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IP Networking
Wendell Odom, CCIE No. 1624
Cisco Press
800 East 96th Street
Indianapolis, IN 46240
iv IP Networking
Contents at a Glance
Introduction xxx
Unit 1: The TCP/IP Model, LANs, WANs, and IP Networks
Chapter 1 The TCP/IP and OSI Networking Models 3
Chapter 2 LAN Fundamentals 29
Chapter 3 WAN Fundamentals 57
Chapter 4 Class A, B, and C Networks 77
Unit 2: TCP/IP Network, Transport, and Application Layers
Chapter 5 Fundamentals of IP Addressing and Routing 93
Chapter 6 Fundamentals of TCP/IP Transport, Applications, and Security 127
Chapter 7 Operating Cisco Routers 159
Unit 3: IP Subnetting and Basic Router Configuration
Chapter 8 IP Subnetting 187
Chapter 9 Subnet Mask Conversion 209
Chapter 10 Analyzing Existing Subnet Masks 221
Chapter 11 Cisco Router Configuration 233
Unit 4: IP Routing with Connected, Static, and RIP-2 Routes
Chapter 12 IP Routing: Static and Connected Routes 273
Chapter 13 Analyzing Existing Subnets 307
Chapter 14 Routing Protocol Concepts and RIP-2 Configuration 333
Unit 5: IP Troubleshooting and EIGRP
Chapter 15 Troubleshooting IP Routing 357
Chapter 16 EIGRP Concepts and Configuration 393
Unit 6: Subnet Design
Chapter 17 Subnet Mask Design 421
Chapter 18 Finding All Subnet IDs 435
Unit 7: Advanced IP Routing Topics and OSPF
Chapter 19 VLSM and Route Summarization 453
Chapter 20 Troubleshooting IP Routing II 477
Chapter 21 OSPF Concepts and Configuration 505
Unit 8: Advanced IP Topics
Chapter 22 Troubleshooting EIGRP and OSPF 541
Chapter 23 IP Version 6 563
Unit 9: LANs
Chapter 24 Ethernet LAN Switch Concepts 599
Chapter 25 Ethernet Switch Configuration 623
Chapter 26 Virtual LANs 643
Unit 10: WANs
Chapter 27 Point-to-Point WANs 689
Chapter 28 Frame Relay Concepts 713
Chapter 29 Frame Relay Configuration 735
Appendixes
Appendix A: Numeric Reference Tables 773
Appendix B: IP Access Control Lists 781
Glossary 811
Index 842
IP Networking
Table of Contents
Introduction xxx
Unit 1: The TCP/IP Model, LANs, WANs, and IP Networks
Chapter 1 The TCP/IP and OSI Networking Models 3
TCP/IP Networking Model 3
The History Leading to TCP/IP 4
Overview of the TCP/IP Networking Model 5
The TCP/IP Application Layer 7
HTTP Overview 7
HTTP Protocol Mechanisms 7
The TCP/IP Transport Layer 8
TCP Error Recovery Basics 9
Same Layer andAdjacent Layer Interactions 10
The TCP/IP Internet Layer 10
Internet Protocol (IP) and the Postal Service 11
Internet Protocol (IP) Addressing Basics 12
IP Routing Basics 13
The TCP/IP Network Access Layer 14
TCP/IP Model and Terminology 16
Comparing the Two TCP/IP Models 16
Data Encapsulation Terminology 16
Names of TCP/IP Messages 17
OSI Networking Model 18
Comparing OSI and TCP/IP 18
Describing Protocols by Referencing the OSI Layers
OSI Layers and Their Functions 20
OSI Layering Concepts and Benefits 21
OSI Encapsulation Terminology 22
Chapter Review 24
Review Key Topics 24
Define Key Terms 24
Answer Review Questions 25
vii
Chapter 2 LAN Fundamentals 29
An Overview of Modern Ethernet LANs 29
A Brief History of Ethernet 32
The Original Ethernet Standards: 10BASE2 and 10BASE5 32
Repeaters 33
Building 10BASE-T Networks with Hubs 34
Ethernet UTP Cabling 35
UTP Cables and RJ-45 Connectors 36
Transmitting Data Using Twisted Pairs 38
UTP Cabling Pinouts for 10BASE-T and 100BASE-TX 38
1000BASE-T Cabling 41
Improving Performance by Using Switches Instead of Hubs 41
Increasing Available Bandwidth Using Switches 43
