Wendell Odom

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About the Author

has worked with networking technology for 15 years. He is currently a Cisco Systems

Senior Systems Engineer in the Atlanta, Georgia office, assigned to several large Cisco customers. Prior to

joining Cisco in 1999, Wendell provided consulting services on large networks as well as training services.

He spent his first eight years in networking working for IBM, helping customers evolve their SNA networks

into multiprotocol networks. Wendell is CCIE #1624, is a Certified Cisco Systems Instructor, is Cisco CIPcertified,

and is a CCNA-WAN. He has taught various Cisco-certified courses, including Introduction to

Cisco Router Configuration (ICRC), Advanced Cisco Router Configuration (ACRC), Cisco SNA for Multiprotocol

Administrators (SNAM), Cisco Channel Interface Processor (CIP), MPLS over Cisco WAN

Switches, and Cisco ATM (CATM). Wendell is one of the first Cisco instructors certified without a probationary

testing period and is the first non-Cisco instructor in the United States to teach Cisco’s SNAM, CIP,

and DLSw courses.

is a Network Consulting Engineer for Cisco Systems in Dallas, Texas. He is a Cisco Certified

Design Professional, MCSE+Internet, and Master CNE. David specializes in large-scale network design and

optimization. He has designed, implemented, and managed networks for numerous Fortune 500 companies

over the past 10 years.

, CCIE #5137 and CCSI, is an instructor and consultant for Chesapeake Network Solutions,

Inc. Tinjin has more than seven years of experience in planning, deploying, and troubleshooting complex

and large-scale IP and multiprotocol networks. Prior to joining Chesapeake, he was the lead network engineer

at Discover Brokerage, where his design and troubleshooting skills minimized downtime and guaranteed

network availability. Discover Brokerage was named the Best Online Broker by

magazine for

the two years that he worked there.

is a data communications trainer. He is the author or tech editor of 12 CBT titles and has

been the author, tech editor, or trainer for eight instructor-led courses. Steve also is beginning a new distance-

learning project as both author and presenter. In addition to those responsibilities, he runs a consulting

company, Esquire Micro Consultants, that specializes in data network design.

, CCIE #3698, is a consultant and instructor currently involved in design, implementation, and

customer training for mixed SNA-IP networks. He is considered to be an expert in the area of mainframe

attached routers. Frank has more than 33 years of networking experience with IBM, GTE, and Skyline Computer

Corp.; during that time, he has worked in field service and support, product planning, education, and

management. In addition, he has developed and taught several courses for the University of Dallas (Telecommunications

MBA program). Frank has a master’s degree in telecommunications from Pace University.

is the president and principal consultant for BJ Consulting, Inc., a small consulting firm that

specializes in networking education. Since starting BJ Consulting, Barb has developed and taught training

courses for Novell’s Master CNE certification, as well as several courses for Cisco System’s Engineering

Education group. Barb stays current on networking technologies by constantly reading published books and

perusing more than 50 industry publications each month. Prior to starting her own company in 1993, Barb

worked for Apple Computer, Tandem Computer, and Tymnet (now part of MCI), where she held positions in

everything from technical support to project management.

Dedication

My wife, Kris, was a great help to me during this latest writing project. While she took no direct role in the

book, everything I do in life is a lot better because the love of my life is with me! Thanks to my parents,

Raymond and Fay, who took care of many things during some health problems I had while writing the book.

And finally, but most importantly, thanks to Jesus Christ, especially for your joy, peace, and protection in the

midst of a tough year.

Acknowledgments

Chris Cleveland, development editor for Cisco Press, is the best in the business! Chris made my job much

easier so that I could concentrate totally on the content. I’d probably refuse to write another book if Chris

wouldn’t be the development editor!

John Kane, executive editor for Cisco Press, provided a great deal of assistance, as usual. John’s frequent

e-mails and conference calls with Cisco’s Worldwide Training organization allowed him to gather the information

needed to guide Cisco Press’s Cisco certification books, and it also allowed me to focus on writing,

instead of sending e-mails and participating in conference calls! Thanks for everything, John.

Many people at Cisco Press have helped make this book a success. Amy Lewis helped greatly by taking care

of many details. Many others worked behind the scenes, and although I never met them, they are appreciated!

Cisco Press spends much more time producing the book than I do to simply write it—they have the

laborious tasks! Thanks to all on the team!

The technical editors deserve most, if not all, of the credit for making the content robust and complete.

There is no question that the book is immensely better after the edit process! While all the editors gave a

great deal of help, each brought some particular strengths to the task. Tinjin, thanks for pointing out topics

for which just a little deeper technical coverage would help to clear up a topic. Steve, thanks for the input

relating to points that come up in the many classes you teach. David, thanks for jumping into the fray in the

middle of the process and adding some great help. Barb, you get the most credit for removing errors from

the book! (Of course, I take full responsibility for any remaining errors.) And, to my old friend Frank,

thanks for all the help and the occasional good-bad joke in your editing comments! (An example: “What’s a

gateway? About 50 pounds!” If you didn’t get it, “gateway” sounds like “gate weigh.”) All the technical editors

were an immense help.

