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CCNA ICND2 200-101: Troubleshooting IPv4 Routing, Part II
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Table of Contents
Introduction xxviii
Getting Started 3
Part I: LAN Switching 11
Chapter 1 Spanning Tree Protocol Concepts 13
“Do I Know This Already?” Quiz 13
Foundation Topics 16
LAN Switching Review 16
LAN Switch Forwarding Logic 16
Switch Verification 17
Viewing the MAC Address Table 17
Determining the VLAN of a Frame 19
Verifying Trunks 20
Spanning Tree Protocol (IEEE 802.1D) 21
The Need for Spanning Tree 22
What IEEE 802.1D Spanning Tree Does 24
How Spanning Tree Works 25
The STP Bridge ID and Hello BPDU 27
Electing the Root Switch 27
Choosing Each Switch’s Root Port 29
Choosing the Designated Port on Each LAN Segment 31
Influencing and Changing the STP Topology 32
Making Configuration Changes to Influence the STP Topology 32
Reacting to State Changes That Affect the STP Topology 33
How Switches React to Changes with STP 34
Changing Interface States with STP 35
Optional STP Features 36
EtherChannel 37
PortFast 37
BPDU Guard 38
Rapid STP (IEEE 802.1w) 38
Exam Preparation Tasks 40
Chapter 2 Spanning Tree Protocol Implementation 43
“Do I Know This Already?” Quiz 43
Foundation Topics 46
STP Configuration and Verification 46
Setting the STP Mode 47
Connecting STP Concepts to STP Configuration Options 47
Per-VLAN Configuration Settings 47
The Bridge ID and System ID Extension 48
Per-VLAN Port Costs 49
STP Configuration Option Summary 49
Verifying STP Operation 50
Configuring STP Port Costs 53
Configuring Priority to Influence the Root Election 55
Configuring PortFast and BPDU Guard 56
Configuring EtherChannel 58
Configuring a Manual EtherChannel 58
Configuring Dynamic EtherChannels 60
STP Troubleshooting 61
Determining the Root Switch 62
Determining the Root Port on Nonroot Switches 63
STP Tiebreakers When Choosing the Root Port 64
Suggestions for Attacking Root Port Problems on the Exam 65
Determining the Designated Port on Each LAN Segment 66
Suggestions for Attacking Designated Port Problems on the Exam 67
STP Convergence 68
Troubleshooting EtherChannel 68
Incorrect Options on the channel-group Command 68
Configuration Checks Before Adding Interfaces to EtherChannels 70
Exam Preparation Tasks 73
Command Reference to Check Your Memory 73
Chapter 3 Troubleshooting LAN Switching 77
“Do I Know This Already?” Quiz 77
Foundation Topics 78
Generalized Troubleshooting Methodologies 78
Analyzing and Predicting Normal Network Operation 79
Data Plane Analysis 79
Control Plane Analysis 81
Predicting Normal Operations: Summary of the Process 81
Problem Isolation 82
Root Cause Analysis 83
Real World Versus the Exams 84
Troubleshooting the LAN Switching Data Plane 84
An Overview of the Normal LAN Switch Forwarding Process 85
Step 1: Confirm the Network Diagrams Using CDP 86
Step 2: Isolate Interface Problems 88
Interface Status Codes and Reasons for Nonworking States 88
The notconnect State and Cabling Pinouts 90
Determining Switch Interface Speed and Duplex 91
Issues Related to Speed and Duplex 92
Step 3: Isolate Filtering and Port Security Problems 94
Step 4: Isolate VLAN and Trunking Problems 98
Ensuring That the Right Access Interfaces Are in the Right VLANs 98
Access VLANs Not Being Defined or Not Being Active 100
Identify Trunks and VLANs Forwarded on Those Trunks 100
Troubleshooting Examples and Exercises 102
Troubleshooting Example 1: Find Existing LAN Data Plane Problems 103
Step 1: Verify the Accuracy of the Diagram Using CDP 104
Step 2: Check for Interface Problems 105
Step 3: Check for Port Security Problems 107
Step 4: Check for VLAN and VLAN Trunk Problems 109
Troubleshooting Example 2: Predicting LAN Data Plane Behavior 112
PC1 ARP Request (Broadcast) 113
R1 ARP Reply (Unicast) 116
Exam Preparation Tasks 121
Answers to Troubleshooting Example 1 121
Part I Review 124
Part II: IP Version 4 Routing 129