Doubling Performance by Using Full-Duplex Ethernet 45
Ethernet Layer 1 Summary 46
Ethernet Data-Link Protocols 46
Ethernet Addressing 46
Ethernet Framing 48
Identifying the Data Inside an Ethernet Frame 50
Error Detection 51
Chapter Review 52
Review Key Topics 52
Define Key Terms 52
Answer Review Questions 53
Chapter 3 WAN Fundamentals 57
OSI Layer 1 for Point-to-Point WANs 57
WAN Connections from the Customer Viewpoint 59
WAN Cabling Standards 61
Clock Rates, Synchronization, DCE, and DTE 62
Building a WAN Link in a Lab 63
Link Speeds Offered by Telcos 64
OSI Layer 2 for Point-to-Point WANs 65
HDLC 65
Point-to-Point Protocol 66
Point-to-Point WAN Summary 67
IP Networking
Frame Relay and Packet-Switching Services 68
The Scaling Benefits of Packet Switching 68
Frame Relay Basics 69
Chapter Review 73
Review Key Topics 73
Define Key Terms 73
Answer Review Questions 73
Chapter 4 Class A, B, and C Networks 77
Classful Network Concepts 77
IPv4 Network Classes and Related Facts 77
Actual Class A, B, and C Networks 78
Address Formats 79
Default Masks 80
Number of Hosts per Network 81
Deriving the Network ID and Related Numbers 81
Unusual Network IDs and Network Broadcast Addresses 83
Practice with Classful Networks 84
Practice Deriving Key Facts Based on an IP Address 84
Practice Remembering the Details of Address Classes 85
Additional Practice 86
Chapter Review 87
Review Key Topics 87
Define Key Terms 87
Practice 87
Review Answers to Earlier Practice Problems 87
Answers to Practice Problem 7 88
Answers to Practice Problem 8 89
Answers to Practice Problem 9 89
Answer Review Questions 89
Unit 2: TCP/IP Network, Transport, and Application Layers
Chapter 5 Fundamentals of IP Addressing and Routing 93
Overview of Network Layer Functions 94
Routing (Forwarding) 94
PCl's Logic: Sending Data to a Nearby Router 94
Rl's and R2's Logic: Routing Data Across the Network 95
R3's Logic: Delivering Data to the End Destination 96
ix
Network Layer Interaction with the Data Link Layer 96
IP Packets and the IP Header 96
Network Layer (Layer 3) Addressing 98
Routing Protocols 99
IP Addressing 100
IP Addressing Definitions 100
How IP Addresses Are Grouped 101
Classes of Networks 102
The Actual Class A, B, and C Network Numbers 104
IP Subnetting 105
IP Routing 108
Host Routing 108
Router Forwarding Decisions and the IP Routing Table 110
IP Routing Protocols 112
Network Layer Utilities 114
Address Resolution Protocol and the Domain Name System 115
DNS Name Resolution 115
The ARP Process 116
Address Assignment and DHCP 117
ICMP Echo and the ping Command 119
Chapter Review 120
Review Key Topics 120
Define Key Terms 121
Answer Review Questions 121
Chapter 6 Fundamentals of TCP/IP Transport, Applications, and Security 127
TCP/IP Layer 4 Protocols: TCP and UDP 127
Transmission Control Protocol 128
Multiplexing Using TCP Port Numbers 128
Popular TCP/IP Applications and Application Layer Protocols 132
Error Recovery (Reliability) 133
Flow Control Using Windowing 134
Connection Establishment and Termination 135
Data Segmentation and Ordered Data Transfer 137
User Datagram Protocol 138
TCP/IP Applications 139
QoS Needs and the Impact of TCP/IP Applications 139
x IP Networking
The World Wide Web, HTTP, and SSL 141
Universal Resource Locators 142
Finding the Web Server Using DNS 142
Transferring Files with HTTP 144
Network Security 144
Perspectives on the Sources and Types of Threats 145
Firewalls and the Cisco Adaptive Security Appliance (ASA) 149