Contents at a Glance

xx

All About the Cisco Certified Network Associate Certification 2

Cisco Internetwork Operating System (IOS) Fundamentals 20

OSI Reference Model & Layered Communication 68

Bridges/Switches and LAN Design 128

Network Protocols 210

Routing 352

Understanding Access List Security 454

WAN Protocols and Design 514

Scenarios for Final Preparation 638

Answers to the “Do I Know This Already?” Quizzes and Q&A Sections 700

Decimal to Hexadecimal and Binary Conversion Table 776

786

Table of Contents

xx

All About the Cisco Certified Network Associate Certification 2

How This Book Can Help You Prepare and Pass the CCNA Exam 4

Overview of Cisco Certifications 4

Exams Required for Certification 6

Other Cisco Certifications 7

What’s on the CCNA Exam 8

Topics on the Exam 9

Recommended Training Path for CCNA 11

How to Use This Book to Pass the Exam 12

I’ve Taken ICND—Now What? 14

I’ve Taken ICRC—Now What? 15

I’ve Taken the Cisco Networking Academy Courses—Now What? 16

I’m New to Internetworking with Cisco, and I Will Not Be Taking the ICND Course—

Now What? 17

I’ve Learned a Lot About CCNA Topics Through Experience, But I Will Not Be Taking

