access Layer 103
    TCP/IP Communication Process (3.3.5) 103
Standards Organizations (3.4) 108
    Open Standards (3.4.1) 108
    Internet Standards (3.4.2) 108
    Electronic and Communications Standards (3.4.3) 111
Reference Models (3.5) 111
    The Benefits of Using a Layered Model (3.5.1) 112
    The OSI Reference Model (3.5.2) 112
    The TCP/IP Protocol Model (3.5.3) 114
    OSI and TCP/IP Model Comparison (3.5.4) 115
Data Encapsulation (3.6) 116
    Segmenting Messages (3.6.1) 116
    Sequencing (3.6.2) 118
    Protocol Data Units (3.6.3) 118
    Encapsulation Example (3.6.4) 120
    De-encapsulation Example (3.6.5) 120
Data Access (3.7) 121
    Addresses (3.7.1) 121
    Layer 3 Logical Address (3.7.2) 122
    Devices on the Same Network (3.7.3) 123
    Role of the Data Link Layer Addresses: Same
    IP Network (3.7.4) 124
    Devices on a Remote Network (3.7.5) 125
    Role of the Network Layer Addresses (3.7.6) 125
    Role of the Data Link Layer Addresses: Different
    IP Networks (3.7.7) 126
    Data Link Addresses (3.7.8) 127
Summary (3.8) 130
    The Rules 130
    Protocols 130
    Protocol Suites 130
    Standards Organizations 131
    Reference Models 131
    Data Encapsulation 132
    Data Access 132
Practice 133
Check Your Understanding Questions 133
Chapter 4 Physical Layer 137
Objectives 137
Key Terms 137
Introduction (4.0) 138
Purpose of the Physical Layer (4.1) 138
    The Physical Connection (4.1.1) 138
    The Physical Layer (4.1.2) 139
Physical Layer Characteristics (4.2) 141
    Physical Layer Standards (4.2.1) 141
    Physical Components (4.2.2) 142
    Encoding (4.2.3) 142
    Signaling (4.2.4) 143
    Bandwidth (4.2.5) 145
    Bandwidth Terminology (4.2.6) 145
        Latency 146
        Throughput 146
        Goodput 146
Copper Cabling (4.3) 146
    Characteristics of Copper Cabling (4.3.1) 147
    Types of Copper Cabling (4.3.2) 148
    Unshielded Twisted-Pair (UTP) (4.3.3) 148
    Shielded Twisted-Pair (STP) (4.3.4) 150
    Coaxial Cable (4.3.5) 151
UTP Cabling (4.4) 152
    Properties of UTP Cabling (4.4.1) 152
    UTP Cabling Standards and Connectors (4.4.2) 153
    Straight-Through and Crossover UTP Cables (4.4.3) 157
Fiber-Optic Cabling (4.5) 158
    Properties of Fiber-Optic Cabling (4.5.1) 158
    Types of Fiber Media (4.5.2) 159
        Single-Mode Fiber 159
        Multimode Fiber 160
    Fiber-Optic Cabling Usage (4.5.3) 160
    Fiber-Optic Connectors (4.5.4) 161
    Fiber Patch Cords (4.5.5) 162
    Fiber Versus Copper (4.5.6) 163
Wireless Media (4.6) 164
    Properties of Wireless Media (4.6.1) 164
    Types of Wireless Media (4.6.2) 165
    Wireless LAN (4.6.3) 166
Summary (4.7) 168
    Purpose of the Physical Layer 168
    Physical Layer Characteristics 168
    Copper Cabling 168
    UTP Cabling 169
    Fiber-Optic Cabling 169
    Wireless Media 169
Practice 170
Check Your Understanding Questions 170
Chapter 5 Number Systems 175
Objectives 175
Key Terms 175
Introduction (5.0) 176
Binary Number System (5.1) 176
    Binary and IPv4 Addresses (5.1.1) 176
    Binary Positional Notation (5.1.3) 178
    Convert Binary to Decimal (5.1.5) 180
    Decimal to Binary Conversion (5.1.7) 182
    Decimal to Binary Conversion Example (5.1.8) 186
    IPv4 Addresses (5.1.11) 193
Hexadecimal Number System (5.2) 194
    Hexadecimal and IPv6 Addresses (5.2.1) 194
    Decimal to Hexadecimal Conversions (5.2.3) 196
    Hexadecimal to Decimal Conversion (5.2.4) 196
Summary (5.3) 198
    Binary Number System 198
    Hexadecimal Number System 198
Practice 198