Anti-x 151
Intrusion Detection and Prevention 151
Virtual Private Networks (VPN) 152
Chapter Review 154
Review Key Topics 154
Define Key Terms 154
Answer Review Questions 155
Chapter 7 Operating Cisco Routers 159
Installing Cisco Routers 159
Installing Enterprise Routers 160
Cisco Integrated Services Routers 161
Physical Installation 162
Installing Internet Access Routers 163
A SOHO Installation with a Separate Switch, Router, and Cable Modem
163
A SOHO Installation with an Integrated Switch, Router, and DSL
Modem 164
Regarding the SOHO Devices Used in This Book 165
Accessing and Using the Cisco Router CLI 165
Accessing the CLI 165
CLI Accessfrom the Console 166
Accessing the CLI with Telnet and SSH 168
Password Securityfor CLI Access 169
User and Enable (Privileged) Modes 170
CLI Help Features 171
The debug and show Commands 173
Configuring Cisco IOS Software 174
Configuration Submodes and Contexts 174
Storing Router Configuration Files 176
Copying and Erasing Configuration Files 179
Chapter Review 181
xi
Review Key Topics 181
Define Key Terms 181
Review Command References 181
Answer Review Questions 183
Unit 3: IP Subnetting and Basic Router Configuration
Chapter 8 IP Subnetting 187
Analyze Needs 188
Rules About Which Hosts Are in Which Subnet 188
Determining the Number of Subnets 189
Determining the Number of Hosts per Subnet 190
One Size Subnet Fits All—or Not 191
Defining the Size of a Subnet 191
One Size Subnet Fits All 192
Multiple Subnet Sizes (Variable-Length Subnet Masks) 193
This Book: One Size Subnet FitsAll 194
Make Design Choices 194
Choose a Classful Network 194
Public IP Networks 195
Growth Exhausts the Public IP Address Space 196
Private IP Networks 197
Choosing an IP Network During the Design Phase 197
Choose the Mask 198
IP Networks Before Subnetting 198
Borrowing Host Bits to Create Subnet Bits 199
Choosing Enough Subnet and Host Bits 200
Example Design: 172.16.0.0,200 Subnets, and 200 Hosts 201
Masks and Mask Formats 202
Build a List of All Subnets 203
Plan the Implementation 204
Chapter Review 205
Review Key Topics 205
Define Key Terms 205
Answer Review Questions 205
Chapter 9 Subnet Mask Conversion 209
Subnet Mask Conversion 209
The Three Mask Formats 209
Converting Between Binary and Prefix Masks 210
xii IP Networking
Converting Between Binary and DDN Masks 211
Converting Between Prefix and DDN Masks 213
Practice Converting Subnet Masks 214
Practice Problems for This Chapter 214
Additional Practice 215
Chapter Review 216
Review Key Topics 216
Define Key Terms 216
Practice 216
Review Answers to Earlier Practice Problems 216
Answer Review Questions 217
Chapter 10 Analyzing Existing Subnet Masks 221
Defining the Format of IPv4 Addresses 221
Masks Divide the Subnet's Addresses into Two Parts 222
Masks and Class Divide Addresses into Three Parts 222
Classless and Classful Addressing 223
Calculations Based on the IPv4 Address Format 224
Practice Analyzing Subnet Masks 226
Practice Problems for This Chapter 226
Additional Practice 227
Chapter Review 228
Review Key Topics 228
Define Key Terms 228
Practice 228
Review Answers to Earlier Practice Problems 228
Answer Review Questions 230
Chapter 11 Cisco Router Configuration 233
Configuration Features in Common with Switches 233
Securing the Router CLI 233
Configuring Simple Password Security 234
Configuring Usernames and Secure Shell (SSH) 237
Password Encryption 240
The Two Enable Mode Passwords 241
Console and vty Settings 242
Banners 243
