Table of Contents
Introduction xxv
Assessment Test l
Part I ICND1 1
Chapter 1 Internetworking 3
Internetworking Basics 4
Internetworking Models 13
The Layered Approach 13
Advantages of Reference Models 14
The OSI Reference Model 15
The Application Layer 17
The Presentation Layer 18
The Session Layer 18
The Transport Layer 18
The Network Layer 24
The Data Link Layer 26
The Physical Layer 29
Summary 31
Exam Essentials 31
Written Labs 32
Written Lab 1.1: OSI Questions 32
Written Lab 1.2: Defining the OSI Layers and Devices 34
Written Lab 1.3: Identifying Collision and Broadcast Domains 34
Review Questions 36
Chapter 2 Ethernet Networking and Data Encapsulation 41
Ethernet Networks in Review 42
Collision Domain 43
Broadcast Domain 44
CSMA/CD 45
Half- and Full-Duplex Ethernet 47
Ethernet at the Data Link Layer 49
Ethernet at the Physical Layer 55
Ethernet Cabling 59
Straight-Through Cable 59
Crossover Cable 60
Rolled Cable 62
Fiber Optic 64
Data Encapsulation 66
The Cisco Three-Layer Hierarchical Model 69
The Core Layer 71
The Distribution Layer 71
The Access Layer 72
Summary 72
Exam Essentials 73
Written Labs 74
Written Lab 2.1: Binary/Decimal/Hexadecimal Conversion 74
Written Lab 2.2: CSMA/CD Operations 77
Written Lab 2.3: Cabling 78
Written Lab 2.4: Encapsulation 78
Review Questions 79
Chapter 3 Introduction to TCP/IP 85
Introducing TCP/IP 86
A Brief History of TCP/IP 87
TCP/IP and the DoD Model 87
The Process/Application Layer Protocols 89
The Host-to-Host or Transport Layer Protocols 99
The Internet Layer Protocols 108
IP Addressing 116
IP Terminology 116
The Hierarchical IP Addressing Scheme 117
Private IP Addresses (RFC 1918) 122
IPv4 Address Types 123
Layer 2 Broadcasts 124
Layer 3 Broadcasts 124
Unicast Address 125
Multicast Address 126
Summary 127
Exam Essentials 127
Written Labs 129
Written Lab 3.1: TCP/IP 129
Written Lab 3.2: Mapping Applications to the DoD Model 129
Review Questions 131
Chapter 4 Easy Subnetting 135
Subnetting Basics 136
How to Create Subnets 138
Subnet Masks 138
Classless Inter-Domain Routing (CIDR) 140
IP Subnet-Zero 142
Subnetting Class C Addresses 142
Subnetting Class B Addresses 154
Subnetting Class A Addresses 163
Summary 166
Exam Essentials 166
Written Labs 167
Written Lab 4.1: Written Subnet Practice #1 167
Written Lab 4.2: Written Subnet Practice #2 168
Written Lab 4.3: Written Subnet Practice #3 169
Review Questions 170
Chapter 5 VLSMs, Summarization, and Troubleshooting TCP/IP 175
Variable Length Subnet Masks (VLSMs) 176
VLSM Design 178
Implementing VLSM Networks 179
Summarization 186
Troubleshooting IP Addressing 189
Determining IP Address Problems 192
Summary 196
Exam Essentials 197
Written Lab 5 198
Lab 5.1: Summarization Practice 198
Review Questions 199
Chapter 6 Cisco’s Internetworking Operating System (IOS) 205
The IOS User Interface 206
Cisco IOS 206
Connecting to a Cisco IOS Device 207
Bringing Up a Switch 209
Command-Line Interface (CLI) 209
Entering the CLI 210
Overview of Router Modes 210
CLI Prompts 211
Editing and Help Features 213
Administrative Configurations 218
Hostnames 219
Banners 219
Setting Passwords 221
Encrypting Your Passwords 227
Descriptions 229
Router and Switch Interfaces 231
Bringing Up an Interface 234