the ICND Course—Now What? 18

Conclusion 18

Cisco Internetwork Operating System (IOS) Fundamentals 20

How to Best Use This Chapter 21

“Do I Know This Already?” Quiz 22

The IOS and Its User Interface 26

Router Components 26

Command-Line Interface 28

Navigating the IOS CLI 30

Configuration Processes and the Configuration File 34

Example Configuration Process 37

Managing Configuration Files 39

Cisco Discovery Protocol (CDP) 45

Managing IOS Images 48

Upgrading an IOS Image into Flash Memory 48

Choosing Which IOS Image to Load 50

Scenario 2-1 61

Questions on Scenario 2-1 62

Scenario 2-2 63

Questions on Scenario 2-2 63

Scenario 2-1 Answers 66

Scenario 2-2 Answers 66

OSI Reference Model & Layered Communication 68

How to Best Use This Chapter 69

“Do I Know This Already?” Quiz 70

The OSI, TCP/IP, and NetWare Protocol Architectures 74

OSI: Origin and Evolution 74

OSI Layers 75

Layering Benefits and Concepts 78

Interaction Between OSI Layers 79

The TCP/IP and NetWare Protocols 86

OSI Transport Layer Functions 87

Connection-Oriented Versus Connectionless Protocols 87

How Error Recovery Is Accomplished 89

Flow Control 91

OSI Data Link Layer Functions 94

Data Link Function 1: Arbitration 95

Data Link Function 2: Addressing 96

Data Link Function 3: Error Detection 98

Data Link Function 4: Identifying the Encapsulated Data 98

Summary: Data Link Functions 102

OSI Network Layer Functions 103

Routing 103

Network Layer (Layer 3) Addressing 107

Scenario 3-1 121

Task 1 for Scenario 3-1 122

Task 2 for Scenario 3-1 123

Task 3 for Scenario 3-1 123

Answers to Task 1 for Scenario 3-1 124

Answers to Task 2 for Scenario 3-1 124

Answers to Task 3 for Scenario 3-1 126

Bridges/Switches and LAN Design 128

How to Best Use This Chapter 129

“Do I Know This Already?” Quiz 130

LAN Overview 135

LAN Addressing 138

LAN Framing 140

Fast Ethernet and Gigabit Ethernet 142

LAN Standards 143

Bridging, Switching, and Spanning Tree 145

Transparent Bridging 145

LAN Switching 148

Comparison of LAN Segmentation Using Bridges, Switches, and Routers 155

Spanning Tree 158

Virtual LANs 171

VLAN Summary 177

LAN Switch Configuration 177

Basic 1900 Switch Configuration 178

Basic VLAN Configuration 187

VLAN Trunking Protocol (VTP) 194

Network Protocols 210

How to Best Use This Chapter 211

“Do I Know This Already?” Quiz 212

TCP/IP Protocols 217

Transmission Control Protocol 217

User Datagram Protocol 224

Address Resolution Protocol 226

Internet Control Message Protocol 227

FTP and TFTP 232

IP Addressing and Subnetting 235

IP Addressing Review 235

Five Ways the Exam Will Test Your IP Addressing Knowledge 244

CIDR, Private Addressing, and NAT 267

IP Configuration 272

Using Secondary Addresses 283

IP Addressing with Frame Relay Subinterfaces 284

MTU and Fragmentation 287

IP Naming Commands and Telnet 288

Default Routes and the ip classless Command 292

IPX Addressing and Routing 296

Internal Networks and Encapsulation Types 299

IPX Configuration 303

Scenario 5-1: IP Addressing and Subnet Calculation 328

Scenario 5-2: IP Subnet Design with a Class B Network 330

Scenario 5-3: IP Subnet Design with a Class C Network 331

Scenario 5-4: IPX Examination 333

Scenario 5-5: IPX Configuration 339

Answers to Scenario 5-1: IP Addressing and Subnet Calculation 340

Answers to Scenario 5-2: IP Subnet Design with a Class B Network 341

Answers to Task 1 for Scenario 5-2 341

Answers to Task 2 for Scenario 5-2 342

Answers to Task 3 for Scenario 5-2 343

Answers to Scenario 5-3: IP Subnet Design with a Class C Network 344

Answers to Task 1 for Scenario 5-3 344

Answers to Task 2 for Scenario 5-3 345

Answers to Task 3 for Scenario 5-3 346

Answers to Scenario 5-4: IPX Examination 347

Answers to Scenario 5-5: IPX Configuration 349

Answers to Task 1 for Scenario 5-5 349

Answers to Task 2 for Scenario 5-5 350

Routing 352

How to Best Use This Chapter 353

“Do I Know This Already?” Quiz 354

Distance Vector Routing Protocols 359

Comparing Routing Protocols 360

Distance Vector Routing 362

Configuration of RIP and IGRP 374

The network Command 375

IGRP Metrics 378

Split Horizon and Infinity 378

RIP-1 and IGRP—No Subnet Masks 383

RIP Version 2 386

Auto Summary and Route Aggregation 389

Multiple Routes to the Same Subnet 395

Troubleshooting Routing and Routing Protocols 396

IPX RIP, SAP, and GNS 403

Service Advertisement Protocol 403

Configuration of IPX 405

Tunneling 409

Tunneling for VPNs 411

Configuring Tunneling 412

Integrated Routing Protocols 413

Scenario 6-1: IP Configuration 1 426

Scenario 6-2: IP Configuration 2 427

Scenario 6-3: IP Addressing and Subnet Derivation 429

Scenario 6-4: IPX Examination 435

Answers to Scenario 6-1: IP Configuration 1 444

Answers to Task 1 for Scenario 6-1 444

Answers to Task 2 for Scenario 6-1 445

Answers to Task 3 for Scenario 6-1 445

Answers to Task 4 for Scenario 6-1 446

Answers to Task 5 for Scenario 6-1 446

Answers to Scenario 6-2: IP Configuration 2 446

Answers to Task 1 for Scenario 6-2 447

Answers to Task 2 for Scenario 6-2 448

Answers to Task 3 for Scenario 6-2 448

Answers to Task 4 for Scenario 6-2 449

Answers to Scenario 6-3: IP Addressing and Subnet Derivation 449

Answers to Task 1 for Scenario 6-3 449

Answers to Task 2 for Scenario 6-3 450

Answers to Task 3 for Scenario 6-3 450

Answers to Scenario 6-4: IPX Examination 450

Answers to Task 1 for Scenario 6-4 450

Answers to Task 2 for Scenario 6-4 452

Answers to Task 3 for Scenario 6-4 453

Answers to Task 4 for Scenario 6-4 453

Understanding Access List Security 454

How to Best Use This Chapter 455

“Do I Know This Already?” Quiz 456

Filtering IP Traffic 460

Standard IP Access Lists 462

Extended IP Access Lists 466

Named IP Access Lists 472

Controlling vty Access with IP Access Lists 475

IP Access List Summary 476

Filtering IPX Traffic and SAPs 476

IPX Packet Filters (Access Lists) 478

Standard IPX Access Lists 479

Extended IPX Access Lists 484

SAP Filters 487

Named IPX Access Lists 490

Scenario 7-1: IP Filtering Sample 1 503

Scenario 7-2: IP Filtering Sample 2 504

Scenario 7-3: IP Filtering Sample 3 504

Scenario 7-4: IPX Filtering 505

Answers to Scenario 7-1: IP Filtering Sample 1 508

Answers to Scenario 7-2: IP Filtering Sample 2 508

Answers to Scenario 7-3: IP Filtering Sample 3 509

Answers to Scenario 7-4: IPX Filtering 510

Answers to Task 1 for Scenario 7-4 510

Answers to Task 2 for Scenario 7-4 511

Answers to Task 3 for Scenario 7-4 512

WAN Protocols and Design 514

How to Best Use This Chapter 515

“Do I Know This Already?” Quiz 516

Point-to-Point Leased Lines 520

HDLC and PPP Configuration 523

WAN Cabling Standards 528

Frame Relay Protocols 529

Frame Relay Features and Terminology 530

LMI and Encapsulation Types 532

DLCI Addressing and Frame Relay Switching 534

Network Layer Concerns with Frame Relay 538

How Address Mapping Works 543

Review: Basic Frame Relay Initialization 549

Compression 549

Frame Relay Configuration 551

Configuring Networks Without Subinterfaces 553

Configuring Networks with Point-to-Point Subinterfaces 555

Configuring Networks with Coexisting Point-to-Point and Multipoint

Subinterfaces 559

Payload Compression Configuration 563

ISDN Protocols and Design 567

ISDN Channels 567

ISDN Protocols 568

ISDN Function Groups and Reference Points 570

Typical Use of ISDN 574

PAP and CHAP 574

Multilink PPP 577

Dial-on-Demand Routing and ISDN Configuration 578

DDR Legacy Concepts and Configuration 580

A Comparison of WAN Options 590

Scenario 8-1: Point-to-Point Verification 608

Scenario 8-2: Frame Relay Verification 612

Scenario 8-3: Point-to-Point Configuration 619

Scenario 8-4: Frame Relay Configuration 620

Scenario 8-5: Frame Relay Configuration Dissection 623

Answers to Scenario 8-1: Point-to-Point Verification 626

Answers to Scenario 8-2: Frame Relay Verification 627

Answers to Scenario 8-3: Point-to-Point Configuration 629

Answers to Scenario 8-4: Frame Relay Configuration 631

Answers to Scenario 8-5: Frame Relay Configuration Dissection 636

Scenarios for Final Preparation 638

How to Best Use This Chapter 640

Scenario 9-1 641

Scenario 9-1, Part A—Planning 641

Solutions to Scenario 9-1, Part A—Planning 644

Scenario 9-1, Part B—Configuration 645

Solutions to Scenario 9-1, Part B—Configuration 646

Scenario 9-1 Part C—Verification and Questions 647

Solutions to Scenario 9-1, Part C—Verification and Questions 656

Scenario 9-2 658

Scenario 9-2, Part A—Planning 658

Solutions to Scenario 9-2, Part A—Planning 660

Scenario 9-2, Part B—Configuration 662

Solutions to Scenario 9-2, Part B—Configuration 662

Scenario 9-2, Part C—Verification and Questions 664

Solutions to Scenario 9-2, Part C—Verification and Questions 673

Scenario 9-3 675

Scenario 9-3, Part A—Planning 675

Solutions to Scenario 9-3, Part A—Planning Answers 678

Scenario 9-3, Part B—Configuration 681

Solutions to Scenario 9-3, Part B—Configuration 681

Scenario 9-3, Part C—Verification and Questions 684

Solutions to Scenario 9-3, Part C—Verification and Questions 696

Answers to the “Do I Know This Already?” Quizzes and Q&A Sections 700

Answers to the Chapter 2 “Do I Know This Already?” Quiz 701

Answers to the Chapter 2 Q&A Section 703

Answers to the Chapter 3 “Do I Know This Already?” Quiz 708

Answers to the Chapter 3 Q&A Section 710

Answers to the Chapter 4 “Do I Know This Already?” Quiz 715

Answers to the Chapter 4 Q&A Section 718

Answers to the Chapter 5 “Do I Know This Already?” Quiz 724

Answers to the Chapter 5 Q&A Section 728

Answers to the Chapter 6 “Do I Know This Already?” Quiz 745

Answers to the Chapter 6 Q&A Section 748

Answers to the Chapter 7 “Do I Know This Already?” Quiz 754

Answers to the Chapter 7 Q&A Section 757

Answers to the Chapter 8 “Do I Know This Already?” Quiz 766

Answers to the Chapter 8 Q&A Section 768

Decimal to Hexadecimal and Binary Conversion Table 776

786

Figure Icons Used in This Book

Throughout the book, you will see the following icons used for networking devices:

Throughout the book, you will see the following icons used for peripherals and other devices.