History Buffer Commands 244
The logging synchronous and exec-timeout Commands 244
xiii
Configuring Features Specific to Cisco Routers 245
Router Interfaces 245
Interface Status Codes 247
Router Interface IP Addresses 248
Bandwidth and Clock Rate on Serial Interfaces 249
Router Auxiliary (Aux) Port 251
Initial Configuration (Setup Mode) 251
Upgrading Cisco IOS Software and the Cisco IOS Software Boot Process 254
Upgrading a Cisco IOS Software Image into Flash Memory 255
The Cisco IOS Software Boot Sequence 257
The Three Router Operating Systems 259
The Configuration Register 259
How a Router Chooses Which OS to Load 260
The show version Command and Seeing the Configuration Register's
Value 262
Chapter Review 264
Review Key Topics 264
Define Key Terms 264
Review Command References to Check Your Memory 265
Answer Review Questions 268
Unit 4: IP Routing with Connected, Static, and RIP-2 Routes
Chapter 12 IP Routing: Static and Connected Routes 273
IP Routing and Addressing 273
IP Routing 274
The Impact of Addressing and Subnetting on Routing 277
IP Forwarding by Matching the Most Specific Route 279
Routes to Directly Connected Subnets 280
Connected Routes 281
Secondary IP Addressing 284
Supporting Connected Routes to Subnet Zero 286
ISL and 802.1Q Configuration on Routers 287
Static Routes 289
Configuring Static Routes 291
The Extended ping Command 292
Static Default Routes 294
Default Routes Using the ip route Command 295
Default Routes Using the ip default-network Command 296
xiv IP Networking
Default Route Summary 297
Classful and Classless Routing 298
Summary ofthe Use of the Terms Classless and Classful 298
Classless and Classful Routing Compared 299
Chapter Review 302
Review Key Topics 302
Define Key Terms 302
Review Command Reference to Check Your Memory 302
Answer Review Questions 304
Chapter 13 Analyzing Existing Subnets 307
Defining a Subnet 307
An Example with Network 172.16.0.0 and Four Subnets 308
Subnet ID Concepts 309
The Subnet Broadcast Address 310
The Range of Usable Addresses 311
Analyzing Existing Subnets: Binary 311
Finding the Subnet ID—Binary 312
Finding the Subnet Broadcast—Binary 314
Binary Practice Problems 314
A Shortcut for the Binary Process 316
Brief Note About Boolean Math 317
Finding the Range of Addresses 318
Analyzing Existing Subnets: Decimal 318
Analysis with Easy Masks 318
Predictability in the Interesting Octet 319
Finding the Subnet ID: Difficult Masks 321
Resident Subnet Example 1 321
Resident Subnet Example 2 322
Resident SubnetPractice Problems 323
Finding the Subnet Broadcast Address: Difficult Masks 323
Subnet Broadcast Example 1 324
Subnet BroadcastExample 2 324
Subnet Broadcast Address Practice Problems 325
Practice Analyzing Existing Subnets 325
A Choice: To Memorize or to Calculate 325
Practice Problems for This Chapter 326
Additional Practice 326
Chapter Review 327
Review Key Topics 327
XV
Define Key Terms 327
Practice 327
Answers to Earlier Practice Problems 327
Answer Review Questions 330
Chapter 14 Routing Protocol Concepts and RIP-2 Configuration 333
Routing Protocol Overview 333
RIP-2 Basic Concepts 334
Comparing and Contrasting IP Routing Protocols 335
Interior and Exterior Routing Protocols 335
Routing Protocol Types/Algorithms 337
Metrics 337
Autosummarization and Manual Summarization 338
Classless and Classful Routing Protocols 338
Convergence 339
Miscellaneous Comparison Points 339
Summary of Interior Routing Protocols 339
Configuring and Verifying RIP-2 340