Viewing, Saving, and Erasing Configurations 240
Deleting the Configuration and Reloading the Device 242
Verifying Your Configuration 242
Summary 255
Exam Essentials 256
Written Lab 6: IOS Understanding 259
Hands-on Labs 259
Hands-on Lab 6.1: Erasing an Existing Configuration 260
Hands-on Lab 6.2: Exploring User, Privileged, and Configuration Modes 260
Hands-on Lab 6.3: Using the Help and Editing Features 261
Hands-on Lab 6.4: Saving a Configuration 262
Hands-on Lab 6.5: Setting Passwords 263
Hands-on Lab 6.6: Setting the Hostname, Descriptions, IP Address, and Clock Rate 265
Review Questions 267
Chapter 7 Managing a Cisco Internetwork 273
The Internal Components of a Cisco Router and Switch 274
The Router and Switch Boot Sequence 275
Backing Up and Restoring the Cisco Configuration 276
Backing Up the Cisco Configuration 277
Restoring the Cisco Configuration 279
Erasing the Configuration 279
Configuring DHCP 280
DHCP Relay 281
Verifying DHCP on Cisco IOS 282
Syslog 283
Configuring and Verifying Syslog 285
Network Time Protocol (NTP) 288
Exploring Connected Devices Using CDP and LLDP 289
Getting CDP Timers and Holdtime Information 290
Gathering Neighbor Information 291
Documenting a Network Topology Using CDP 295
Using Telnet 298
Telnetting into Multiple Devices Simultaneously 300
Checking Telnet Connections 300
Checking Telnet Users 301
Closing Telnet Sessions 301
Resolving Hostnames 302
Building a Host Table 302
Using DNS to Resolve Names 304
Checking Network Connectivity and Troubleshooting 306
Using the ping Command 306
Using the traceroute Command 307
Debugging 308
Using the show processes Command 310
Summary 311
Exam Essentials 311
Written Labs 7 313
Written Lab 7.1: IOS Management 313
Written Lab 7.2: Router Memory 314
Hands-on Labs 314
Hands-on Lab 7.1: Backing Up the Router Configuration 315
Hands-on Lab 7.2: Using the Cisco Discovery Protocol (CDP) 315
Hands-on Lab 7.3: Using Telnet 316
Hands-on Lab 7.4: Resolving Hostnames 317
Review Questions 319
Chapter 8 Managing Cisco Devices 323
Managing the Configuration Register 324
Understanding the Configuration Register Bits 324
Checking the Current Configuration Register Value 326
Boot System Commands 327
Recovering Passwords 328
Backing Up and Restoring the Cisco IOS 331
Verifying Flash Memory 332
Backing Up the Cisco IOS 333
Restoring or Upgrading the Cisco Router IOS 334
Using the Cisco IOS File System (Cisco IFS) 337
Licensing 341
Right-To-Use Licenses (Evaluation Licenses) 344
Backing Up and Uninstalling the License 347
Summary 348
Exam Essentials 348
Written Lab 8 349
Written Lab 8.1: IOS Management 350
Hands-on Labs 350
Hands-on Lab 8.1: Backing Up Your Router IOS 350
Hands-on Lab 8.2: Upgrading or Restoring Your Router IOS 351
Review Questions 352
Chapter 9 IP Routing 357
Routing Basics 359
The IP Routing Process 361
The Cisco Router Internal Process 366
Testing Your IP Routing Understanding 367
Configuring IP Routing 372
Corp Configuration 373
SF Configuration 375
LA Configuration 379
Configuring IP Routing in Our Network 381
Static Routing 382
Default Routing 387
Dynamic Routing 390
Routing Protocol Basics 390
Routing Information Protocol (RIP) 392
Configuring RIP Routing 393
Holding Down RIP Propagations 396
Summary 399