Chapter 4 Troubleshooting IPv4 Routing Part I 131
“Do I Know This Already?” Quiz 131
Foundation Topics 132
Predicting Normal IPv4 Routing Behavior 132
Host IPv4 Routing Logic 132
Routing Logic Used by IPv4 Routers 133
IP Routing Logic on a Single Router 134
IP Routing from Host to Host 135
Building New Data Link Headers Using ARP Information 136
Problem Isolation Using the ping Command 137
Ping Command Basics 138
Strategies and Results When Testing with the ping Command 139
Testing Longer Routes from Near the Source of the Problem 139
Using Extended Ping to Test the Reverse Route 142
Testing LAN Neighbors with Standard Ping 144
Testing LAN Neighbors with Extended Ping 145
Testing WAN Neighbors with Standard Ping 145
Using Ping with Names and with IP Addresses 146
Problem Isolation Using the traceroute Command 147
traceroute Basics 147
How the traceroute Command Works 148
Standard and Extended traceroute 150
Using traceroute to Isolate the Problem to Two Routers 151
Exam Preparation Tasks 154
Chapter 5 Troubleshooting IPv4 Routing Part II 157
“Do I Know This Already?” Quiz 157
Foundation Topics 158
Problems Between the Host and the Default Router 158
Root Causes Based on a Host’s IPv4 Settings 158
Ensure IPv4 Settings Correctly Match 158
Mismatched Masks Impact Route to Reach Subnet 160
Typical Root Causes of DNS Problems 161
Wrong Default Router IP Address Setting 163
Root Causes Based on the Default Router’s Configuration 163
Mismatched VLAN Trunking Configuration with Router on a Stick 163
DHCP Relay Issues 166
Router LAN Interface and LAN Issues 167
Problems with Routing Packets Between Routers 169
IP Forwarding by Matching the Most Specific Route 170
Using show ip route and Subnet Math to Find the Best Route 170
Using show ip route address to Find the Best Route 172
show ip route Reference 172
Routing Problems Caused by Incorrect Addressing Plans 174
Recognizing When VLSM Is Used or Not 174
Overlaps When Not Using VLSM 174
Overlaps When Using VLSM 176
Configuring Overlapping VLSM Subnets 177
Router WAN Interface Status 178
Filtering Packets with Access Lists 178
Exam Preparation Tasks 181
Chapter 6 Creating Redundant First-Hop Routers 183
“Do I Know This Already?” Quiz 183
Foundation Topics 186
FHRP Concepts 186
The Need for Redundancy in Networks 186
The Need for a First Hop Redundancy Protocol 188
The Three Solutions for First-Hop Redundancy 189
HSRP Concepts 190
HSRP Failover 191
HSRP Load Balancing 192
GLBP Concepts 193
FHRP Configuration and Verification 195
Configuring and Verifying HSRP 195
Configuring and Verifying GLBP 198
Exam Preparation Tasks 202
Command Reference to Check Your Memory 202
Chapter 7 Virtual Private Networks 205
“Do I Know This Already?” Quiz 205
Foundation Topics 207
VPN Fundamentals 207
IPsec VPNs 209
SSL VPNs 211
GRE Tunnels 212
GRE Tunnel Concepts 212
Routing over GRE Tunnels 213
GRE Tunnels over the Unsecured Network 214
Configuring GRE Tunnels 216
Verifying a GRE Tunnel 218
Exam Preparation Tasks 221
Command Reference to Check Your Memory 221
Part II Review 224
Part III: IP Version 4 Routing Protocols 229
Chapter 8 Implementing OSPF for IPv4 231
“Do I Know This Already?” Quiz 231
Foundation Topics 234
OSPF Protocols and Operation 234
OSPF Overview 234
Becoming Neighbors and Exchanging the LSDB 235
Agreeing to Become Neighbors 236
Fully Exchanging LSAs with Neighbors 237
Maintaining Neighbors and the LSDB 238
Using Designated Routers on Ethernet Links 239
Scaling OSPF Using Areas 240
OSPF Areas 241
How Areas Reduce SPF Calculation Time 242
OSPF Area Design Advantages 243
Link-State Advertisements 244
Router LSAs Build Most of the Intra-Area Topology 245
Network LSAs Complete the Intra-Area Topology 245
LSAs in a Multi-Area Design 247
Calculating the Best Routes with SPF 248
Administrative Distance 250
OSPF Configuration and Verification 251
OSPFv2 Configuration Overview 251
Multi-Area OSPFv2 Configuration Example 252