Throughout the book, you will see the following icons used for networks and network connections.

Introduction: Overview of

Certification and How to Succeed

Professional certifications have been an important part of the computing industry for many years and will

continue to become more important. Many reasons exist for these certifications, but the most popularly cited

reason is that of credibility. All other considerations held equal, the certified employee/consultant/job candidate

is considered more valuable than one who is not.

The most important and somewhat obvious objective of this book is to help you pass the CCNA exam

(640-507). In fact, if the primary objective of this book was different, then the book’s title would be misleading;

however, the methods used in this book to help you pass the CCNA exam are designed to also make

you much more knowledgeable about how to do your job. While this book and the accompanying CD

together have more than 500 questions, the method in which they are used is not to simply make you memorize

as many questions and answers as you possibly can.

One key methodology used in this book is to help you discover the exam topics about which you need more

review, to help you fully understand and remember those details, and to help you prove to yourself that you

have retained your knowledge of those topics. So, this book does not try to help you pass by memorization,

but by helping you truly learn and understand the topics. The CCNA exam is the foundation for many of the

Cisco professional certifications, and it would be a disservice to you if this guide did not help you truly learn

the material. So, this book will help you pass the CCNA exam by using the following methods:

• Helping you discover which test topics you have not mastered

• Providing explanations and information to fill in your knowledge gaps

• Supplying exercises and scenarios that enhance your ability to recall and deduce the answers to test

questions

• Providing practice exercises on the topics and the testing process via test questions on the CD

This book is not designed to be a general networking topics book, although it can be used for that purpose.

This book is intended to tremendously increase your chances of passing the CCNA exam. Although other

objectives can be achieved from using this book, the book is written with one goal in mind: to help you pass

the exam.

So why should you want to pass the CCNA exam? To get a raise. To show your manager you are working

hard to increase your skills. To fulfill a requirement from your manager before he will spend money on

another course. To enhance your résumé. To please your reseller-employer, who needs more certified

employees for a higher discount from Cisco. To prove that you know the topic, if you learned via on-the-job

training (OJT) rather than from taking the prerequisite classes. Or, one of many other reasons.

Others who might want to use this book are those considering skipping Cisco’s Interconnecting Cisco Network

Devices (ICND) course to take Cisco’s Building Scalable Cisco Networks (BSCN) or Building Cisco

Multilayer Switched Networks (BCMSN) courses. If you can answer a high percentage of the questions in

this book, you should be ready for those courses.

The strategy you use for CCNA preparation might be slightly different than strategies used by other readers,

mainly based on the skills, knowledge, and experience you already have obtained. For instance, if you have

attended Cisco’s Interconnecting Cisco Networking Devices (ICND) course, then you will need to take a

slightly different approach compared to someone who has learned Cisco knowledge via on-the-job training.

Chapter 1, “All About the Cisco Certified Network Associate Certification,” includes a strategy that should

closely match your background.

Regardless of the strategy you use or the background you have, the book is designed to help you get to the

point where you can pass the exam with the least amount of time required. For instance, there is no need for

you to practice or read about IP addressing and subnetting if you fully understand it already. However, many

people like to make sure that they truly know a topic and thus read over material that they already know.

Several book features will help you gain the confidence that you need to be convinced that you know some

material already, and to also help you know what topics you need to study more.

Although this book could be read cover-to-cover, it is designed to be flexible and allow you to easily move

between chapters and sections of chapters to cover just the material that you need more work with. Chapter

1 provides an overview of the CCNA certification, and offers some strategies for how to prepare for the

exam. Chapters 2 through 8 are the core chapters and can be covered in any order. If you do intend to read

them all, the order in the book is an excellent sequence to use. Chapter 9, “Scenarios for Final Preparation,”

provides many scenarios that will help you review and refine your knowledge, without giving you a false

sense of preparedness that you would get with simply reviewing a set of multiple-choice questions.

The core chapters, Chapters 2 through 8, cover the following topics:

• The IOS is the software that runs on a variety of Cisco products, particularly in routers and in some

LAN switches. This chapter covers many of the features and functions of the IOS, as well as its

command-line interface (CLI). Also included in this chapter are details about router hardware.

• The OSI reference model is mainly used today for comparison to other protocol architectures. The

purposes and meanings behind the use of a layered model are discussed in this chapter. The features

typically implemented at the various layers also are covered, and example protocols for each layer are

given. Much of this information is conceptual and is not necessarily needed in order to implement

networks, but it is covered on the exam.

Also covered in Chapter 3 are the concepts involved in typical operation of the OSI network and data

link layers. This conceptual discussion is vital to complete understanding of OSI Layer 2 and Layer

3 operation.

• LANs—in particular, the various forms of Ethernet—are covered in this chapter. The logic behind

transparent bridging and LAN switches is also discussed in depth, as is the operation of the Spanning-

Tree Protocol. LAN switch configuration on the 1900 series LAN switch, using its IOS CLI, is

covered as well.

• This chapter discusses TCP/IP and NetWare protocols, as well as their configuration on Cisco routers.

IP addressing is covered in great depth, with many tools to prepare you for questions on the exam.

NetWare initialization flows and encapsulations are detailed as well.