Exam Essentials 399
Written Lab 9 400
Hands-on Labs 401
Hands-on Lab 9.1: Creating Static Routes 402
Hands-on Lab 9.2: Configuring RIP Routing 403
Review Questions 405
Chapter 10 Layer 2 Switching 411
Switching Services 412
Three Switch Functions at Layer 2 413
Port Security 417
Configuring Catalyst Switches 422
Catalyst Switch Configuration 423
Verifying Cisco Catalyst Switches 430
Summary 433
Exam Essentials 433
Written Lab 10 434
Hands-on Labs 434
Lab 10.1: Configuring Layer 2 Switches 435
Lab 10.2: Verifying Layer 2 Switches 436
Lab 10.3: Configuring Port Security 437
Review Questions 438
Chapter 11 VLANs and Inter-VLAN Routing 443
VLAN Basics 444
Broadcast Control 447
Security 448
Flexibility and Scalability 448
Identifying VLANs 449
Frame Tagging 451
VLAN Identification Methods 452
Routing between VLANs 454
Configuring VLANs 456
Assigning Switch Ports to VLANs 459
Configuring Trunk Ports 461
Configuring Inter-VLAN Routing 465
Summary 472
Exam Essentials 472
Written Lab 11 473
Hands-on Labs 473
Hands-on Lab 11.1: Configuring and Verifying VLANs 474
Hands-on Lab 11.2: Configuring and Verifying Trunk Links 474
Hands-on Lab 11.3: Configuring Router on a Stick Routing 475
Hands-on Lab 11.4: Configuring IVR with a Layer 3 Switch 476
Review Questions 477
Chapter 12 Security 483
Perimeter, Firewall, and Internal Routers 484
Introduction to Access Lists 485
Mitigating Security Issues with ACLs 488
Standard Access Lists 489
Wildcard Masking 490
Standard Access List Example 492
Controlling VTY (Telnet/SSH) Access 496
Extended Access Lists 497
Extended Access List Example 1 501
Extended Access List Example 2 503
Extended Access List Example 3 504
Named ACLs 505
Remarks 507
Monitoring Access Lists 508
Summary 510
Exam Essentials 511
Written Lab 12 511
Hands-on Labs 512
Hands-on Lab 12.1: Standard IP Access Lists 513
Hands-on Lab 12.2: Extended IP Access Lists 514
Review Questions 517
Chapter 13 Network Address Translation (NAT) 521
When Do We Use NAT? 522
Types of Network Address Translation 524
NAT Names 524
How NAT Works 525
Static NAT Configuration 527
Dynamic NAT Configuration 527
PAT (Overloading) Configuration 528
Simple Verification of NAT 529
Testing and Troubleshooting NAT 529
Summary 535
Exam Essentials 535
Written Lab 13 535
Hands-on Labs 536
Lab 13.1: Preparing for NAT 537
Lab 13.2: Configuring Dynamic NAT 538
Lab 13.3: Configuring PAT 540
Review Questions 542
Chapter 14 Internet Protocol Version 6 (IPv6) 547
Why Do We Need IPv6? 549
The Benefits and Uses of IPv6 549
IPv6 Addressing and Expressions 551
Shortened Expression 551
Address Types 552
Special Addresses 554
How IPv6 Works in an Internetwork 555
Manual Address Assignment 555
Stateless Autoconfiguration (eui-64) 556
DHCPv6 (Stateful) 559
IPv6 Header 559
ICMPv6 561
IPv6 Routing Protocols 565
Static Routing with IPv6 565
Configuring IPv6 on Our Internetwork 566
Configuring Routing on Our Internetwork 569
Summary 572
Exam Essentials 573
Written Labs 14 573
Written Lab 14.1 573
Written Lab 14.2 574
Hands-on Labs 574
Hands-on Lab 14.1: Manual and Stateful Autoconfiguration 574
Hands-on Lab 14.2: Static and Default Routing 576
Review Questions 577
Part II ICND2 581
Chapter 15 Enhanced Switched Technologies 583