RIP-2 Configuration 340
Sample RIP Configuration 341
RIP-2 Verification 342
Interpreting the Output of the show ip route Command 345
Administrative Distance 345
The show ip protocols Command 347
Examining RIP Messages with debug 348
Chapter Review 351
Review Key Topics 351
Define Key Terms 351
Review Command Reference to Check Your Memory 351
Answer Review Questions 353
Unit 5: IP Troubleshooting and EIGRP
Chapter 15 Troubleshooting IP Routing 357
IP Troubleshooting Tips and Tools 357
IP Addressing 358
Avoiding Reserved IP Addresses 358
One Subnet, One Mask, for Each LAN 359
Summary of IP Addressing Tips 360
xvi IP Networking
Host Networking Commands 360
Troubleshooting Host Routing Problems 363
Finding the Matching Route on a Router 365
Troubleshooting Commands 367
The show ip arp Command 367
The traceroute Command 367
Telnet and Suspend 369
A Routing Troubleshooting Scenario 372
Scenario Part A: Tasks and Questions 372
Scenario Part A: Answers 375
Scenario Part B: Analyze Packet/Frame Flow 377
Scenario Part B: Answers 377
Scenario Part B: Question 1 378
Scenario Part B: Question 2 379
Scenario Part B: Question 3 380
Scenario Part B: Question 4 381
Scenario Part B: Question 5 382
Scenario Part B: Question 6 382
Scenario Part B: Question 7 383
Scenario Part C: Analyze Connected Routes 383
Scenario Part C: Answers 384
Chapter Review 386
Review Key Topics 386
Review Command Reference to Check Your Memory 387
Answer Review Questions 388
Chapter 16 EIGRP Concepts and Configuration 393
EIGRP Concepts and Operation 393
EIGRP Neighbors 394
Exchanging EIGRP Topology Information 394
Calculating the Best Routes for the Routing Table 395
Feasible Distance and Reported Distance 397
Caveats with Bandwidth on Serial Links 397
EIGRP Convergence 398
EIGRP Successors and Feasible Successors 398
The Query and Reply Process 400
EIGRP Summary and Comparisons with OSPF 400
EIGRP Configuration and Verification 401
Basic EIGRP Configuration 402
xvii
EIGRP Metrics, Successors, and Feasible Successors 404
Creating and Viewing a Feasible Successor Route 406
Convergence Using the Feasible Successor Route 407
EIGRP Authentication 408
EIGRP Maximum Paths and Variance 411
Tuning the EIGRP Metric Calculation 412
Chapter Review 414
Review Key Topics 414
Define Key Terms 414
Review Command Reference to Check Your Memory 414
Answer Review Questions 417
Unit 6: Subnet Design
Chapter 17 Subnet Mask Design 421
Choosing the Mask(s) to Meet Requirements 421
Review: Choosing the Minimum Number of Subnet and Host Bits 422
No Masks Meet Requirements 423
One Mask Meets Requirements 424
Multiple Masks Meet Requirements 425
FindingAll the Masks: Concepts 425
FindingAll the Masks: Math 426
Choosing the Best Mask 427
The Formal Process 427
Practice Choosing Subnet Masks 428
Practice Problems for This Chapter 429
Additional Practice 429
Chapter Review 430
Review Key Topics 430
Define Key Terms 430
Practice 430
Review Answers to Earlier Practice Problems 430
Answer Review Questions 431
Chapter 18 Finding All Subnet IDs 435
Finding All Subnet IDs 435
The First Subnet ID: The Zero Subnet 435
Finding the Pattern Using the Magic Number 436
A Formal Process, with Less Than 8 Subnet Bits 437
Example 1: Network 172.16.0.0, Mask 255.255.240.0 438
Example 2: Network 192.168.1.0, Mask 255.255.255.224 439
xviii IP Networking
FindingAll Subnets with Exactly 8 Subnet Bits 440
Finding All Subnets with More Than 8 Subnet Bits 441
Process with 9-16 SubnetBits 442