• Routing protocols are used by routers to dynamically learn routing information. This chapter covers

the types of routing protocols, with a detailed look at distance vector routing protocol logic. The

implementation of IP RIP and IGRP, and Novell RIP and SAP, is covered here as well.

• Network security is a very broad subject area. This chapter focuses on the security topics covered on

the CCNA exam—namely access lists. IP standard access lists, both numbered and named, are

discussed as well. Likewise, numbered and named IPX and SAP access lists are described.

• This chapter covers point-to-point serial links as the first type of WAN link and then discusses the

various data link protocols used on point-to-point links, both for concepts and configuration. Frame

Relay is covered in great detail, largely because point-to-point links and Frame Relay are the two

most popular WAN options in routers today. Finally, this chapter covers ISDN protocols and their use

in simple dial-on-demand (DDR) environments.

Additional scenarios in Chapter 9 provide a method of final preparation with more questions and exercises.

Example test questions and the testing engine on the CD allow simulated exams for final practice.

Each of these chapters uses several features to help you make best use of your time in that chapter. The features

are as follows:

•

—Each chapter begins with a quiz that helps you

determine the amount of time you need to spend studying that chapter. The quiz is broken into

subdivisions, called “quizlets,” that correspond to a section of the chapter. Following the directions at

the beginning of each chapter, the “Do I Know This Already?” quiz will direct you to study all or

particular parts of the chapter.

•

—This is the core section of each chapter that explains the protocols, concepts, and

configuration for the topics in the chapter.

•

—Near the end of each chapter, a summary collects the most important tables

and figures from the chapter. The “Foundation Summary” section is designed to help you review the

key concepts in the chapter if you score well on the “Do I Know This Already?” quiz, and they are

excellent tools for last-minute review.

•

—Located at the end of most chapters, as well as in Chapter 9, the scenarios allow a much

more in-depth examination of a network implementation. Rather than posing a simple question

asking for a single fact, the scenarios let you design and build networks (at least on paper) without

the clues inherent in a multiple-choice quiz format.

in the text of the book. You can answer these questions by using the simulated exam feature, or by

using the topical review feature. This is the best tool for helping you prepare for the test-taking

process.

Retention and recall are the two features of human memory most closely related to performance on tests.

This exam preparation guide focuses on increasing both retention and recall of the topics on the exam. The

other human characteristic involved in successfully passing the exam is intelligence; this book does not

address that issue!

Adult retention is typically less than that of children. For example, it is common for 4-year-olds to pick up

basic language skills in a new country faster than their parents. Children retain facts as an end unto itself;

adults typically either need a stronger reason to remember a fact or must have a reason to think about that

fact several times to retain it in memory. For these reasons, a student who attends a typical Cisco course and

retains 50 percent of the material is actually quite an amazing student.

Memory recall is based on connectors to the information that needs to be recalled—the greater the number

of connectors to a piece of information, the better chance and better speed of recall. For example, if the

exam asks what ARP stands for, you automatically add information to the question. You know the topic is

networking because of the nature of the test. You might recall the term “ARP broadcast,” which implies that

ARP is the name of something that flows in a network. Maybe you do not recall all three words in the acronym,

but you recall that it has something to do with addressing. Of course, because the test is multiplechoice,

if only one answer begins with “address,” you have a pretty good guess. Having read the answer

“Address Resolution Protocol,” then you might even have the infamous “aha” experience, in which you are

then sure that your answer is correct (and possibly a brightly lit light bulb is hovering over your head). All

these added facts and assumptions are the connectors that eventually lead your brain to the fact that needs to

be recalled. Of course, recall and retention work together. If you do not retain the knowledge, it will be dif-

ficult to recall it.

This book is designed with features to help you increase retention and recall. It does this in the following

ways:

• By providing succinct and complete methods of helping you decide what you recall easily and what

you do not recall at all.

• By giving references to the exact passages in this book that review those concepts you did not recall

so that you can quickly be reminded about a fact or concept. Repeating information that connects to

another concept helps retention, and describing the same concept in several ways throughout a

chapter increases the number of connectors to the same piece of information.

• By including exercise questions that supply fewer connectors than multiple-choice questions. This

helps you exercise recall and avoids giving you a false sense of confidence, as an exercise with only

multiple-choice questions might do. For example, fill-in-the-blank questions require you to have

better recall than a multiple-choice question.

• By pulling the entire breadth of subject matter together. A separate, larger chapter (Chapter 9)

contains scenarios and several related questions that cover every topic on the exam and gives

you the chance to prove that you have gained mastery over the subject matter. This reduces the

connectors implied by questions residing in a particular chapter and requires you to exercise other

connectors to remember the details.

• Finally, accompanying this book is a CD-ROM that has exam-like, multiple-choice questions. These

are useful for you to practice taking the exam and to get accustomed to the time restrictions imposed

during the exam.

Congratulations! You have made your first step in beginning your journey to joining the

Cisco Career Certifications group of certified professionals. CCNA is the first step into your

journey.

The Cisco Certified Network Associate (CCNA) certification is the most popular

certification among all Cisco certifications. CCNA certification is a prerequisite for several

other Cisco Certifications, which of course adds to its popularity.

The exam itself is a computer-based exam, with multiple choice, fill-in-the-blank, and dragand-

drop style questions. The CCNA exam is delivered by our testing vendor, Sylvan

Prometric, which you can reach at 1-800-829-NETS, or you may register online at

www.2test.com. As we continually update the exams, the duration and number of questions

per exam will vary. When you register for your exam, the registrar will reserve the

appropriate time. You should check with Sylvan Prometric for the exact length of the exam.

Be aware that when you register for the exam, you might be notified of a specific length of

time, and when you actually log in to the testing software at the testing center, you might

find that the testing time is 15 minutes shorter; that’s because Sylvan Prometric expects

some time to be required for getting settled and taking the tutorial on the testing engine.