Check Your Understanding Questions 198
Chapter 6 Data Link Layer 203
Objectives 203
Key Terms 203
Introduction (6.0) 204
Purpose of the Data Link Layer (6.1) 204
    The Data Link Layer (6.1.1) 204
    IEEE 802 LAN/MAN Data Link Sublayers (6.1.2) 206
    Providing Access to Media (6.1.3) 207
    Data Link Layer Standards (6.1.4) 209
Topologies (6.2) 209
    Physical and Logical Topologies (6.2.1) 209
    WAN Topologies (6.2.2) 211
        Point-to-Point 211
        Hub and Spoke 211
        Mesh 212
    Point-to-Point WAN Topology (6.2.3) 213
    LAN Topologies (6.2.4) 213
        Legacy LAN Topologies 214
    Half-Duplex and Full-Duplex Communication (6.2.5) 215
        Half-Duplex Communication 215
        Full-Duplex Communication 215
    Access Control Methods (6.2.6) 216
        Contention-Based Access 216
        Controlled Access 217
    Contention-Based AccessCSMA/CD (6.2.7) 217
    Contention-Based AccessCSMA/CA (6.2.8) 219
Data Link Frame (6.3) 221
    The Frame (6.3.1) 221
    Frame Fields (6.3.2) 222
    Layer 2 Addresses (6.3.3) 223
    LAN and WAN Frames (6.3.4) 225
Summary (6.4) 228
    Purpose of the Data Link Layer 228
    Topologies 228
    Data Link Frame 229
Practice 229
Check Your Understanding Questions 229
Chapter 7 Ethernet Switching 233
Objectives 233
Key Terms 233
Introduction (7.0) 234
Ethernet Frames (7.1) 234
    Ethernet Encapsulation (7.1.1) 234
    Data Link Sublayers (7.1.2) 235
    MAC Sublayer (7.1.3) 236
        Data Encapsulation 236
        Accessing the Media 237
    Ethernet Frame Fields (7.1.4) 237
Ethernet MAC Address (7.2) 239
    MAC Address and Hexadecimal (7.2.1) 240
    Ethernet MAC Address (7.2.2) 241
    Frame Processing (7.2.3) 243
    Unicast MAC Address (7.2.4) 244
    Broadcast MAC Address (7.2.5) 246
    Multicast MAC Address (7.2.6) 247
The MAC Address Table (7.3) 248
    Switch Fundamentals (7.3.1) 248
    Switch Learning and Forwarding (7.3.2) 250
        Examine the Source MAC Address 250
        Find the Destination MAC Address 250
    Filtering Frames (7.3.3) 252
Switch Speeds and Forwarding Methods (7.4) 254
    Frame Forwarding Methods on Cisco Switches (7.4.1) 254
    Cut-Through Switching (7.4.2) 255
    Memory Buffering on Switches (7.4.3) 257
    Duplex and Speed Settings (7.4.4) 257
    Auto-MDIX (7.4.5) 259
Summary (7.5) 261
    Ethernet Frame 261
    Ethernet MAC Address 261
    The MAC Address Table 261
    Switch Speeds and Forwarding Methods 262
Practice 262
Check Your Understanding Questions 262
Chapter 8 Network Layer 267
Objectives 267
Key Terms 267
Introduction (8.0) 268
Network Layer Characteristics (8.1) 268
    The Network Layer (8.1.1) 268
    IP Encapsulation (8.1.2) 270
    Characteristics of IP (8.1.3) 271
    Connectionless (8.1.4) 271
    Best Effort (8.1.5) 272
    Media Independent (8.1.6) 273
IPv4 Packet (8.2) 274
    IPv4 Packet Header (8.2.1) 274
    IPv4 Packet Header Fields (8.2.2) 274
IPv6 Packet (8.3) 276
    Limitations of IPv4 (8.3.1) 277
    IPv6 Overview (8.3.2) 277
    IPv4 Packet Header Fields in the IPv6 Packet Header (8.3.3) 278
    IPv6 Packet Header (8.3.4) 280
How a Host Routes (8.4) 281
    Host Forwarding Decision (8.4.1) 281
    Default Gateway (8.4.2) 282
    A Host Routes to the Default Gateway (8.4.3) 283
    Host Routing Tables (8.4.4) 283
Introduction to Routing (8.5) 285
    Router Packet Forwarding Decision (8.5.1) 285
    IP Router Routing Table (8.5.2) 286
    Static Routing (8.5.3) 287
    Dynamic Routing (8.5.4) 288
    Introduction to an IPv4 Routing Table (8.5.6) 290
Summary (8.6) 292