Process with 17 or More Subnet Bits 443
Practice Finding All Subnet IDs 444
Practice Problems for This Chapter 445
Additional Practice 445
Chapter Review 446
Review Key Topics 446
Define Key Terms 446
Review Answers to Earlier Practice Problems 446
Answer, Practice Problem 1 446
Answer, Practice Problem 2 447
Answer, Practice Problem 3 448
Answer Review Questions 449
Unit 7: Advanced IP Routing Topics and OSPF
Chapter 19 VLSM and Route Summarization 453
VLSM 453
Classless and Classful Routing Protocols 454
Overlapping VLSM Subnets 455
Designing a Subnetting Scheme Using VLSM 456
Adding a New Subnet to an Existing Design 459
VLSM Configuration 460
Manual Route Summarization 461
Route Summarization Concepts 461
Route Summarization Strategies 465
Sample "Best" Summary on Seville 466
Sample "Best" Summary on Yosemite 466
Autosummarization and Discontiguous Classful Networks 467
An Example of Autosummarization 468
Discontiguous Classful Networks 469
Autosummarization Support and Configuration 471
Chapter Review 473
Review Key Topics 473
Define Key Terms 473
Review Command Reference to Check Your Memory 473
Answer Review Questions 474
xix
Chapter 20 Troubleshooting IP Routing II 477
The ping and traceroute Commands 477
Internet Control Message Protocol (ICMP) 477
The ping Command and the ICMP Echo Request and Echo Reply 478
The Destination Unreachable ICMP Message 478
The Redirect ICMP Message 481
The ICMP Time Exceeded Message 481
The traceroute Command 482
Troubleshooting the Packet Forwarding Process 485
Isolating IP Routing Problems Related to Hosts 485
Isolating IP Routing Problems Related to Routers 486
Troubleshooting Scenario 1: Forward Route Problem 488
Troubleshooting Scenario 2: Reverse Route Problem 491
An Alternative Problem Isolation Process for Steps 3, 4, and 5 493
Troubleshooting Tools and Tips 494
Host Routing Tools and Perspectives 494
show ip route Reference 495
Interface Status 496
VLSM Issues 496
Recognizing When VLSM Is Used 497
Configuring Overlapping VLSM Subnets 497
Symptoms with Overlapping Subnets 499
VLSM Troubleshooting Summary 500
Discontiguous Networks and Autosummary 501
Chapter Review 502
Review Key Topics 502
Define Key Terms 502
Chapter 21 OSPF Concepts and Configuration 505
Link-State Routing Protocol Features 505
Building the Same LSDB on Every Router 505
Applying Dijkstra SPF Math to Find the Best Routes 507
Convergence with Link-Stare Protocols 509
Summary and Comparisons to Distance Vector Protocols 509
OSPF Protocols and Operation 510
OSPF Neighbors 511
Identifying OSPF Routers with a Router ID 511
Meeting Neighbors by Saying Hello 511
XX IP Networking
Potential Problems in Becoming a Neighbor 512
Neighbor States 513
OSPF Topology Database Exchange 514
Overview of the OSPF Database Exchange Process 515
Choosing a Designated Router 515
Database Exchange 517
Mamtaining the LSDB While Being Fully Adjacent 517
Summary of Neighbor States 518
Building the IP Routing Table 518
Scaling OSPF Through Hierarchical Design 519
OSPF Areas 520
OSPF Area Design Advantages 522
OSPF Configuration 523
OSPF Single-Area Configuration 523
OSPF Configuration with Multiple Areas 525
Configuring the OSPF Router ID 527
OSPF Hello and Dead Timers 528
OSPF Metrics (Cost) 530
OSPF Authentication 531
OSPF Load Balancing 533
Chapter Review 534
Review Key Topics 534
Define Key Terms 534
Review Command Reference to Check Your Memory 535
Answer Review Questions 537
Unit 8: Advanced IP Topics