Single-Area Configurations 254
Multi-Area Configuration 255
Verifying the Multi-Area Configuration 256
Verifying the Correct Areas on Each Interface on an ABR 256
Verifying Which Router Is DR and BDR 257
Verifying the Number and Type of LSAs 258
Verifying OSPF Routes 259
OSPF Metrics (Cost) 259
Setting the Cost Based on Interface Bandwidth 260
The Need for a Higher Reference Bandwidth 261
OSPF Load Balancing 262
Exam Preparation Tasks 263
Command Reference to Check Your Memory 264
Chapter 9 Understanding EIGRP Concepts 267
“Do I Know This Already?” Quiz 267
Foundation Topics 269
EIGRP and Distance Vector Routing Protocols 269
Introduction to EIGRP 269
Basic Distance Vector Routing Protocol Features 271
The Concept of a Distance and a Vector 271
Full Update Messages and Split Horizon 273
Route Poisoning 275
EIGRP as an Advanced DV Protocol 276
EIGRP Sends Partial Update Messages, As Needed 276
EIGRP Maintains Neighbor Status Using Hello 276
Summary of Interior Routing Protocol Features 277
EIGRP Concepts and Operation 278
EIGRP Neighbors 278
Exchanging EIGRP Topology Information 279
Calculating the Best Routes for the Routing Table 280
The EIGRP Metric Calculation 280
An Example of Calculated EIGRP Metrics 281
Caveats with Bandwidth on Serial Links 283
EIGRP Convergence 284
Feasible Distance and Reported Distance 284
EIGRP Successors and Feasible Successors 285
The Query and Reply Process 287
Exam Preparation Tasks 288
Chapter 10 Implementing EIGRP for IPv4 291
“Do I Know This Already?” Quiz 291
Foundation Topics 294
Core EIGRP Configuration and Verification 294
EIGRP Configuration 294
Configuring EIGRP Using a Wildcard Mask 296
Verifying EIGRP Core Features 296
Finding the Interfaces on Which EIGRP is Enabled 297
Displaying EIGRP Neighbor Status 300
Displaying the IPv4 Routing Table 301
EIGRP Metrics, Successors, and Feasible Successors 302
Viewing the EIGRP Topology Table 303
Finding Successor Routes 305
Finding Feasible Successor Routes 306
Convergence Using the Feasible Successor Route 308
Examining the Metric Components 310
Other EIGRP Configuration Settings 311
Load Balancing Across Multiple EIGRP Routes 311
Tuning the EIGRP Metric Calculation 313
Autosummarization and Discontiguous Classful Networks 314
Automatic Summarization at the Boundary of a Classful Network 314
Discontiguous Classful Networks 315
Exam Preparation Tasks 318
Command Reference to Check Your Memory 318
Chapter 11 Troubleshooting IPv4 Routing Protocols 323
“Do I Know This Already?” Quiz 323
Foundation Topics 324
Perspectives on Troubleshooting Routing Protocol Problems 324
Interfaces Enabled with a Routing Protocol 325
EIGRP Interface Troubleshooting 327
Examining Working EIGRP Interfaces 327
Examining the Problems with EIGRP Interfaces 330
OSPF Interface Troubleshooting 332
Neighbor Relationships 335
EIGRP Neighbor Verification Checks 337
EIGRP Neighbor Troubleshooting Example 338
OSPF Neighbor Troubleshooting 339
Finding Area Mismatches 341
Finding Duplicate OSPF Router IDs 342
Finding OSPF Hello and Dead Timer Mismatches 343
Other OSPF Issues 345
Mismatched OSPF Network Types 345
Mismatched MTU Settings 346
Exam Preparation Tasks 348
Command Reference to Check Your Memory 348
Part III Review 352
Part IV: Wide-Area Networks 357
Chapter 12 Implementing Point-to-Point WANs 359
“Do I Know This Already?” Quiz 359
Foundation Topics 362
Leased Line WANs with HDLC 362
Layer 1 Leased Lines 363
The Physical Components of a Leased Line 363
Leased Lines and the T-Carrier System 365
The Role of the CSU/DSU 367
Building a WAN Link in a Lab 367
Layer 2 Leased Lines with HDLC 368
Configuring HDLC 370
Leased-Line WANs with PPP 373
PPP Concepts 373
PPP Framing 374
PPP Control Protocols 374
PPP Authentication 375
Configuring PPP 376
CHAP Configuration and Verification 377
Troubleshooting Serial Links 378
Troubleshooting Layer 1 Problems 379
Troubleshooting Layer 2 Problems 380