VLAN Review 584
Assigning Switch Ports to VLANs 587
Configuring Trunk Ports 589
VLAN Trunking Protocol (VTP) 593
VTP Modes of Operation 594
VTP Pruning 596
Configuring VTP 597
Troubleshooting VTP 598
Spanning Tree Protocol (STP) 602
Spanning-Tree Terms 603
Spanning-Tree Operations 607
Types of Spanning-tree Protocols 610
Common Spanning Tree 610
Per-VLAN Spanning Tree+ 611
Modifying and Verifying the Bridge ID 618
Spanning-Tree Failure Consequences 623
PortFast and BPDU Guard 625
BPDU Guard 627
EtherChannel 629
Configuring and Verifying Port Channels 630
Summary 634
Exam Essentials 635
Written Lab 15 635
Hands-on Labs 636
Hands-on Lab 15.1: Verifying STP and Finding Your Root Bridge 637
Hands-on Lab 15.2: Configuring and Verifying Your Root Bridge 638
Hands-on Lab 15.3: Configuring PortFast and BPDU Guard 640
Hands-on Lab 15.4: Configuring and Verifying EtherChannel 641
Review Questions 643
Chapter 16 Network Device Management and Security 649
Mitigating Threats at the Access Layer 650
External Authentication Options 653
RADIUS 653
TACACS+ 654
SNMP 655
Management Information Base (MIB) 656
Configuring SNMP 657
Client Redundancy Issues 659
Introducing First Hop Redundancy Protocols (FHRPs) 661
Hot Standby Router Protocol (HSRP) 662
Virtual MAC Address 664
HSRP Timers 665
Group Roles 667
Configuring and Verifying HSRP 669
Summary 675
Exam Essentials 675
Written Lab 16 676
Review Questions 677
Chapter 17 Enhanced IGRP 681
EIGRP Features and Operations 682
Neighbor Discovery 683
Reliable Transport Protocol (RTP) 688
Diffusing Update Algorithm (DUAL) 689
Route Discovery and Maintenance 689
Configuring EIGRP 690
VLSM Support and Summarization 693
Controlling EIGRP Traffic 696
Split Horizon 707
Verifying and Troubleshooting EIGRP 709
Troubleshooting Example with EIGRP 715
Simple Troubleshooting EIGRP for the CCNA 725
EIGRPv6 727
Summary 732
Exam Essentials 733
Written Lab 17 733
Hands-on Labs 734
Hands-on Lab 17.1: Configuring and Verifying EIGRP 734
Hands-on Lab 17.2: Configuring and Verifying EIGRPv6 735
Review Questions 737
Chapter 18 Open Shortest Path First (OSPF) 745
Open Shortest Path First (OSPF) Basics 746
OSPF Terminology 749
OSPF Operation 751
Configuring OSPF 753
Enabling OSPF 753
Configuring OSPF Areas 754
Configuring Our Network with OSPF 757
OSPF and Loopback Interfaces 762
Configuring Loopback Interfaces 763
Verifying OSPF Configuration 765
The show ip ospf Command 766
The show ip ospf database Command 767
The show ip ospf interface Command 768
The show ip ospf neighbor Command 769
The show ip protocols Command 770
Summary 771
Exam Essentials 771
Written Lab 18 772
Hands-on Labs 772
Hands-on Lab 18.1: Enabling the OSPF Process 773
Hands-on Lab 18.2: Configuring OSPF Interfaces 774
Hands-on Lab 18.3: Verifying OSPF Operation 775
Review Questions 776
Chapter 19 Multi-Area OSPF 783
OSPF Scalability 784
Categories of Multi-area Components 786
Adjacency Requirements 786
OSPF Router Roles 787
Link-State Advertisements 788
OSPF Hello Protocol 790
Neighbor States 791
Basic Multi-area Configuration 793
Verifying and Troubleshooting Multi-area OSPF Networks 796
The show ip ospf Command 797
The show ip ospf interface Command 798
The show ip protocols Command 801
The show ip route Command 801