The CCNA exam is not an easy, read the book and you pass kind of exam. It is surprisingly

hard, but Cisco’s philosophy is that by passing the exam, you fully understand the concepts.

More importantly, Cisco wants to be sure that passing the exam proves that you have the

skills to actually implement the features, not just talk about them. For instance, you can

expect questions that ask for the name of a router command that displays a particular piece

of information—most of us don’t memorize all the types of things displayed by every

command! So, the difficulty helps enhance the value of the CCNA certification, which

ultimately is better for those of us who are getting certified.

Also, in order to ensure the exam proves that you know your stuff, the exam does NOT

allow you to go back and change an answer, as many other exams allow, and as the original

version of the CCNA exam allowed.

Chapter 1: All About the Cisco Certified Network Associate Certification

Although it is a difficult exam, if your time is spent on training, experience, and study, you are

preparing yourself for success. If you don’t prepare adequately, it is more than likely that you

will not pass the first time. The concepts and commands covered on the exam are not secrets

locked in some vault, though—the information is available in many places and forms, including

this book. So, while difficult, passing the exam is certainly attainable with proper training and

preparation.

The first goal for this book came at the request of the Cisco Career Certifications team; they

asked that we build a book that didn’t just help you pass a test, but also for a book that helped

you really understand the concepts and implementation details. (Because Cisco Press is the only

Cisco authorized publisher, we tend to listen to Cisco!) A second goal was to make the content

of the book the most comprehensive coverage of CCNA-related topics available, but without a

lot of coverage of topics not on the exam. The third and ultimate goal is to get you from where

you are today to the point where you can confidently pass the CCNA exam. So, all the book

features, which are outlined in the Introduction, are geared toward helping you discover what

CCNA topics you do know well, what CCNA topics you don’t know well, and what information

and tools you need to fill in the gaps.

One key assumption this book makes is that the perfect audience is made up of people who

either have attended the Interconnecting Cisco Networking Devices class or the Introduction to

Cisco Router Configuration class, or have had similar experience with Cisco switches and

routers. If you are relatively new to Cisco networking and have not taken any classes, do not

despair! You can still use this book, but also should consider either taking the ICND class or

buying the book version of the ICND class from Cisco Press—

. The ICND course, and therefore also the ICND book, are written for an audience of

those who are just starting out in the Cisco world.

Cisco’s main motivation behind the current certification program is to provide a means of

measuring the skills of people working for Cisco Resellers and Certified Partners. Cisco fulfills

only a small portion of its orders via direct sale from Cisco; most times, a Cisco reseller is

involved. Also, Cisco has not attempted to become the primary source for consulting and

implementation services for network deployment using Cisco products; instead, the company

prefers to use partners as much as possible. With that business model, a great need arose to

certify the skill levels of the partner companies.

The Cisco Certified Internetworking Expert (CCIE) program was Cisco’s first foray into

certifications. Introduced in 1994, the CCIE was designed to be one of the most respected,

difficult-to-achieve certifications. To certify, a person must pass a written test (also given at

Overview of Cisco Certifications

Sylvan Prometric centers) and then pass a 2-day hands-on lab test administered by Cisco. Cisco

does not publish numbers on pass/fail rates for CCIE or the other certifications, but rumors have

it that the failure rate on all lab test-takers is more than 50 percent, with failure rate for firsttime

lab-takers at more than 80 percent.

By using the number of employed CCIEs as the guage, certifying resellers and services partners

worked well originally, partly because Cisco had significantly fewer partners than today. Cisco

uses the number of CCIEs on staff as part of the criteria in determining the level of partner status

for the company, which in turn dictates the discount received by the reseller when buying from

Cisco. (If you want a little more insight into reseller certification, look at www.cisco.com/warp/

public/767/chan/ptnrcert-matrix.html.) This practice continues to be a good way for Cisco to

judge the commitment of resellers to hire people with proven Cisco skills, which in turn

improves customer satisfaction—and customer satisfaction is tied to every Cisco executive’s

bonus plan.

The CCIE certification fell short of the goal to help certify resellers and other partners as the

number of partners increased. For instance, there are around 4500 CCIEs worldwide, and about

half that many resellers—and not all the CCIEs work for resellers, of course. More importantly,

many resellers that did not perform services did not need a CCIE on staff except to get a better

discount. Thus, Cisco needed certifications that were less rigorous than CCIE, which would

allow Cisco more granularity in judging the skills on staff at a partner company. So, Cisco

created several additional certifications, with CCNA included. Figure 1-1 shows the CCIE and

career certifications for routing and switching.

Two categories of certifications were developed: one to certify implementation skills, and the

other to certify design skills. Resellers working in a presale environment need more design

skills, whereas services companies need more implementation skills. So, the CCNA and CCNP

provide implementation-oriented certifications, whereas the CCDA and CCDP certifications

provide design-oriented certifications.

Rather than instituting just one level of certification besides CCIE, Cisco created two additioanl

levels: an Associate level and a Professional level. CCNA is the more basic, and CCNP is the

intermediate level between CCNA and CCIE. Likewise, CCDA is more basic than CCDP. You

can view these details at Cisco’s Web site, www.cisco.com/warp/public/10/wwtraining/

certprog/lan/course.html.

Several of the certifications require other certifications as a prerequsite. For instance, CCNP

certification requires CCNA first. Also, CCDP requires both CCDA and CCNA certification.

CCIE, however, does not require any other certification prior to the written and lab tests, mainly

for historical reasons.

Cisco certifications have taken on a much larger role in the networking industry. From a career

standpoint, Cisco certification certainly can be used to help you get a new job. Or, you can add

certification to your performance evaluation plan and justify a raise based on passing an exam.

If you are looking for a new job, not only might certification help you land the job, but it actually

might help you make more money!