Keepalive Failure 381
PAP and CHAP Authentication Failure 382
Troubleshooting Layer 3 Problems 383
Exam Preparation Tasks 386
Command Reference to Check Your Memory 386
Chapter 13 Understanding Frame Relay Concepts 389
“Do I Know This Already?” Quiz 389
Foundation Topics 392
Frame Relay Overview 392
Virtual Circuits 394
LMI and Encapsulation Types 396
Frame Relay Encapsulation and Framing 397
Frame Relay Addressing 398
Frame Relay Local Addressing 398
Frame Forwarding with One DLCI Field 399
Network Layer Addressing with Frame Relay 401
Frame Relay Layer 3 Addressing: One Subnet Containing All Frame Relay DTEs 401
Frame Relay Layer 3 Addressing: One Subnet Per VC 402
Frame Relay Layer 3 Addressing: Hybrid Approach 404
Exam Preparation Tasks 406
Chapter 14 Implementing Frame Relay 409
“Do I Know This Already?” Quiz 409
Foundation Topics 412
Frame Relay Configuration and Verification 412
Planning a Frame Relay Configuration 412
Configuring Using Physical Interfaces and One IP Subnet 413
Configuring the Encapsulation and LMI 415
Frame Relay Address Mapping 416
Configuring Point-to-Point Subinterfaces 421
Configuring with Multipoint Subinterfaces 426
OSPF Issues on Frame Relay Multipoint and Physical Interfaces 429
Frame Relay Troubleshooting 430
A Suggested Frame Relay Troubleshooting Process 430
Layer 1 Issues on the Access Link (Step 1) 432
Layer 2 Issues on the Access Link (Step 2) 432
PVC Problems and Status (Step 3) 433
Frame Relay Mapping Issues (Step 4) 440
End-to-End Encapsulation (Step 5) 441
Mismatched Subnet Numbers (Step 6) 441
Exam Preparation Tasks 442
Command Reference to Check Your Memory 442
Chapter 15 Identifying Other Types of WANs 445
“Do I Know This Already?” Quiz 445
Foundation Topics 447
Private WANs to Connect Enterprises 447
Leased Lines 447
Frame Relay 449
Ethernet WANs 449
MPLS 451
VSAT 452
Public WANs and Internet Access 453
Internet Access (WAN) Links 453
Dial Access with Modems and ISDN 454
Digital Subscriber Line 456
Cable Internet 457
Mobile Phone Access with 3G/4G 459
PPP over Ethernet 460
Exam Preparation Tasks 463
Part IV Review 464
Part V: IP Version 6 469
Chapter 16 Troubleshooting IPv6 Routing 471
“Do I Know This Already?” Quiz 471
Foundation Topics 472
Normal IPv6 Operation 472
Unicast IPv6 Addresses and IPv6 Subnetting 472
Assigning Addresses to Hosts 475
Stateful DHCPv6 475
Stateless Address Autoconfiguration 476
Router Address and Static Route Configuration 477
Configuring IPv6 Routing and Addresses on Routers 477
IPv6 Static Routes on Routers 478
Verifying IPv6 Connectivity 479
Verifying Connectivity from IPv6 Hosts 479
Verifying IPv6 from Routers 481
Troubleshooting IPv6 483
Pings from the Host Work Only in Some Cases 484
Pings Fail from a Host to Its Default Router 486
Problems Using Any Function That Requires DNS 487
Host Is Missing IPv6 Settings: Stateful DHCP Issues 488
Host Is Missing IPv6 Settings: SLAAC Issues 489
Traceroute Shows Some Hops, But Fails 490
Routing Looks Good, But Traceroute Still Fails 492
Exam Preparation Tasks 494
Command Reference to Check Your Memory 495
Chapter 17 Implementing OSPF for IPv6 499
“Do I Know This Already?” Quiz 499
Foundation Topics 502
OSPFv3 Configuration 502
OSPFv3 ICND1 Configuration Review 502
Example Multi-Area OSPFv3 Configuration 503
Single Area Configuration on the Three Internal Routers 504
Adding Multi-Area Configuration on the Area Border Router 506
Other OSPFv3 Configuration Settings 507
Setting OSPFv3 Interface Cost to Influence Route Selection 507
OSPF Load Balancing 508
Injecting Default Routes 508
OSPF Concepts, Verification, and Troubleshooting 509
OSPFv3 Interfaces 511
Verifying OSPFv3 Interfaces 511
Troubleshooting OSPFv3 Interfaces 512
OSPFv3 Neighbors 513
Verifying OSPFv3 Neighbors 513
Troubleshooting OSPFv3 Neighbors 514
OSPFv3 LSDB and LSAs 517
Verifying OSPFv3 LSAs 517
Troubleshooting OSPFv3 LSAs 519
OSPFv3 Metrics and IPv6 Routes 520