    Network Layer Characteristics 292
    IPv4 Packet 292
    IPv6 Packet 292
    How a Host Routes 293
    Introduction to Routing 293
Practice 294
Check Your Understanding Questions 294
Chapter 9 Address Resolution 297
Objectives 297
Key Terms 297
Introduction (9.0) 298
MAC and IP (9.1) 298
    Destination on Same Network (9.1.1) 298
    Destination on Remote Network (9.1.2) 299
ARP (9.2) 301
    ARP Overview (9.2.1) 301
    ARP Functions (9.2.2) 302
    Removing Entries from an ARP Table (9.2.6) 306
    ARP Tables on Networking Devices (9.2.7) 306
    ARP IssuesARP Broadcasts and ARP Spoofing (9.2.8) 307
IPv6 Neighbor Discovery (9.3) 309
    IPv6 Neighbor Discovery Messages (9.3.2) 309
    IPv6 Neighbor DiscoveryAddress Resolution (9.3.3) 311
Summary (9.4) 313
    MAC and IP 313
    ARP 313
    Neighbor Discovery 314
Practice 314
Check Your Understanding Questions 314
Chapter 10 Basic Router Configuration 319
Objectives 319
Introduction (10.0) 320
Configure Initial Router Settings (10.1) 320
    Basic Router Configuration Steps (10.1.1) 320
    Basic Router Configuration Example (10.1.2) 321
Configure Interfaces (10.2) 323
    Configure Router Interfaces (10.2.1) 323
    Configure Router Interfaces Example (10.2.2) 324
    Verify Interface Configuration (10.2.3) 325
    Configuration Verification Commands (10.2.4) 326
Configure the Default Gateway (10.3) 330
    Default Gateway on a Host (10.3.1) 331
    Default Gateway on a Switch (10.3.2) 332
Summary (10.4) 335
    Configure Initial Router Settings 335
    Configure Interfaces 335
    Configure the Default Gateway 335
Practice 336
Check Your Understanding Questions 337
Chapter 11 IPv4 Addressing 341
Objectives 341
Key Terms 341
Introduction (11.0) 342
IPv4 Address Structure (11.1) 342
    Network and Host Portions (11.1.1) 342
    The Subnet Mask (11.1.2) 343
    The Prefix Length (11.1.3) 344
    Determining the Network: Logical AND (11.1.4) 345
    Network, Host, and Broadcast Addresses (11.1.6) 347
        Network Address 347
        Host Addresses 348
        Broadcast Address 349
IPv4 Unicast, Broadcast, and Multicast (11.2) 349
    Unicast (11.2.1) 349
    Broadcast (11.2.2) 350
        IP Directed Broadcasts 351
    Multicast (11.2.3) 352
Types of IPv4 Addresses (11.3) 353
    Public and Private IPv4 Addresses (11.3.1) 353
    Routing to the Internet (11.3.2) 354
    Special Use IPv4 Addresses (11.3.4) 356
        Loopback Addresses 356
        Link-Local Addresses 357
    Legacy Classful Addressing (11.3.5) 357
    Assignment of IP Addresses (11.3.6) 358
Network Segmentation (11.4) 359
    Broadcast Domains and Segmentation (11.4.1) 359
    Problems with Large Broadcast Domains (11.4.2) 360
    Reasons for Segmenting Networks (11.4.3) 362
Subnet an IPv4 Network (11.5) 364
    Subnet on an Octet Boundary (11.5.1) 364
    Subnet Within an Octet Boundary (11.5.2) 366
Subnet a Slash 16 and a Slash 8 Prefix (11.6) 367
    Create Subnets with a Slash 16 Prefix (11.6.1) 367
    Create 100 Subnets with a Slash 16 Prefix (11.6.2) 369
    Create 1000 Subnets with a Slash 8 Prefix (11.6.3) 372
Subnet to Meet Requirements (11.7) 374
    Subnet Private Versus Public IPv4 Address Space (11.7.1) 374
        What About the DMZ? 377
    Minimize Unused Host IPv4 Addresses and Maximize Subnets (11.7.2) 377
    Example: Efficient IPv4 Subnetting (11.7.3) 378
VLSM (11.8) 381
    IPv4 Address Conservation (11.8.3) 381
    VLSM (11.8.4) 383
    VLSM Topology Address Assignment (11.8.5) 386
Structured Design (11.9) 387
    IPv4 Network Address Planning (11.9.1) 388