Chapter 22 Troubleshooting EIGRP and OSPF 541
Perspectives on Troubleshooting Routing Protocol Problems 541
Interfaces Enabled with a Routing Protocol 542
EIGRP Interface Troubleshooting Example 543
OSPF Interface Troubleshooting Example 548
Neighbor Relationships 550
EIGRP Neighbor Requirements 551
OSPF Neighbor Requirements 553
OSPF Neighbor Example 1 555
OSPF Neighbor Example 2 556
The MTU Matching Requirement 558
xxi
Chapter Review 559
Review Key Topics 559
Review Command Reference to Check Your Memory 559
Chapter 23 IP Version 6 563
Global Unicast Addressing, Routing, and Subnetting 564
Global Route Aggregation for Efficient Routing 565
Conventions for Representing IPv6 Addresses 567
Conventions for Writing IPv6 Prefixes 568
Global Unicast Prefix Assignment Example 570
Subnetting Global Unicast IPv6 Addresses Inside an Enterprise 571
Prefix Terminology 574
IPv6 Protocols and Addressing 575
DHCP for IPv6 575
IPv6 Host Address Assignment 576
The IPv6 Interface ID and EUI-64 Format 576
Static IPv6 Address Configuration 577
Stateless Autoconfiguration and Router Advertisements 578
IPv6 Address Configuration Summary 580
Discovering the Default Router with NDP 580
Learning the IP Address(es) of DNS Servers 580
IPv6 Addresses 581
Unicast IPv6 Addresses 581
Multicast and Other Special IPv6 Addresses 583
Summary of IP Protocols and Addressing 584
Configuring IPv6 Routing and Routing Protocols 585
IPv6 Routing Protocols 585
IPv6 Configuration 586
IPv6 Transition Options 589
IPv4/IPv6 Dual Stacks 589
Tunneling 590
Translating Between IPv4 and IPv6 with NAT-PT 591
Transition Summary 592
Chapter Review 593
Review Key Topics 593
Define Key Terms 593
Review Command Reference to Check Your Memory 594
Answer Review Questions 595
xxii IP Networking
Unit 9: LANs
Chapter 24 Ethernet LAN Switch Concepts 599
LAN Switching Concepts 599
Historical Progression: Hubs, Bridges, and Switches 599
Switching Logic 602
The Forward Versus Filter Decision 603
How Switches Learn MAC Addresses 604
Flooding Frames 605
Avoiding Loops Using Spanning Tree Protocol 606
Internal Processing on Cisco Switches 607
LAN Switching Summary 609
LAN Design Considerations 610
Collision Domains and Broadcast Domains 610
Collision Domains 610
Broadcast Domains 611
The Impactof Collision and BroadcastDomains on LANDesign 612
Virtual LANs (VLAN) 613
Campus LAN Design Terminology 615
Ethernet LAN Media and Cable Lengths 617
Chapter Review 619
Review Key Topics 619
Define Key Terms 619
Answer Review Questions 620
Comparing Cisco Router and Switch Configuration 623
LAN Switch Configuration and Operation 624
Configuring the Switch IP Address 625
Configuring Switch Interfaces 627
Port Security 629
VLAN Configuration 632
Securing Unused Switch Interfaces 635
Chapter Review 636
Review Key Topics 636
Define Key Terms 636
Review Command Reference to Check Your Memory 637
Answer Review Questions 639
Chapter 25 Ethernet Switch Configuration 623
xxiii
Chapter 26 Virtual LANs 643
Virtual LAN Concepts 643
Trunking with ISL and 802.1Q 644
ISL 646
IEEE 802.1Q 646
ISL and 802.1Q Compared 646
IP Subnets and VLANs 648
VLAN Trunking Protocol (VTP) 649
Normal VTP Operation Using VTP Server and Client Modes 650
Three Requirements for VTP to Work Between Two Switches 651
Avoiding VTP by Using VTP Transparent Mode 652
Storing VLAN Configuration 652
VTP Versions 653
VTP Pruning 654
Summary of VTP Features 654
VLAN and VLAN Trunking Configuration and Verification 655