Verifying OSPFv3 Interface Cost and Metrics 520
Troubleshooting IPv6 Routes Added by OSPFv3 523
Exam Preparation Tasks 525
Command Reference to Check Your Memory 525
Chapter 18 Implementing EIGRP for IPv6 529
“Do I Know This Already?” Quiz 529
Foundation Topics 532
EIGRPv6 Configuration 532
EIGRPv6 Configuration Basics 532
EIGRPv6 Configuration Example 533
Other EIGRPv6 Configuration Settings 536
Setting Bandwidth and Delay to Influence EIGRPv6 Route Selection 536
EIGRP Load Balancing 537
EIGRP Timers 538
EIGRPv6 Concepts, Verification, and Troubleshooting 538
EIGRPv6 Interfaces 539
EIGRPv6 Neighbors 541
EIGRPv6 Topology Database 543
EIGRPv6 IPv6 Routes 545
Exam Preparation Tasks 547
Command Reference to Check Your Memory 547
Part V Review 550
Part VI: Network Management 555
Chapter 19 Managing Network Devices 557
“Do I Know This Already?” Quiz 557
Foundation Topics 560
Simple Network Management Protocol 560
Describing SNMP 560
The Management Information Base 562
Configuring SNMP Version 2c 563
SNMP Version 3 565
System Message Logging (Syslog) 566
An Overview of System Message Logging 566
System Message Format 567
System Message Severity Levels 567
Configuring and Verifying Syslog 568
Using a Syslog Server 569
NetFlow 570
An Overview of NetFlow 570
Network Flows 571
Configuring NetFlow 572
Verifying and Using NetFlow 573
The NetFlow Collector 575
Exam Preparation Tasks 576
Chapter 20 Managing IOS Files 579
“Do I Know This Already?” Quiz 579
Foundation Topics 581
Managing Cisco IOS Files 581
Upgrading a Cisco IOS Software Image into Flash Memory 581
The Cisco IOS Software Boot Sequence 584
The Three Router Operating Systems 585
The Configuration Register 586
How a Router Chooses Which OS to Load 586
Recovering If the IOS Does Not Load 588
Verifying the IOS Image Using the show version Command 589
Password Recovery 591
The General Ideas Behind Cisco Password Recovery/Reset 591
A Specific Password Reset Example 592
Managing Configuration Files 595
Configuration File Basics 595
Copying and Erasing Configuration Files 597
Initial Configuration (Setup Mode) 599
Exam Preparation Tasks 601
Command References 601
Chapter 21 Managing IOS Licensing 605
“Do I Know This Already?” Quiz 605
Foundation Topics 607
IOS Packaging 607
IOS Images per Model, Series, and per Software Version/Release 607
Original Packaging: One IOS Image per Feature Set Combination 608
New IOS Packaging: One Universal Image with All Feature Sets 609
IOS Software Activation with Universal Images 609
Managing Software Activation with Cisco License Manager 611
Manually Activating Software Using Licenses 612
Example of Manually Activating a License 614
Showing the Current License Status 614
Adding a Permanent Technology Package License 616
Right-to-Use Licenses 618
Exam Preparation Tasks 621
Command Reference to Check Your Memory 621
Part VI Review 624
Part VII: Final Review 627
Chapter 22 Final Review 629
Advice About the Exam Event 629
Learn the Question Types Using the Cisco Certification Exam Tutorial 629
Think About Your Time Budget Versus Numbers of Questions 630
A Suggested Time-Check Method 631
Miscellaneous Pre-Exam Suggestions 631
Exam-Day Advice 632
Exam Review 632
Practice Subnetting and Other Math-Related Skills 633
Take Practice Exams 635
Practicing Taking the ICND2 Exam 635
Practicing Taking the CCNA Exam 636
Advice on How to Answer Exam Questions 638
Taking Other Practice Exams 639
Find Knowledge Gaps Through Question Review 640
Practice Hands-On CLI Skills 642
Review Mind Maps from Part Review 643
Do Labs 643
Other Study Tasks 643
Final Thoughts 644
Part VIII: Appendixes 647
Appendix A Numeric Reference Tables 649
Appendix B ICND2 Exam Updates 657
Glossary 659
DVD-only Appendixes
Appendix C Answers to the “Do I Know This Already?” Quizzes
Appendix D Memory Tables
Appendix E Memory Tables Answer Key
Appendix F Mind Map Solutions
Appendix G Study Planner
9781587143731 TOC 3/22/2013