    Device Address Assignment (11.9.2) 389
Summary (11.10) 390
    IPv4 Addressing Structure 390
    IPv4 Unicast, Broadcast, and Multicast 390
    Types of IPv4 Addresses 390
    Network Segmentation 391
    Subnet an IPv4 Network 391
    Subnet a /16 and a /8 Prefix 391
    Subnet to Meet Requirements 391
    Variable-Length Subnet Masking 392
    Structured Design 392
Practice 393
Check Your Understanding Questions 393
Chapter 12 IPv6 Addressing 397
Objectives 397
Key Terms 397
Introduction (12.0) 398
IPv4 Issues (12.1) 398
    Need for IPv6 (12.1.1) 398
    Internet of Things 399
    IPv4 and IPv6 Coexistence (12.1.2) 399
        Dual Stack 399
        Tunneling 400
        Translation 401
IPv6 Address Representation (12.2) 401
    IPv6 Addressing Formats (12.2.1) 401
        Preferred Format 402
    Rule 1Omit Leading Zeros (12.2.2) 403
    Rule 2Double Colon (12.2.3) 404
IPv6 Address Types (12.3) 406
    Unicast, Multicast, Anycast (12.3.1) 406
    IPv6 Prefix Length (12.3.2) 406
    Types of IPv6 Unicast Addresses (12.3.3) 407
    A Note About the Unique Local Address (12.3.4) 408
    IPv6 GUA (12.3.5) 408
    IPv6 GUA Structure (12.3.6) 409
        Global Routing Prefix 410
        Subnet ID 410
        Interface ID 410
    IPv6 LLA (12.3.7) 411
GUA and LLA Static Configuration (12.4) 413
    Static GUA Configuration on a Router (12.4.1) 413
    Static GUA Configuration on a Windows Host (12.4.2) 414
    Static Configuration of a Link-Local Unicast Address (12.4.3) 415
Dynamic Addressing for IPv6 GUAs (12.5) 417
    RS and RA Messages (12.5.1) 417
    Method 1: SLAAC (12.5.2) 418
    Method 2: SLAAC and Stateless DHCPv6 (12.5.3) 419
    Method 3: Stateful DHCPv6 (12.5.4) 420
    EUI-64 Process vs. Randomly Generated (12.5.5) 421
    EUI-64 Process (12.5.6) 422
    Randomly Generated Interface IDs (12.5.7) 424
Dynamic Addressing for IPv6 LLAs (12.6) 425
    Dynamic LLAs (12.6.1) 425
    Dynamic LLAs on Windows (12.6.2) 425
    Dynamic LLAs on Cisco Routers (12.6.3) 426
    Verify IPv6 Address Configuration (12.6.4) 427
IPv6 Multicast Addresses (12.7) 430
    Assigned IPv6 Multicast Addresses (12.7.1) 430
    Well-Known IPv6 Multicast Addresses (12.7.2) 430
    Solicited-Node IPv6 Multicast Addresses (12.7.3) 432
Subnet an IPv6 Network (12.8) 432
    Subnet Using the Subnet ID (12.8.1) 432
    IPv6 Subnetting Example (12.8.2) 433
    IPv6 Subnet Allocation (12.8.3) 434
    Router Configured with IPv6 Subnets (12.8.4) 435
Summary (12.9) 436
    IPv4 Issues 436
    IPv6 Address Representation 436
    IPv6 Address Types 436
    GUA and LLA Static Configuration 437
    Dynamic Addressing for IPv6 GUAs 437
    Dynamic Addressing for IPv6 LLAs 437
    IPv6 Multicast Addresses 438
    Subnet an IPv6 Network 438
Practice 439
Check Your Understanding Questions 439
Chapter 13 ICMP 443
Objectives 443
Introduction (13.0) 444
ICMP Messages (13.1) 444
    ICMPv4 and ICMPv6 Messages (13.1.1) 444
    Host Reachability (13.1.2) 444
    Destination or Service Unreachable (13.1.3) 445
    Time Exceeded (13.1.4) 446
    ICMPv6 Messages (13.1.5) 446
Ping and Traceroute Tests (13.2) 449
    PingTest Connectivity (13.2.1) 449
    Ping the Loopback (13.2.2) 450
    Ping the Default Gateway (13.2.3) 450
    Ping a Remote Host (13.2.4) 451
    TracerouteTest the Path (13.2.5) 452
        Round-Trip Time (RTT) 453
        IPv4 TTL and IPv6 Hop Limit 453
Summary (13.3) 454
    ICMP Messages 454
    Ping and Traceroute Testing 454
Practice 455
Check Your Understanding Questions 456
Chapter 14 Transport Layer 461
