9781587054709

Routing TCP/IP, Volume II: CCIE Professional Development, Second Edition

The definitive guide to Cisco exterior routing protocols and advanced IP routing issues—now completely updated

Praised in its first edition for its readability, breadth, and depth, Routing TCP/IP, Volume II, Second Edition will help you thoroughly understand modern exterior routing protocols and implement them with Cisco routers.

Best-selling author Jeff Doyle offers crucial knowledge for every network professional who must manage routers to support growth and change. You’ll find configuration and troubleshooting lessons that would cost thousands to learn in a classroom, plus up-to-date case studies, examples, exercises, and solutions.

Routing TCP/IP, Volume II, Second Edition covers routing and switching techniques that form the foundation of all Cisco CCIE tracks. Its expert content and CCIE structured review makes it invaluable for anyone pursuing this elite credential.

While its examples focus on Cisco IOS, the book illuminates concepts that are fundamental to virtually all modern networks and routing platforms. Therefore, it serves as an exceptionally practical reference for network designers, administrators, and engineers in any environment.

· Review core inter-domain routing concepts, and discover how exterior routing protocols have evolved

· Master BGP’s modern operational components

· Effectively configure and troubleshoot BGP

· Control path attributes and selection to define better routes

· Take full advantage of NLRI and routing policies

· Provide for load balancing and improved network scalability

· Extend BGP to multiprotocol environments via MP-BGP

· Deploy, configure, manage, troubleshoot, and scale IP multicast routing

· Implement Protocol Independent Multicast (PIM): Dense Mode, Sparse Mode, and Bidirectional

· Operate, configure, and troubleshoot NAT in IPv4-IPv4 (NAT44) and IPv6-IPv4 (NAT64) environments

· Avoid policy errors and other mistakes that damage network performance

This book is part of the CCIE Professional Development series,which offers expert-level instruction on network design, deployment, and support methodologies to help networking professionals manage complex networks and prepare for the CCIE exams.

Category: Networking

Covers: BGP, Multicast, and NAT

Jeff Doyle, CCIE No. 1919, is vice president of research at Fishtech Labs. Specializing in IP routing protocols, SDN/NFV, data center fabrics, MPLS, and IPv6, Jeff has designed or assisted in the design of large-scale IP service provider and enterprise networks in 26 countries over 6 continents. He worked with early IPv6 adopters in Japan, China, and South Korea, and has advised service providers, government agencies, military contractors, equipment manufacturers, and large enterprises on best-practice IPv6 deployment. He now advises large enterprises on evolving data center infrastructures, SDN, and SD-WAN.

Jeff is the author of CCIE Professional Development: Routing TCP/IP, Volumes I and II and OSPF and IS-IS: Choosing an IGP for Large-Scale Networks; a co-author of Software Defined Networking: Anatomy of OpenFlow; and an editor and contributing author of Juniper Networks Routers: The Complete Reference. He also writes for Forbes and blogs for both Network World and Network Computing. Jeff is one of the founders of the Rocky Mountain IPv6 Task Force, is an IPv6 Forum Fellow, and serves on the executive board of the Colorado chapter of the Internet Society (ISOC).

Jeff lives in Westminster, Colorado, with his wife Sara and a Sheltie named Max, the Forrest Gump of the dog world. Jeff and Sara count themselves especially fortunate that their four grown children and a growing herd of grandchildren all live within a few miles.

