CCIE Routing and Switching Certification Guide (Exam Certification Guide Series) Book

Foreword xxxi

Introduction xxxii

Part I LAN Switching

Chapter 1 Ethernet Basics 3

“Do I Know This Already?” Quiz 3

Foundation Topics

Ethernet Layer 1: Wiring, Speed, and Duplex 7

RJ-45 Pinouts and Category 5 Wiring 7

Auto-negotiation, Speed, and Duplex 8

CSMA/CD 9

Collision Domains and Switch Buffering 9

Basic Switch Port Configuration 11

Ethernet Layer 2: Framing and Addressing 13

Types of Ethernet Addresses 15

Ethernet Address Formats 16

Protocol Types and the 802.3 Length Field 17

Switching and Bridging Logic 18

SPAN and RSPAN 20

Core Concepts of SPAN and RSPAN 22

Restrictions and Conditions 22

Basic SPAN Configuration 24

Complex SPAN Configuration 24

RSPAN Configuration 25

Foundation Summary

Memory Builders 29

Fill In Key Tables from Memory 29

Definitions 29

Further Reading 29

Chapter 2 Virtual LANs and VLAN Trunking 31

“Do I Know This Already?” Quiz 31

Foundation Topics

Virtual LANs 35

VLAN Configuration 35

Using VLAN Database Mode to Create VLANs 36

Using Configuration Mode to Put Interfaces into VLANs 38

Using Configuration Mode to Create VLANs 39

Private VLANs 40

VLAN Trunking Protocol 42

VTP Process and Revision Numbers 43

VTP Configuration 44

Normal-Range and Extended-Range VLANs 46

Storing VLAN Configuration 47

VLAN Trunking: ISL and 802.1Q 48

ISL and 802.1Q Concepts 48

ISL and 802.1Q Configuration 49

Allowed, Active, and Pruned VLANs 52

Trunk Configuration Compatibility 52

Configuring Trunking on Routers 53

802.1Q-in-Q Tunneling 55

Configuring PPPoE 56

Foundation Summary

Memory Builders 60

Fill In Key Tables from Memory 61

Definitions 61

Further Reading 61

Chapter 3 Spanning Tree Protocol 63

“Do I Know This Already?” Quiz 63

Foundation Topics

802.1d Spanning Tree Protocol 67

Choosing Which Ports Forward: Choosing Root

Ports and Designated Ports 67

Electing a Root Switch 67

Determining the Root Port 69

Determining the Designated Port 70

Converging to a New STP Topology 71

Topology Change Notification and Updating the CAM 72

Transitioning from Blocking to Forwarding 73

Per-VLAN Spanning Tree and STP over Trunks 74

STP Configuration and Analysis 76

Optimizing Spanning Tree 79

PortFast, UplinkFast, and BackboneFast 79

PortFast 80

UplinkFast 80

BackboneFast 81

PortFast, UplinkFast, and BackboneFast Configuration 81

PortChannels 82

Load Balancing Across PortChannels 82

PortChannel Discovery and Configuration 83

Rapid Spanning Tree Protocol 84

Rapid Per-VLAN Spanning Tree Plus (RPVST+) 86

Multiple Spanning Trees: IEEE 802.1s 87

Protecting STP 88

Root Guard and BPDU Guard: Protecting Access Ports 89

UDLD and Loop Guard: Protecting Trunks 89

Troubleshooting Complex Layer 2 Issues 91

Layer 2 Troubleshooting Process 91

Layer 2 Protocol Troubleshooting and Commands 92

Troubleshooting Using Basic Interface Statistics 92

Troubleshooting Spanning Tree Protocol 95

Troubleshooting Trunking 95

Troubleshooting VTP 96

Troubleshooting EtherChannels 98

Approaches to Resolving Layer 2 Issues 100

Foundation Summary

Memory Builders 103

Fill in Key Tables from Memory 103

Definitions 103

Further Reading 103

Part II IP

Chapter 4 P Addressing 105

“Do I Know This Already?” Quiz 105

Foundation Topics

IP Addressing and Subnetting 108

IP Addressing and Subnetting Review 108

Subnetting a Classful Network Number 109

Comments on Classless Addressing 111

Subnetting Math 111

Dissecting the Component Parts of an IP Address 111

Finding Subnet Numbers and Valid Range of IP Addresses–Binary 112

Decimal Shortcuts to Find the Subnet Number and Valid Range of IP

Addresses 113

Determining All Subnets of a Network–Binary 116

Determining All Subnets of a Network–Decimal 118