The show ip ospf database Command 802
Troubleshooting OSPF Scenario 804
Simple Troubleshooting OSPF for the CCNA 812
OSPFv3 814
Verifying OSPFv3 816
Summary 819
Exam Essentials 819
Written Lab 19 820
Hands-on Labs 820
Hands-on Lab 19.1: Configuring and Verifying OSPF Multi-Area 821
Hands-on Lab 19.2: Configuring and Verifying OSPFv3 824
Review Questions 826
Chapter 20 Troubleshooting IP, IPv6, and VLANs 831
Troubleshooting IP Network Connectivity 832
Using IP SLA for Troubleshooting 843
Using SPAN for Troubleshooting 845
Configuring and Verifying Extended Access Lists 847
Troubleshooting IPv6 Network Connectivity 850
ICMPv6 850
Troubleshooting IPv6 Extended Access Lists 858
Troubleshooting VLAN Connectivity 862
VLAN Troubleshooting 862
Trunk Troubleshooting 867
Summary 874
Exam Essentials 875
Written Lab 20 875
Review Questions 877
Chapter 21 Wide Area Networks 881
Introduction to Wide Area Networks 882
WAN Topology Options 883
Defining WAN Terms 885
WAN Connection Bandwidth 886
WAN Connection Types 887
WAN Support 888
Cisco Intelligent WAN (IWAN) 891
Cabling the Serial Wide Area Network 894
Serial Transmission 894
Data Terminal Equipment and Data Communication Equipment 895
High-Level Data-Link Control (HDLC) Protocol 896
Point-to-Point Protocol (PPP) 898
Link Control Protocol (LCP) Configuration Options 899
PPP Session Establishment 900
PPP Authentication Methods 901
Configuring PPP on Cisco Routers 901
Configuring PPP Authentication 901
Verifying and Troubleshooting Serial Links 902
Multilink PPP (MLP) 907
PPP Client (PPPoE) 911
Configuring a PPPoE Client 912
Virtual Private Networks 913
Benefits of VPNs 914
Enterprise- and Provider-Managed VPNs 915
Introduction to Cisco IOS IPsec 917
IPsec Transforms 918
GRE Tunnels 919
GRE over IPsec 920
Configuring GRE Tunnels 921
Verifying GRP Tunnels 923
Single-Homed EBGP 925
Protocol Comparison and Overview 926
Configuring and Verifying EBGP 929
Verifying EBGP 931
Summary 934
Exam Essentials 934
Written Lab 21 935
Hands-on Labs 935
Hands-on Lab 21.1: Configuring PPP Encapsulation and Authentication 936
Hands-on Lab 21.2: Configuring and Monitoring HDLC 937
Hands-on Lab 21.3: Configuring a GRE Tunnel 938
Review Questions 941
Chapter 22 Evolution of Intelligent Networks 947
Switch Stacking 948
Cloud Computing and Its Effect on the Enterprise Network 950
Service Models 952
Overview of Network Programmability in Enterprise Network 953
Application Programming Interfaces (APIs) 954
Southbound APIs 955
Northbound APIs 956
Cisco APIC-EM 957
Using APIC-EM for Path Tracing 959
Cisco Intelligent WAN 960
Quality of Service 962
Traffic Characteristics 962
Trust Boundary 964
QoS Mechanisms 965
Classification and Marking 965
Policing, Shaping, and Re-Marking 966
Tools for Managing Congestion 967
Tools for Congestion Avoidance 970
Summary 971
Exam Essentials 971
Written Lab 22 971
Review Questions 973
Appendix A Answers to Written Labs 977
Chapter 1: Internetworking 978
Written Lab 1.1: OSI Questions 978
Written Lab 1.2: Defining the OSI Layers and Devices 979
Written Lab 1.3: Identifying Collision and Broadcast Domains 979
Chapter 2: Ethernet Networking and Data Encapsulation 980
Written Lab 2.1: Binary/Decimal/Hexadecimal Conversion 980