Objectives 461
Key Terms 461
Introduction (14.0) 462
Transportation of Data (14.1) 462
    Role of the Transport Layer (14.1.1) 462
    Transport Layer Responsibilities (14.1.2) 463
    Transport Layer Protocols (14.1.3) 467
    Transmission Control Protocol (TCP) (14.1.4) 467
    User Datagram Protocol (UDP) (14.1.5) 468
    The Right Transport Layer Protocol for the Right Application (14.1.6) 469
TCP Overview (14.2) 470
    TCP Features (14.2.1) 470
    TCP Header (14.2.2) 471
    TCP Header Fields (14.2.3) 471
    Applications That Use TCP (14.2.4) 472
UDP Overview (14.3) 473
    UDP Features (14.3.1) 473
    UDP Header (14.3.2) 474
    UDP Header Fields (14.3.3) 474
    Applications that use UDP (14.3.4) 475
Port Numbers (14.4) 476
    Multiple Separate Communications (14.4.1) 476
    Socket Pairs (14.4.2) 477
    Port Number Groups (14.4.3) 478
    The netstat Command (14.4.4) 479
TCP Communication Process (14.5) 480
    TCP Server Processes (14.5.1) 480
    TCP Connection Establishment (14.5.2) 483
    Session Termination (14.5.3) 484
    TCP Three-Way Handshake Analysis (14.5.4) 485
Reliability and Flow Control (14.6) 486
    TCP ReliabilityGuaranteed and Ordered Delivery (14.6.1) 486
    TCP ReliabilityData Loss and Retransmission (14.6.3) 488
    TCP Flow ControlWindow Size and Acknowledgments (14.6.5) 490
    TCP Flow ControlMaximum Segment Size (MSS) (14.6.6) 491
    TCP Flow ControlCongestion Avoidance (14.6.7) 493
UDP Communication (14.7) 494
    UDP Low Overhead Versus Reliability (14.7.1) 494
    UDP Datagram Reassembly (14.7.2) 494
    UDP Server Processes and Requests (14.7.3) 495
    UDP Client Processes (14.7.4) 495
Summary (14.8) 499
    Transportation of Data 499
    TCP Overview 499
    UDP Overview 499
    Port Numbers 499
    TCP Communications Process 500
    Reliability and Flow Control 500
    UDP Communication 501
Practice 501
Check Your Understanding Questions 502
Chapter 15 Application Layer 507
Objectives 507
Key Terms 507
Introduction (15.0) 508
Application, Presentation, and Session (15.1) 508
    Application Layer (15.1.1) 508
    Presentation and Session Layer (15.1.2) 508
    TCP/IP Application Layer Protocols (15.1.3) 510
Peer-to-Peer (15.2) 511
    Client-Server Model (15.2.1) 511
    Peer-to-Peer Networks (15.2.2) 512
    Peer-to-Peer Applications (15.2.3) 513
    Common P2P Applications (15.2.4) 514
Web and Email Protocols (15.3) 515
    Hypertext Transfer Protocol and Hypertext Markup Language (15.3.1) 515
    HTTP and HTTPS (15.3.2) 516
    Email Protocols (15.3.3) 518
    SMTP, POP, and IMAP (15.3.4) 519
        SMTP 519
        POP 520
        IMAP 521
IP Addressing Services (15.4) 521
    Domain Name Service (15.4.1) 522
    DNS Message Format (15.4.2) 524
    DNS Hierarchy (15.4.3) 525
    The nslookup Command (15.4.4) 526
    Dynamic Host Configuration Protocol (15.4.6) 527
    DHCP Operation (15.4.7) 528
File Sharing Services (15.5) 530
    File Transfer Protocol (15.5.1) 530
    Server Message Block (15.5.2) 531
Summary 534
    Application, Presentation, and Session 534
    Peer-to-Peer 534
    Web and Email Protocols 534
    IP Addressing Services 535
    File Sharing Services 535
Practice 536
Check Your Understanding Questions 536
Chapter 16 Network Security Fundamentals 541
Objectives 541
Key Terms 541
Introduction (16.0) 542
Security Threats and Vulnerabilities (16.1) 542
    Types of Threats (16.1.1) 542
    Types of Vulnerabilities (16.1.2) 543
    Physical Security (16.1.3) 545
Network Attacks (16.2) 546
    Types of Malware (16.2.1) 546
        Viruses 546