Introduction xxi

Chapter 1 Inter-Domain Routing Concepts 1

Early Inter-Domain Routing: The Exterior Gateway Protocol (EGP) 1

Origins of EGP 2

Operation of EGP 3

EGP Topology Issues 3

EGP Functions 5

Neighbor Acquisition Protocol 6

Neighbor Reachability Protocol 8

Network Reachability Protocol 10

Shortcomings of EGP 15

The Advent of BGP 16

BGP Basics 17

Autonomous System Types 21

External and Internal BGP 22

Multihoming 29

Transit AS Multihoming 30

Stub AS Multihoming 31

Multihoming and Routing Policies 36

Multihoming Issues: Load Sharing and Load Balancing 36

Multihoming Issues: Traffic Control 37

Multihoming Issues: Provider-Assigned Addressing 40

Classless Inter-Domain Routing 41

A Summarization Summary 41

Classless Routing 43

Summarization: The Good, the Bad, and the Asymmetric 47

CIDR: Reducing Class B Address Space Depletion 50

CIDR: Reducing Routing Table Explosion 50

Managing and Assigning IPv4 Address Blocks 54

CIDR Issues: Multihoming and Provider-Assigned Addresses 56

CIDR Issues: Address Portability 58

CIDR Issues: Provider-Independent Addresses 59

CIDR Issues: Traffic Engineering 60

CIDR Approaches Its Limits 62

IPv6 Comes of Age 66

Routing Table Explosion, Again 66

Looking Ahead 68

Review Questions 69

Chapter 2 Introduction to BGP 71

Who Needs BGP? 71

Connecting to Untrusted Domains 71

Connecting to Multiple External Neighbors 74

Setting Routing Policy 79

BGP Hazards 82

Operation of BGP 84

BGP Message Types 85

Open Message 85

Keepalive Message 86

Update Message 86

Notification Message 87

BGP Finite State Machine 87

Idle State 88

Connect State 89

Active State 89

OpenSent State 89

OpenConfirm State 90

Established State 90

Path Attributes 90

ORIGIN Attribute 92

AS_PATH Attribute 92

NEXT_HOP Attribute 97

Weight 100

BGP Decision Process 100

BGP Message Formats 103

Open Message 104

Update Message 105

Keepalive Message 108

Notification Message 108

Configuring and Troubleshooting BGP Peering 110

Case Study: EBGP Peering 110

Case Study: EBGP Peering over IPv6 114

Case Study: IBGP Peering 118

Case Study: Connected Check and EBGP Multihop 127

Case Study: Managing and Securing BGP Connections 136

Looking Ahead 142

Review Questions 143

Configuration Exercises 144

Troubleshooting Exercises 145

Chapter 3 BGP and NLRI 155

Configuring and Troubleshooting NLRI in BGP 155

Injecting Prefixes with the network Statement 156

Using the network mask Statement 160

Injecting Prefixes with Redistribution 162

NLRI and IBGP 167

Managing Prefixes in an IBGP Topology 168

IBGP and IGP Synchronization 179

Advertising BGP NLRI into the Local AS 182

Redistributing BGP NLRI into the IGP 182

Case Study: Distributing NLRI in a Stub AS with IBGP 184

Distributing NLRI in a Stub AS with Static Routes 193

Advertising a Default Route to a Neighboring AS 196

Advertising Aggregate Routes with BGP 198

Case Study: Aggregation Using Static Routes 199

Aggregation Using the aggregate-address Statement 201

ATOMIC_AGGREGATE and AGGREGATOR Attributes 207

Using AS_SET with Aggregates 210

Looking Ahead 218

Review Questions 218

Configuration Exercises 219

Troubleshooting Exercises 223

Chapter 4 BGP and Routing Policies 237

Policy and the BGP Database 238

IOS BGP Implementation 249

InQ and OutQ 249

IOS BGP Processes 251

NHT, Event, and the Open Processes 256

Table Versions 258

Managing Policy Changes 267

Clearing BGP Sessions 268

Soft Reconfiguraton 269

Route Refresh 274

Route Filtering Techniques 279

Filtering Routes by NLRI 280

Case Study: Using Distribute Lists 280

Route Filtering with Extended ACLs 292

Case Study: Using Prefix Lists 293

Filtering Routes by AS_PATH 304

Regular Expressions 304

Literals and Metacharacters 305

Delineation: Matching the Start and End of Lines 306