Written Lab 2.2: CSMA/CD Operations 982
Written Lab 2.3: Cabling 982
Written Lab 2.4: Encapsulation 982
Chapter 3: Introduction to TCP/IP 983
Written Lab 3.1: TCP/IP 983
Written Lab 3.2: Mapping Applications to the DoD Model 983
Chapter 4: Easy Subnetting 984
Written Lab 4.1: Written Subnet Practice #1 984
Written Lab 4.2: Written Subnet Practice #2 985
Written Lab 4.3: Written Subnet Practice #3 985
Chapter 5: VLSMs, Summarization and Troubleshooting TCP/IP 986
Chapter 6: Cisco’s Internetworking Operating System (IOS) 986
Written Lab 6: Cisco IOS 986
Chapter 7: Managing a Cisco Internetwork 987
Written Lab 7.1: IOS Management 987
Written Lab 7.2: Router Memory 987
Chapter 8: Managing Cisco Devices 988
Written Lab 8.1: IOS Management 988
Chapter 9: IP Routing 988
Chapter 10: Layer 2 Switching 989
Chapter 11: VLANs and InterVLAN Routing 989
Chapter 12: Security 990
Chapter 13: Network Address Translation (NAT) 991
Chapter 14: Internet Protocol Version 6 (IPv6) 991
Written Lab 14.1: IPv6 Foundation 991
Written Lab 14.2: EUI-64 Format 992
Chapter 15: Enhanced Switched Technologies 992
Written Lab 15 992
Chapter 16: Network Device Management and Security 993
Written Lab 16 993
Chapter 17: Enhanced IGRP 993
Written Lab 17 993
Chapter 18: Open Shortest Path First (OSPF) 994
Written Lab 18 994
Chapter 19: Multi-Area OSPF 994
Written Lab 19 994
Chapter 20: Troubleshooting IP, IPv6, and VLANs 995
Written Lab 20 995
Chapter 21: Wide Area Networks 995
Written Lab 21 995
Chapter 22: Evolution of Intelligent Networks 996
Written Lab 22 996
Appendix B Answers to Review Questions 997
Chapter 1: Internetworking 998
Chapter 2: Ethernet Networking and Data Encapsulation 1000
Chapter 3: Introduction to TCP/IP 1002
Chapter 4: Easy Subnetting 1003
Chapter 5: VLSMs, Summarization, and Troubleshooting TCP/IP 1005
Chapter 6: Cisco’s Internetworking Operating System (IOS) 1007
Chapter 7: Managing a Cisco Internetwork 1009
Chapter 8: Managing Cisco Devices 1010
Chapter 9: IP Routing 1012
Chapter 10: Layer 2 Switching 1013
Chapter 11: VLANs and InterVLAN Routing 1015
Chapter 12: Security 1017
Chapter 13: Network Address Translation (NAT) 1019
Chapter 14: Internet Protocol Version 6 (IPv6) 1020
Chapter 15: Enhanced Switched Technologies 1022
Chapter 16: Network Device Management and Security 1024
Chapter 17: Enhanced IGRP 1025
Chapter 18: Open Shortest Path First (OSPF) 1027
Chapter 19: Multi-Area OSPF 1029
Chapter 20: Troubleshooting IP, IPv6, and VLANs 1031
Chapter 21: Wide Area Networks 1032
Chapter 22: Evolution of Intelligent Networks 1033
Appendix C Disabling and Configuring Network Services 1037
Blocking SNMP Packets 1038
Disabling Echo 1038
Turning off BootP and Auto-Config 1039
Disabling the HTTP Interface 1040
Disabling IP Source Routing 1040
Disabling Proxy ARP 1040
Disabling Redirect Messages 1040
Disabling the Generation of ICMP Unreachable Messages 1041
Disabling Multicast Route Caching 1041
Disabling the Maintenance Operation Protocol (MOP) 1041
Turning Off the X.25 PAD Service 1042
Enabling the Nagle TCP Congestion Algorithm 1042
Logging Every Event 1042
Disabling Cisco Discovery Protocol 1043
Disabling the Default Forwarded UDP Protocols 1043
Cisco’s auto secure 1044
Index 1047
