JNCIA Juniper™ Networks Certified Internet Associate

Study Guide

by Joseph M. Soricelli with John L. Hammond, Galina Diker Pildush, Thomas E. Van Meter, and Todd M. Warble

This book was originally developed by Juniper Networks Inc. in conjunction with Sybex Inc. It is being offered in electronic format because the original book (ISBN: 0-7821-4071-8) is now out of print. Every effort has been made to remove the original publisher's name and references to the original bound book and its accompanying CD. The original paper book may still be available in used book stores or by contacting, John Wiley & Sons, Publishers. www.wiley.com.

Copyright © 2003-6 by Juniper Networks Inc. All rights reserved.

This publication may be used in assisting students to prepare for a Juniper JNCIA exam but Juniper Networks Inc. cannot warrant that use of this publication will ensure passing the relevant exam.

Contents at a Glance

Introduction xvii

Assessment Test

xxxiii

Chapter 1

The Components of a Juniper Networks Router 1

Chapter 2

Interfaces 61

Chapter 3

Protocol-Independent Routing 107

Chapter 4

Routing Policy 149

Chapter 5

The Routing Information Protocol (RIP) 195

Chapter 6

Open Shortest Path First (OSPF) 229

Chapter 7

Intermediate System to Intermediate System (IS-IS) 275

Chapter 8

Border Gateway Protocol (BGP) 321

Chapter 9

Multicast 373

Chapter 10

Firewall Filters 429

Chapter 11

Multiprotocol Label Switching (MPLS) 473

Glossary

533

Index 569

Contents

Introduction xvii

Assessment Test xxxiii

Chapter 1 The Components of a Juniper Networks Router 1

Juniper Networks Router Design 2 Routing Engine Overview 3 Packet Forwarding Engine Overview 4

Routing Engine Components 6 Software Architecture 6 Command-Line Interface 13 Manipulating Files on the Router 44 Routing Engine Redundancy 46

Packet Forwarding Engine Components 47 Embedded OS Software 47 Application-Specific Integrated Circuits 47 Packet Flow 49

Summary 52 Exam Essentials 52 Key Terms 54 Review Questions 55 Answers to Review Questions 59

Chapter 2 Interfaces 61

Types of Interfaces 62 Permanent Interfaces 62 Transient Interfaces 63

Interface Naming 63 Interface Naming Structure 64 Interface Naming Examples 67

Interface Properties 68 Physical Properties 68 Logical Properties 70 Disabling or Deactivating an Interface 73

Configuration Examples 74 IP Version 4 75 IPv6 Support 80 IS-IS Support 82 MPLS Support 84

Useful Interface Commands 85

show interfaces extensive

85

Contents

iv

monitor interface

88

monitor traffic

89

show arp

90

ping

90

ping atm

91

traceroute

91 Interface Diagnostic Commands 92

Loopback Testing 93 BERT Testing 96

Summary 98 Exam Essentials 98 Key Terms 99 Review Questions 100 Answers to Review Questions 104

Chapter 3 Protocol-Independent Routing 107

Configured Routes 108 Static Routes 108 Aggregated Routes 116 Generated Routes 121

Martian Routes 126 JUNOS software Implementation 127 Configuration Examples 127

JUNOS software Routing Tables 131 Table

inet.0

131 Table

inet.1

132 Table

inet.2

133 Table

inet.3

133 Table

inet.4

134 Table

inet6.0

134 Table

mpls.0

134 Table

bgp.l3vpn.0

135 Table

bgp.l2vpn.0

135 JUNOS software Preference Values 136 Load Balancing 137 Summary 140 Exam Essentials 140 Key Terms 141 Review Questions 142 Answers to Review Questions 147

Chapter 4 Routing Policy 149

What Is a Routing Policy? 150 The Routing Table 150

v

Contents

Why Modify the Routing Table? 151 Changing the Map 153

Forming a Policy 153 Composing a Routing Policy 153 Match Conditions 157 Actions 169 Default Policy 171

Applying Routing Policies 173 RIP Policy Application 173 Link-State IGP Policy Application 174 BGP Policy Application 174

Useful JUNOS software Commands 176 Configuring Multiple Policies 177

insert

177

rename

178

show route

Options

180 Summary 183 Exam Essentials 184 Key Terms 185 Review Questions 186 Answers to Review Questions 192

Chapter 5 The Routing Information Protocol (RIP) 195

Overview of RIP 196 RIP Features 197

RIP Operations 199 Input Processing 199 Output Processing 201 Stability Features 201 Timers 203 Limitations 205