VLSM Subnet Allocation 119

Route Summarization Concepts 121

Finding Inclusive Summary Routes–Binary 122

Finding Inclusive Summary Routes–Decimal 123

Finding Exclusive Summary Routes–Binary 124

CIDR, Private Addresses, and NAT 125

Classless Interdomain Routing 125

Private Addressing 127

Network Address Translation 127

Static NAT 128

Dynamic NAT Without PAT 130

Overloading NAT with Port Address Translation 131

Dynamic NAT and PAT Configuration 132

Foundation Summary

Memory Builders 138

Fill in Key Tables from Memory 138

Definitions 139

Further Reading 139

Chapter 5 IP Services 141

“Do I Know This Already?” Quiz 141

Foundation Topics

ARP, Proxy ARP, Reverse ARP, BOOTP, and DHCP 146

ARP and Proxy ARP 146

RARP, BOOTP, and DHCP 147

DHCP 148

HSRP, VRRP, and GLBP 150

Network Time Protocol 154

SNMP 155

SNMP Protocol Messages 157

SNMP MIBs 158

SNMP Security 159

Syslog 159

Web Cache Communication Protocol 160

Implementing the Cisco IOS IP Service Level Agreement (IP SLA) Feature 163

Implementing NetFlow 165

Implementing Router IP Traffic Export 166

Implementing Cisco IOS Embedded Event Manager 167

Implementing Remote Monitoring 169

Implementing and Using FTP on a Router 170

Implementing a TFTP Server on a Router 171

Implementing Secure Copy Protocol 171

Implementing HTTP and HTTPS Access 172

Implementing Telnet Access 172

Implementing SSH Access 173

Foundation Summary

Memory Builders 179

Fill In Key Tables from Memory 179

Definitions 179

Further Reading 179

Part III IP Routing

Chapter 6 Forwarding (Routing) 181

“Do I Know This Already?” Quiz 181

Foundation Topics

IP Forwarding 186

Process Switching, Fast Switching, and Cisco Express Forwarding 187

Building Adjacency Information: ARP and Inverse ARP 188

Frame Relay Inverse ARP 189

Static Configuration of Frame Relay Mapping Information 192

Disabling InARP 193

Classless and Classful Routing 194

Multilayer Switching 195

MLS Logic 195

Using Routed Ports and PortChannels with MLS 196

MLS Configuration 197

Policy Routing 201

Optimized Edge Routing and Performance Routing 206

Device Roles in PfR 208

MC High Availability and Failure Considerations 209

PfR Configuration 209

GRE Tunnels 211

Foundation Summary

Memory Builders 215

Fill In Key Tables from Memory 215

Definitions 215

Further Reading 215

Chapter 7 EIGRP 217

“Do I Know This Already?” Quiz 217

Foundation Topics

EIGRP Basics and Steady-State Operation 221

Hellos, Neighbors, and Adjacencies 221

EIGRP Updates 224

The EIGRP Topology Table 226

EIGRP Convergence 228

Input Events and Local Computation 229

Going Active on a Route 231

Stuck-in-Active 233

Limiting Query Scope 234

EIGRP Configuration 234

EIGRP Configuration Example 234

EIGRP Load Balancing 237

EIGRP Authentication 238

EIGRP Automatic Summarization 239

EIGRP Split Horizon 240

EIGRP Route Filtering 240

EIGRP Offset Lists 242

Clearing the IP Routing Table 243

Foundation Summary

Memory Builders 246

Fill In Key Tables from Memory 246

Definitions 246

Further Reading 247

Chapter 8 OSPF 249

“Do I Know This Already?” Quiz 249

Foundation Topics

OSPF Database Exchange 254

OSPF Router IDs 254

Becoming Neighbors, Exchanging Databases, and Becoming Adjacent 255

Becoming Neighbors: The Hello Process 257

Flooding LSA Headers to Neighbors 258

Database Descriptor Exchange: Master/Slave Relationship 259

Requesting, Getting, and Acknowledging LSAs 259

Designated Routers on LANs 260

Designated Router Optimization on LANs 260

DR Election on LANs 262

Designated Routers on WANs and OSPF Network Types 263

Caveats Regarding OSPF Network Types over NBMA Networks 264

Example of OSPF Network Types and NBMA 265

SPF Calculation 268

Steady-State Operation 269