Creating VLANs and Assigning Access VLANs to an Interface 655
VLAN Configuration Example 1: Full VLAN Configuration 656
VLAN Configuration Example 2: Shorter VLAN Configuration 659
VLAN Trunking Configuration 660
Controlling Which VLANs Can Be Supported on a Trunk 665
Trunking to Cisco IP Phones 667
Securing VLANs and Trunking 669
VTP Configuration and Verification 669
Using VTP: Configuring Servers and Clients 669
Caveats When Moving Away from Default VTP Configuration 673
Avoiding VTP: Configuring Transparent Mode 674
Troubleshooting VTP 675
Determining Why VTP Is Not Currently Working 675
Problems When Connecting New Switches and Bringing Up Trunks 680
Avoiding VTP Problems Through Best Practices 682
Chapter Review 683
Review Key Topics 683
Define Key Terms 684
Review Command Reference to Check Your Memory 684
Answer Review Questions 685
xxiv IP Networking
Unit 10: WANs
Chapter 27 Point-to-Point WANs 689
PPP Concepts 689
The PPP Protocol Field 689
PPP Link Control Protocol (LCP) 690
Looped Link Detection 691
Enhanced Error Detection 691
PPPMultilink 692
PPPAuthentication 693
PPP Configuration 694
Basic PPP Configuration 694
CHAP Configuration and Verification 695
Configuring HDLC 696
Troubleshooting Serial Links 699
Troubleshooting Layer 1 Problems 700
Troubleshooting Layer 2 Problems 701
KeepaliveFailure 702
PAP and CHAP Authentication Failure 703
Troubleshooting Layer 3 Problems 704
Chapter Review 707
Review Key Topics 707
Define Key Terms 707
Command Reference to Check Your Memory 707
Answer Review Questions 708
Frame Relay Overview 713
Frame Relay Standards 715
Virtual Circuits 716
LMI and Encapsulation Types 718
Frame Relay Addressing 720
Frame Relay Local Addressing 721
Frame Relay Global Addressing 721
Network Layer Concerns with Frame Relay 724
Frame Relay Layer 3 Addressing: One Subnet Containing All Frame Relay
DTEs 725
Frame Relay Layer 3 Addressing: One Subnet Per VC 725
Frame Relay Layer 3 Addressing: Hybrid Approach 727
Layer 3 Broadcast Handling 728
Chapter 28 Frame Relay Concepts 713
XXV
Chapter Review 730
Review Key Topics 730
Define Key Terms 730
Answer Review Questions 731
Chapter 29 Frame Relay Configuration 735
Frame Relay Configuration and Verification 735
Planning a Frame Relay Configuration 735
A Fully Meshed Network with One IP Subnet 737
Configuring the Encapsulation and LMI 738
Frame Relay Address Mapping 740
Inverse ARP 742
Static Frame Relay Mapping 744
A Partially Meshed Network with One IP Subnet Per VC 745
Assigning a DLCI to a Particular Subinterface 747
Comments About Global and Local Addressing 748
Frame Relay Verification 748
A Partially Meshed Network with Some Fully Meshed Parts 750
Frame Relay Troubleshooting 754
A Suggested Frame Relay Troubleshooting Process 754
Layer 1 Issues on the Access Link (Step 1) 756
Layer 2 Issues on the Access Link (Step 2) 756
PVC Problems and Status (Step 3) 758
Find the Connected Subnetand Outgoing Interface (Steps 3a and 3b) 759
Find the PVCs Assigned to That Interface (Step 3c) 760
Determine Which PVC Is Used to Reach a Particular Neighbor
(Step 3d) 761
PVC Status 762
Subinterface Status 763
Frame Relay Mapping Issues (Step 4) 764
End-to-End Encapsulation (Step 5) 765
Mismatched Subnet Numbers (Step 6) 766
Chapter Review 767
Review Key Topics 767
Review Command Reference to Check Your Memory 767
Answer Review Questions 769
xxvi IP Networking
Appendixes
Appendix A: Numeric Reference Tables 773
Appendix B: IP Access Control Lists 781
Glossary 811
Index 842