        Worms 547
        Trojan Horses 547
    Reconnaissance Attacks (16.2.2) 547
    Access Attacks (16.2.3) 548
        Password Attacks 548
        Trust Exploitation 548
        Port Redirection 549
        Man-in-the-Middle 549
    Denial of Service Attacks (16.2.4) 551
        DoS Attack 551
        DDoS Attack 551
Network Attack Mitigations (16.3) 552
    The Defense-in-Depth Approach (16.3.1) 553
    Keep Backups (16.3.2) 553
    Upgrade, Update, and Patch (16.3.3) 554
    Authentication, Authorization, and Accounting (16.3.4) 555
    Firewalls (16.3.5) 555
    Types of Firewalls (16.3.6) 557
    Endpoint Security (16.3.7) 558
Device Security (16.4) 558
    Cisco AutoSecure (16.4.1) 558
    Passwords (16.4.2) 559
    Additional Password Security (16.4.3) 560
    Enable SSH (16.4.4) 561
    Disable Unused Services (16.4.5) 563
Summary 565
    Security Threats and Vulnerabilities 565
    Network Attacks 565
    Network Attack Mitigation 565
    Device Security 566
Practice 567
Check Your Understanding Questions 567
Chapter 17 Build a Small Network 571
Objectives 571
Key Terms 571
Introduction (17.0) 572
Devices in a Small Network (17.1) 572
    Small Network Topologies (17.1.1) 572
    Device Selection for a Small Network (17.1.2) 573
        Cost 573
        Speed and Types of Ports/Interfaces 573
        Expandability 573
        Operating System Features and Services 574
    IP Addressing for a Small Network (17.1.3) 574
    Redundancy in a Small Network (17.1.4) 576
    Traffic Management (17.1.5) 577
Small Network Applications and Protocols (17.2) 578
    Common Applications (17.2.1) 578
        Network Applications 578
        Application Layer Services 579
    Common Protocols (17.2.2) 579
    Voice and Video Applications (17.2.3) 582
Scale to Larger Networks (17.3) 583
    Small Network Growth (17.3.1) 583
    Protocol Analysis (17.3.2) 583
    Employee Network Utilization (17.3.3) 584
Verify Connectivity (17.4) 586
    Verify Connectivity with Ping (17.4.1) 586
    Extended Ping (17.4.2) 588
    Verify Connectivity with Traceroute (17.4.3) 590
    Extended Traceroute (17.4.4) 592
    Network Baseline (17.4.5) 593
Host and IOS Commands (17.5) 596
    IP Configuration on a Windows Host (17.5.1) 596
    IP Configuration on a Linux Host (17.5.2) 599
    IP Configuration on a macOS Host (17.5.3) 600
    The arp Command (17.5.4) 601
    Common show Commands Revisited (17.5.5) 602
    The show cdp neighbors Command (17.5.6) 609
    The show ip interface brief Command (17.5.7) 610
        Verify Switch Interfaces 611
Troubleshooting Methodologies (17.6) 611
    Basic Troubleshooting Approaches (17.6.1) 612
    Resolve or Escalate? (17.6.2) 613
    The debug Command (17.6.3) 613
    The terminal monitor Command (17.6.4) 615
Troubleshooting Scenarios (17.7) 616
    Duplex Operation and Mismatch Issues (17.7.1) 617
    IP Addressing Issues on IOS Devices (17.7.2) 618
    IP Addressing Issues on End Devices (17.7.3) 619
    Default Gateway Issues (17.7.4) 619
    Troubleshooting DNS Issues (17.7.5) 621
Summary (17.8) 624
    Devices in a Small Network 624
    Small Network Applications and Protocols 624
    Scale to Larger Networks 624
    Verify Connectivity 625
    Host and IOS Commands 625
    Troubleshooting Methodologies 626
    Troubleshooting Scenarios 626
Practice 627
Check Your Understanding Questions 628
Appendix A Answers to Check Your Understanding Questions 631
Key Terms Glossary 645


9780136633662   TOC   6/3/2020

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