Published by Pearson (March 10, 2021) © 2020
Cisco Networking Academy
Introduction to Networks Companion Guide is the official supplemental textbook for the Introduction to Networks course in the Cisco Networking Academy CCNA curriculum.
* 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.
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.
* 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.
This book is offered exclusively for students enrolled in Cisco Networking Academy courses. It is not designed for independent study or professional certification preparation. Visit netacad.com to learn more about program options and requirements.
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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 Access—CSMA/CD (6.2.7) 217
Contention-Based Access—CSMA/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 Issues—ARP Broadcasts and ARP Spoofing (9.2.8) 307
IPv6 Neighbor Discovery (9.3) 309
IPv6 Neighbor Discovery Messages (9.3.2) 309
IPv6 Neighbor Discovery—Address 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 1—Omit Leading Zeros (12.2.2) 403
Rule 2—Double 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
Ping—Test 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
Traceroute—Test 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 Reliability—Guaranteed and Ordered Delivery (14.6.1) 486
TCP Reliability—Data Loss and Retransmission (14.6.3) 488
TCP Flow Control—Window Size and Acknowledgments (14.6.5) 490
TCP Flow Control—Maximum Segment Size (MSS) (14.6.6) 491
TCP Flow Control—Congestion 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
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 Access—CSMA/CD (6.2.7) 217
Contention-Based Access—CSMA/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 Issues—ARP Broadcasts and ARP Spoofing (9.2.8) 307
IPv6 Neighbor Discovery (9.3) 309
IPv6 Neighbor Discovery Messages (9.3.2) 309
IPv6 Neighbor Discovery—Address 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 1—Omit Leading Zeros (12.2.2) 403
Rule 2—Double 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
Ping—Test 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
Traceroute—Test 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 Reliability—Guaranteed and Ordered Delivery (14.6.1) 486
TCP Reliability—Data Loss and Retransmission (14.6.3) 488
TCP Flow Control—Window Size and Acknowledgments (14.6.5) 490
TCP Flow Control—Maximum Segment Size (MSS) (14.6.6) 491
TCP Flow Control—Congestion 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