OSPF Design and LSAs 269

OSPF Design Terms 270

OSPF Path Selection Process 271

LSA Types and Network Types 271

LSA Types 1 and 2 272

LSA Type 3 and Inter-Area Costs 275

Removing Routes Advertised by Type 3 LSAs 278

LSA Types 4 and 5, and External Route Types 1 and 2 278

OSPF Design in Light of LSA Types 280

Stubby Areas 281

Graceful Restart 284

OSPF Path Choices That Do Not Use Cost 285

Choosing the Best Type of Path 285

Best-Path Side Effects of ABR Loop Prevention 286

OSPF Configuration 288

OSPF Costs and Clearing the OSPF Process 290

Alternatives to the OSPF Network Command 292

OSPF Filtering 293

Filtering Routes Using the distribute-list Command 293

OSPF ABR LSA Type 3 Filtering 295

Filtering Type 3 LSAs with the area range Command 296

Virtual Link Configuration 296

Configuring OSPF Authentication 298

OSPF Stub Router Configuration 301

Foundation Summary

Memory Builders 306

Fill In Key Tables from Memory 307

Definitions 307

Further Reading 307

Chapter 9 IGP Route Redistribution, Route Summarization, Default Routing, and

Troubleshooting 309

“Do I Know This Already?” Quiz 309

Foundation Topics

Route Maps, Prefix Lists, and Administrative Distance 314

Configuring Route Maps with the route-map Command 314

Route Map match Commands for Route Redistribution 316

Route Map set Commands for Route Redistribution 317

IP Prefix Lists 318

Administrative Distance 320

Route Redistribution 321

Mechanics of the redistribute Command 321

Redistribution Using Default Settings 322

Setting Metrics, Metric Types, and Tags 325

Redistributing a Subset of Routes Using a Route Map 326

Mutual Redistribution at Multiple Routers 330

Preventing Suboptimal Routes by Setting the Administrative Distance 332

Preventing Suboptimal Routes by Using Route Tags 335

Using Metrics and Metric Types to Influence Redistributed Routes 337

Route Summarization 339

EIGRP Route Summarization 341

OSPF Route Summarization 341

Default Routes 342

Using Static Routes to 0.0.0.0, with redistribute static 344

Using the default-information originate Command 345

Using the ip default-network Command 346

Using Route Summarization to Create Default Routes 347

Troubleshooting Complex Layer 3 Issues 349

Layer 3 Troubleshooting Process 349

Layer 3 Protocol Troubleshooting and Commands 351

IP Routing Processes 352

Approaches to Resolving Layer 3 Issues 359

Foundation Summary

Memory Builders 363

Fill In Key Tables from Memory 363

Definitions 363

Further Reading 363

Chapter 10 Fundamentals of BGP Operations 365

“Do I Know This Already?” Quiz 365

Foundation Topics

Building BGP Neighbor Relationships 371

Internal BGP Neighbors 372

External BGP Neighbors 375

Checks Before Becoming BGP Neighbors 376

BGP Messages and Neighbor States 378

BGP Message Types 378

Purposefully Resetting BGP Peer Connections 379

Building the BGP Table 380

Injecting Routes/Prefixes into the BGP Table 380

BGP network Command 380

Redistributing from an IGP, Static, or Connected Route 383

Impact of Auto-Summary on Redistributed Routes and the network

Command 385

Manual Summaries and the AS_PATH Path Attribute 388

Adding Default Routes to BGP 391

ORIGIN Path Attribute 392

Advertising BGP Routes to Neighbors 393

BGP Update Message 393

Determining the Contents of Updates 394

Example: Impact of the Decision Process and NEXT_HOP on BGP Updates 396

Summary of Rules for Routes Advertised in BGP Updates 402

Building the IP Routing Table 402

Adding eBGP Routes to the IP Routing Table 402

Backdoor Routes 403

Adding iBGP Routes to the IP Routing Table 404

Using Sync and Redistributing Routes 406

Disabling Sync and Using BGP on All Routers in an AS 408

Confederations 409

Configuring Confederations 411

Route Reflectors 414