Chapter 1: All About the Cisco Certified Network Associate Certification

To certify for CCNA, a single exam is required: Sylvan Prometric exam number 640-507. For

CCDA, a single exam is required as well, but multiple exams are required for CCNP and CCDP.

The exams generally match the same topics that are covered in one of the official Cisco courses,

but in most cases—and certainly on the CCNA exam—more topics are covered on the exam

than are in the course. Table 1-1 outlines the exams and the courses with which they are most

closely matched.

CCNA 640-507 CCNA Exam Interconnecting Cisco Network Devices (ICND)

CCDA 640-441 CCDP Exam Designing Cisco Networks

CCNP 640-503 Routing Exam Building Scalable Cisco Networks (BSCN)

640-504 Switching

Exam

Building Cisco Multilayer Switched Networks

(BCMSN)

640-505 Remote

Access Exam

Building Cisco Remote Access Networks

(BCRAN)

640-509* Foundation

Exam

BSCN, BCMSN, and BCRAN

640-506 Support Exam Cisco Internetwork Troubleshooting (CIT)

Overview of Cisco Certifications

* Exam 640-509 meets the same requirements as passing these three exams: 640-503, 640-504, and 640-505.

Be cautioned that, while the exam coverage and course coverage are similar, there are no

guarantees that you will pass the test if you know absolutely everything in the course. Cisco is

moving more toward tying the certifications to technology, not to specific courses; note that the

exam names do not match the course names, as they previously did. So, a study guide can help

you with the other certifications as well as CCNA, with the added guidance of stressing the most

important exam items and covering other topics not held in the prerequisite courses.

The certifications mentioned so far are oriented toward routing and LAN switching. Cisco has

many other certifications as well, as summarized in Table 1-2. Refer to Cisco’s Web site at

www.cisco.com/warp/public/10/wwtraining/certprog/index.html for the latest information.

CCDP 640-503 Routing Exam Building Scalable Cisco Networks (BSCN)

640-504 Switching

Exam

Building Cisco Multilayer Switched Networks

(BCMSN)

640-505 Remote

Access Exam

Building Cisco Remote Access Networks

(BCRAN)

640-509* Foundation

Exam

BSCN, BCMSN, and BCRAN

640-025 CID Exam Cisco Internetwork Design (CID)

CCNA-WAN Basic certification for Cisco WAN switches.

CCNP-WAN Intermediate certification for Cisco WAN switches. Requires CCNAWAN.

CCDP-WAN Design certification for Cisco WAN switches. Requires CCNP-WAN.

CCIE-WAN Expert-level certification for Cisco WAN switches. No prerequisite.

Requires exam and lab.

CCIE-ISP Dial CCIE-level certification for Internet service provider (ISP) and dial

network skills. No prerequisite. Requires exam and lab.

Chapter 1: All About the Cisco Certified Network Associate Certification

Every test-taker would like to know exactly what is on the CCNA exam, as well as the other

Cisco certification exams. Well, to be honest,

what is on the exam is a very closely

guarded secret. Only those who write the questions for Cisco, and who have access to the entire

question database, truly know what is really on the exam.

Cisco makes fairly general CCNA exam content available to the public at the Web site

www.cisco.com/warp/public/10/wwtraining/certprog/lan/course.html. In fact, two direct

quotes from this Web site sumarize the exam:

CCNA Certification skills: Install, configure, and operate simple-routed LAN, routed

WAN, and switched LAN networks.

What defines “simple” networks: IP, IGRP, IPX, Serial, AppleTalk, Frame Relay, IP RIP,

VLANs, IPX RIP, Ethernet, Access Lists.

Frankly, most people could guess more detail about the exam than what these two quotes say

about it. As Cisco’s authorized external publishing company, Cisco Press provides some

additional information, part of which includes some details that are expected to be posted on

Cisco’s Web site at a later date. At press time, Cisco had not finalized what other details about

the exam will be posted on the Web site, so none of those details can be discussed here.

Fortunately, you’ll have easy access to what Cisco does decide to post. Be sure to check Cisco’s

Web site for the latest information on the exam.

A couple of comments can be made about the exam in general:

•

If we at Cisco Press believe that a topic is definitely on the exam, it is covered in Chapters

2 through 8.

•

If we at Cisco Press believe that a topic is simply not in the Cisco CCNA question

database, then it is not covered in this book. The only exception would be a topic that is

not on the exam that must be explained in order to make a topic that is on the exam more

understandable.

CCIE-SNA-IP Expert-level certification for Cisco products and features used for melding

SNA and IP networks. No prerequisite. Requires exam and lab.

CCNP and CCDP

specializations

Several specialized certifications are available for CCNP and CCDP

(routing/switching); see www.cisco.com/warp/public/10/wwtraining/

certprog/special/course.html for more details.

Topics on the Exam

The following list outlines the topics that will be the focus of the exam. These topics are shown

corresponding to the chapters in which they are covered.

•

Chapter 2, “Cisco Internetwork Operating System (IOS) Fundamentals”

Router components

The IOS CLI

Managing configuration files

Cisco Discovery Protocol (CDP)

Upgrading flash memory

IOS initialization

•

Chapter 3, “OSI Reference Model & Layered Communication”

OSI layers, benefits of layering, interactions of OSI layers

TCP/IP and NetWare comparisons with OSI

Connectionless and connection-oriented protocols

Data link layer functions

Network layer functions: addressing and routing

•

Chapter 4, “Bridges/Switches and LAN Design”

LAN addressing and framing

Fast Ethernet and Gigabit Ethernet

LAN standards

Transparent bridging

LAN switching

Spanning-Tree Protocol

LAN switch configuration (1900 family)

VLAN trunking protocol

Chapter 1: All About the Cisco Certified Network Associate Certification

•

Chapter 5, “Network Protocols”

TCP/IP

IP addressing and subnetting

TCP/IP configuration

IPX addressing and routing

IPX configuration

•

Chapter 6, “Routing”

Distance vector routing protocols

Configuration of IP RIP and IP IGRP

Autosummarization and route aggregation

IPX RIP, SAP, and GNS concepts

IPX configuration

Tunneling

Integrated routing protocols

•

Chapter 7, “Understanding Access List Security”

Filtering IP traffic

Filtering IPX traffic

•

Chapter 8, “WAN Protocols and Design”

Frame Relay concepts and configuration

Point-to-point concepts and configuration

ISDN concepts

Dial-on-Demand Routing (DDR)

Recommended Training Path for CCNA

Cisco recommends that you take two courses before you take the CCNA exam. The first,

Internetworking Technology Multimedia (ITM), is a CD-based course that you can order

directly from Cisco (www.cisco.com/warp/customer/10/wwtraining/cust/course_itm.html)

currently for $50. This course covers many of the protocol basics needed for CCNA.