Packet Types 206 Version 1 Packet Format 207 Version 2 Packet Format 208

RIPv2 Extensions 209 JUNOS software Configuration 210

Minimum RIP Configuration 210 Applying Export Policy 212 Applying Import Policy 214 Modifying the Incoming Metric 215 Modifying the Outgoing Metric 216 Configuring Authentication 216 Controlling Route Preference 217 Configuring Update Messages 218

Contents

vi

Configuring the Number of Route Entries in an Update Message 220

Accepting Packets Whose Reserved Fields Are Nonzero 220 Summary 221 Exam Essentials 221 Key Terms 222 Review Questions 223 Answers to Review Questions 227

Chapter 6 Open Shortest Path First (OSPF) 229

Basic OSPF Operation 230 Link-State Protocol Review 230 Packet Types 232 Forming Adjacencies 238

Evolution of an OSPF Network 242 The Router LSA 242 Broadcast Networks 243 Scaling an OSPF Network 246 Non-OSPF Routes 250 Additional Scaling Techniques 252

OSPF Configuration 255 Single OSPF Area 255 Multiple OSPF Areas 258

JUNOS software Commands 259 Troubleshooting Your Configuration 259 Troubleshooting the Routing Protocol 261

Summary 266 Exam Essentials 267 Key Terms 268 Review Questions 269 Answers to Review Questions 273

Chapter 7 Intermediate System to Intermediate System (IS-IS) 275

Overview of IS-IS 276 Link-State Review 277 IS-IS Levels 278 Addressing 282

Protocol Specifics 284 IS-IS Adjacency States 284 General IS-IS Information Exchange 284 Protocol Data Units 285

Command-Line Interface 298 Configuration Commands 298 Verification and Troubleshooting Commands 303

vii

Contents

Comparison to OSPF 311 Summary 312 Exam Essentials 312 Key Terms 313 Review Questions 314 Answers to Review Questions 318

Chapter 8 Border Gateway Protocol (BGP) 321

Overview of BGP 322 Network Connectivity 322 Policy Control 323 Reliable Transport 324 Routing Table Scalability 325

Theory of Operation 326 Peers 327 Establishing Relationships 332 Message Types 333 Routing Information Bases 337 The Route Selection Process 338 BGP Attributes 339

Juniper Networks Implementation 345 Establishing Peer Relationships 346 Viewing Routing Knowledge 353 Solving Next Hop Reachability 357

Summary 365 Exam Essentials 365 Key Terms 366 Review Questions 367 Answers to Review Questions 371

Chapter 9 Multicast 373

Multicast Overview 374 Unicast Transmissions 375 Broadcast Transmissions 376 Multicast Transmissions 377

Multicast Addressing 377 IP Group Addresses 378 Ethernet Addresses 380

Multicast Forwarding 383 Reverse Path Forwarding 383 Dense-Mode Forwarding 386 Sparse-Mode Forwarding 388

Contents

viii

Multicast Protocols 390 Internet Group Management Protocol 390 Protocol Independent Multicast 393

JUNOS software Commands 403 IGMP Configuration 404 PIM Configuration 406

show pim neighbors

417

show pim join extensive

418

show pim source

418

show multicast rpf

419

show multicast route

420

show route table inet.1

420

show multicast usage

420 Summary 421 Exam Essentials 421 Key Terms 422 Review Questions 423 Answers to Review Questions 427

Chapter 10 Firewall Filters 429

Firewall Filter Overview 430 Implementing a Firewall Filter 431

Writing the Firewall Filter 431 Processing Filters 432 Segmenting Filters 433 The Default Action 434 Match Conditions 434 Actions 446 Applying Firewall Filters 452

Protecting the Routing Engine 453 Rate Policing 455

Rate Limits 455 Filter Policers 456 Interface Policers 458

JUNOS software Commands 459

show firewall

460

show firewall log

460

show log messages

461

clear firewall

462

show interfaces filters

462

show interfaces policers

462

show policer

463

insert

463

rename

464

ix

Contents

Summary 464 Exam Essentials 465 Key Terms 465 Review Questions 466 Answers to Review Questions 470

Chapter 11 Multiprotocol Label Switching (MPLS) 473

The Creation of MPLS 474 The History of Traffic Engineering and MPLS 475

IP Routing 475 ATM and Overlay Networks 476 SONET and MPLS 478

MPLS Operations 480 Terminology 480 Packet Processing 485 Establishing an LSP 486 Signaling Protocols 488

MPLS Implementation 493 Configuring a Static LSP 494 Configuring a Dynamic LSP 500 Altering the RSVP Protocol 510 Routing