Foundation Summary

Memory Builders 424

Fill In Key Tables from Memory 424

Definitions 424

Further Reading 425

Chapter 11 BGP Routing Policies 427

“Do I Know This Already?” Quiz 427

Foundation Topics

Route Filtering and Route Summarization 433

Filtering BGP Updates Based on NLRI 434

Route Map Rules for NLRI Filtering 437

Soft Reconfiguration 438

Comparing BGP Prefix Lists, Distribute Lists, and Route Maps 438

Filtering Subnets of a Summary Using the aggregate-address Command 439

Filtering BGP Updates by Matching the AS_PATH PA 440

The BGP AS_PATH and AS_PATH Segment Types 441

Using Regular Expressions to Match AS_PATH 443

Example: Matching AS_PATHs Using AS_PATH Filters 446

Matching AS_SET and AS_CONFED_SEQ 449

BGP Path Attributes and the BGP Decision Process 452

Generic Terms and Characteristics of BGP PAs 452

The BGP Decision Process 454

Clarifications of the BGP Decision Process 455

Three Final Tiebreaker Steps in the BGP Decision Process 455

Adding Multiple BGP Routes to the IP Routing Table 456

Mnemonics for Memorizing the Decision Process 456

Configuring BGP Policies 458

Background: BGP PAs and Features Used by Routing Policies 458

Step 0: NEXT_HOP Reachable 460

Step 1: Administrative Weight 460

Step 2: Highest Local Preference (LOCAL_PREF) 463

Step 3: Choose Between Locally Injected Routes Based on ORIGIN PA 466

Step 4: Shortest AS_PATH 467

Removing Private ASNs 467

AS_PATH Prepending and Route Aggregation 468

Step 5: Best ORIGIN PA 471

Step 6: Smallest Multi-Exit Discriminator 471

Configuring MED: Single Adjacent AS 473

Configuring MED: Multiple Adjacent Autonomous Systems 474

The Scope of MED 474

Step 7: Prefer Neighbor Type eBGP over iBGP 475

Step 8: Smallest IGP Metric to the NEXT_HOP 475

The maximum-paths Command and BGP Decision Process Tiebreakers 475

Step 9: Lowest BGP Router ID of Advertising Router (with One Exception) 476

Step 10: Lowest Neighbor ID 476

The BGP maximum-paths Command 476

BGP Communities 478

Matching COMMUNITY with Community Lists 482

Removing COMMUNITY Values 483

Filtering NLRI Using Special COMMUNITY Values 484

Foundation Summary 486

Memory Builders 490

Fill In Key Tables from Memory 490

Definitions 490

Further Reading 490

Part IV QoS

Chapter 12 Classification and Marking 493

“Do I Know This Already?” Quiz 493

Foundation Topics

Fields That Can Be Marked for QoS Purposes 497

IP Precedence and DSCP Compared 497

DSCP Settings and Terminology 498

Class Selector PHB and DSCP Values 499

Assured Forwarding PHB and DSCP Values 499

Expedited Forwarding PHB and DSCP Values 500

Non-IP Header Marking Fields 501

Ethernet LAN Class of Service 501

WAN Marking Fields 501

Locations for Marking and Matching 502

Cisco Modular QoS CLI 503

Mechanics of MQC 504

Classification Using Class Maps 505

Using Multiple match Commands 506

Classification Using NBAR 507

Classification and Marking Tools 508

Class-Based Marking (CB Marking) Configuration 508

CB Marking Example 509

CB Marking of CoS and DSCP 513

Network-Based Application Recognition 515

CB Marking Design Choices 516

Marking Using Policers 517

QoS Pre-Classification 518

Policy Routing for Marking 519

AutoQoS 519

AutoQoS for VoIP 520

AutoQos VoIP on Switches 520

AutoQoS VoIP on Routers 521

Verifying AutoQoS VoIP 522

AutoQoS for the Enterprise 522

Discovering Traffic for AutoQoS Enterprise 522

Generating the AutoQoS Configuration 523

Verifying AutoQos for the Enterprise 523

Foundation Summary 524

Memory Builders 526

Fill In Key Tables from Memory 526

Definitions 526

Further Reading 527

Chapter 13 Congestion Management and Avoidance 529

“Do I Know This Already?” Quiz 529

Cisco Router Queuing Concepts 533

Software Queues and Hardware Queues 533