Bracketing: Matching a Set of Characters 306

Negating: Matching Everything Except a Set of Characters 306

Wildcard: Matching Any Single Character 307

Alternation: Matching One of a Set of Characters 307

Optional Characters: Matching a Character That May or May Not Be There 307

Repetition: Matching a Number of Repeating Characters 307

Boundaries: Delineating Literals 308

Putting It All Together: A Complex Example 308

Case Study: Using AS-Path Filters 309

Case Study: Setting Policy with Route Maps 314

Filter Processing 322

Influencing the BGP Decision Process 323

Case Study: Administrative Weights 325

Case Study: Using the LOCAL_PREF Attribute 334

Case Study: Using the MULTI_EXIT_DISC Attribute 343

Case Study: Prepending the AS_PATH 366

Case Study: Administrative Distances and Backdoor Routes 372

Controlling Complex Route Maps 379

Continue Clauses 380

Policy Lists 383

Looking Ahead 386

Review Questions 386

Configuration Exercises 388

Troubleshooting Exercises 392

Chapter 5 Scaling BGP 401

Scaling the Configuration 402

Peer Groups 403

Peer Templates 413

Session Templates 414

Policy Templates 419

Communities 425

Well-Known Communities 426

Arbitrary Communities 434

Using the AA:NN Format 443

Expanded Community Lists 445

Adding and Deleting Communities 460

Extended Community Lists 472

Scaling BGP Functions 478

Route Flap Dampening 479

Outbound Route Filters (ORF) 486

Next-Hop Tracking 496

Fast External Fallover 509

Bidirectional Forwarding Detection (BFD) 512

BGP Prefix Independent Convergence (PIC) 523

ADD-PATHS Capability 528

Graceful Restart 538

Maximum Prefixes 540

Tuning BGP CPU 552

Tuning BGP Memory 556

BGP Transport Optimization 563

Optimizing TCP 563

Optimizing BGP Update Generation 568

Optimizing TCP ACK Message Receipt 568

Scaling the BGP Network 569

Private AS Numbers 569

4-Byte AS Numbers 574

IBGP and the N-Squared Problem 575

Confederations 576

Route Reflectors 592

Looking Ahead 606

Review Questions 607

Configuration Exercises 608

Troubleshooting Exercises 612

Chapter 6 Multiprotocol BGP 615

Multiprotocol Extensions to BGP 616

MBGP Support for the IPv6 Address Family 618

Configuring MBGP for IPv6 619

IPv4 and IPv6 Prefixes over an IPv4 TCP Session 620

Upgrading IPv4 BGP Configurations to the Address Family Format 629

IPv4 and IPv6 over an IPv6 TCP Connection 631

Dual Stack MBGP Connection 642

Multihop Dual Stack MBGP Connection 647

Mixed IPv4 and IPv6 Sessions 650

Multiprotocol IBGP 654

Case Study: Multiprotocol Policy Configuration 666

Looking Ahead 705

Review Questions 705

Configuration Exercises 706

Question 1: 707

Troubleshooting Exercises 709

Chapter 7 Introduction to IP Multicast Routing 713

Requirements for IP Multicast 716

IPv4 Multicast Addresses 717

IPv6 Multicast Addresses 721

Group Membership Concepts 724

Joining and Leaving a Group 726

Join Latency 726

Leave Latency 727

Group Maintenance 728

Multiple Routers on a Network 728

Internet Group Management Protocol (IGMP) 729

IGMPv2 Host Functions 730

IGMPv2 Router Functions 731

IGMPv1 733

IGMPv3 735

IGMP Message Format 736

Multicast Listener Discovery (MLD) 742

IGMP/MLD Snooping 745

Cisco Group Management Protocol (CGMP) 749

Multicast Routing Issues 753

Multicast Forwarding 754

Multicast Routing 756

Sparse Versus Dense Topologies 757

Implicit Joins Versus Explicit Joins 758

Source-Based Trees Versus Shared Trees 760

Source-Specific Multicast (SSM) 761

Multicast Scoping 763

TTL Scoping 763

Administrative Scoping 765

Looking Ahead 766

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Routing TCP/IP, Volume II CCIE Professional Development

Routing TCP/IP, Volume II CCIE Professional Development

1587054701

Summary

Author Biography

Table of Contents

Supplemental Materials