Queuing on Interfaces Versus Subinterfaces and Virtual Circuits 534

Comparing Queuing Tools 534

Queuing Tools: CBWFQ and LLQ 535

CBWFQ Basic Features and Configuration 536

Defining and Limiting CBWFQ Bandwidth 538

Low-Latency Queuing 541

Defining and Limiting LLQ Bandwidth 543

LLQ with More Than One Priority Queue 545

Miscellaneous CBWFQ/LLQ Topics 545

Queuing Summary 546

Weighted Random Early Detection 546

How WRED Weights Packets 548

WRED Configuration 549

Modified Deficit Round-Robin 550

LAN Switch Congestion Management and Avoidance 552

Cisco Switch Ingress Queueing 553

Creating a Priority Queue 553

Cisco 3560 Congestion Avoidance 555

Cisco 3560 Switch Egress Queuing 556

Resource Reservation Protocol (RSVP) 559

RSVP Process Overview 560

Configuring RSVP 562

Using RSVP for Voice Calls 563

Foundation Summary 565

Memory Builders 565

Fill In Key Tables from Memory 565

Definitions 565

Further Reading 565

Chapter 14 Shaping, Policing, and Link Fragmentation 567

“Do I Know This Already?” Quiz 567

Foundation Topics 572

Traffic-Shaping Concepts 572

Shaping Terminology 572

Shaping with an Excess Burst 574

Underlying Mechanics of Shaping 574

Traffic-Shaping Adaptation on Frame Relay Networks 576

Generic Traffic Shaping 576

Class-Based Shaping 578

Tuning Shaping for Voice Using LLQ and a Small Tc 580

Configuring Shaping by Bandwidth Percent 583

CB Shaping to a Peak Rate 584

Adaptive Shaping 584

Frame Relay Traffic Shaping 584

FRTS Configuration Using the traffic-rate Command 586

Setting FRTS Parameters Explicitly 587

FRTS Configuration Using LLQ 588

FRTS Adaptive Shaping 590

FRTS with MQC 590

Policing Concepts and Configuration 590

CB Policing Concepts 591

Single-Rate, Two-Color Policing (One Bucket) 591

Single-Rate, Three-Color Policer (Two Buckets) 592

Two-Rate, Three-Color Policer (Two Buckets) 593

Class-Based Policing Configuration 595

Single-Rate, Three-Color Policing of All Traffic 595

Policing a Subset of the Traffic 596

CB Policing Defaults for Bc and Be 597

Configuring Dual-Rate Policing 597

Multi-Action Policing 597

Policing by Percentage 598

Committed Access Rate 599

QoS Troubleshooting and Commands 601

Troubleshooting Slow Application Response 602

Troubleshooting Voice and Video Problems 603

Other QoS Troubleshooting Tips 604

Approaches to Resolving QoS Issues 605

Foundation Summary 606

Memory Builders 608

Fill In Key Tables from Memory 608

Definitions 608

Further Reading 609

Part V Wide-Area Networks

Chapter 15 Wide-Area Networks 611

“Do I Know This Already?” Quiz 611

Foundation Topics 614

Point-to-Point Protocol 614

PPP Link Control Protocol 615

Basic LCP/PPP Configuration 615

Multilink PPP 617

MLP Link Fragmentation and Interleaving 619

PPP Compression 620

PPP Layer 2 Payload Compression 621

Header Compression 621

Frame Relay Concepts 622

Frame Relay Data Link Connection Identifiers 623

Local Management Interface 624

Frame Relay Headers and Encapsulation 625

Frame Relay Congestion: DE, BECN, and FECN 626

Adaptive Shaping, FECN, and BECN 627

Discard Eligibility Bit 628

Frame Relay Configuration 628

Frame Relay Configuration Basics 629

Frame Relay Payload Compression 632

Frame Relay Fragmentation 634

Frame Relay LFI Using Multilink PPP (MLP) 636

Foundation Summary 638

Memory Builders 641

Fill In Key Tables from Memory 641

Definitions 641

Part VI IP Multicast

Chapter 16 Introduction to IP Multicasting 643

“Do I Know This Already?” Quiz 643

Foundation Topics 646

Why Do You Need Multicasting? 646

Problems with Unicast and Broadcast Methods 647

How Multicasting Provides a Scalable and Manageable Solution 649

Multicast IP Addresses 652

Multicast Address Range and Structure 652

Well-Known Multicast Addresses 652

Multicast