The other suggested course is the instructor-led Interconnecting Cisco Network Devices

(ICND) course, which is available from almost every Cisco training partner (for a list of training

partners, go to www.cisco.com/warp/public/10/wwtraining/listAllTP.html). The ICND course

replaces the old Introduction to Cisco Router Configuration (ICRC) course, as well as the lesspopular

Cisco Routing and LAN Switching (CRLS) course.

So, if you have taken or will take ICND, that’s the best way to prepare for the CCNA exam.

Reading the ITM CD will be helpful as well. But what if you took one of the older courses? Or,

what if you took the Cisco Networking Academy curriculum? Or, what if you simply choose

not to spend the money on an introductory course? The final section of this chapter suggests a

strategy for people from each background.

First, an outline of the ICND course, shown in Table 1-3, should be helpful. Remember,

although the CCNA exam is not a test on the ICND course, ICND is the course that most closely

matches the CCNA topics.

Interconnecting Cisco

Networking Devices Introduction

Typical administrative details.

Internetworking Concepts

Overview

OSI model details; common physical and data link specifications;

MAC address definition; description of Ethernet, Token Ring, and

FDDI operation; a brief explanation of WAN data links.

Assembling and Cabling Cisco

Devices

Short chapter on basic physical setup and cabling.

Operating and Configuring a

Cisco IOS Device

Logging in, initialization, modes of operation, passwords, help,

command editing, and various

commands.

Managing Your Network

Environment

Telnet, CDP, and managing the IOS and config files.

Catalyst 1900 Switch Operations LAN switching concepts, spanning tree, and 1900 switch

configuration.

Extending Switched Networks

with Virtual LANs

Virtual LANs, VLAN trunking, and VLAN configuration on 1900

switches.

Chapter 1: All About the Cisco Certified Network Associate Certification

One way to use this book is to start at the beginning and read it cover to cover. Although that

certainly would help you prepare, most people would not take that much time, particularly if

you already knew a lot about some of the topics in the book.

The rest of you might want to consider a different strategy on how to best use this book,

depending on what training you have had. This book is designed to help you get the most out

of the time you take to study.

Interconnecting Networks with

TCP/IP

Protocol stack versus OSI; application layer examples; TCP error

recovery; TCP and UDP ports; TCP, UDP, and IP headers; and

ICMP. For Class A, B, and C networks: IP addresses, mask

subnetting, and planning; configuring IP addresses; configuring

host names; configuring DNS; and verifying operation with

,

, and

commands.

Determining IP Routes Configuring static routes; configuring default routes; interior

versus exterior routing protocols; configuring RIP; debugging

RIP; IGRP configuration; and IGRP

and

commands.

Basic IP Traffic Management with

Access Lists

The purpose of using access lists, logic diagrams, standard and

extended access lists, and TCP/IP access lists; wildcard masks;

configuring standard IP access lists; configuring extended access

lists; monitoring IP access lists.

Configuring Novell IPX Protocol versus OSI, IPX addresses, Novell encapsulation

options, RIP, SAP, GNS, configuring IPX, displaying IPX,

debugging IPX, and IPX access-lists.

Establishing Serial Point-to-point

Connections

Telephone company service basics, survey of data link protocols

for WANs, SDLC/HDLC/PPP/LAPB framing, PPP functions,

PAP and CHAP authentication, and PAP and CHAP

configuration.

Completing an ISDN BRI Call ISDN Protocol basics and dial-on-demand routing (DDR).

Establishing a Frame Relay PVC

Connection

Terminology, LMI messages, Inverse ARP, addressing,

configuration, monitoring, configuration using subinterfaces,

NBMA, and full and partial mesh issues.

The core material for the CCNA is covered in Chapters 2 through 8. At the beginning of each

chapter, you are instructed on how to make the best use of your time reading that chapter,

assuming that you are not going to read every detail. The instructions on how to use each

chapter are outlined in Figure 1-2.

If you get a high score, you might simply review the “Foundation Summary” section at the end

of the chapter. If you score well on one quizlet but low on another, you are directed to the

section of the chapter corresponding to the quizlet on which your score was low. If you score

less than 50 percent on the overall quiz, you should read the whole chapter. Of course, these are

simply guidelines—if you score well but want more review on that topic, read away!

After completing the core chapters (Chapters 2 through 8), you have several options for your

next study activity. Because Chapter 9, “Scenarios for Final Preparation,” is the next chapter in

succession, it outlines the directions on what to do next. These same directions are repeated here

as well. Figure 1-3 outlines your options for final study for the exam.

As shown, if you want even more final preparation, you can go over the many practice questions

located in each chapter and on the CD. All pre-chapter quiz and chapter-ending questions, with

answers, are in Appendix A, “Answers to the ‘Do I Know This Already?’ Quizzes and Q&A

Sections.” You can read and review these conveniently located questions and explanations

quickly. The CD includes testing software, as well as many additional questions in the format

of the CCNA exam. These questions should be a valuable resource when performing final

preparations.

Anyone preparing for the CCNA exam can use the guidelines at the beginning of each chapter

as a study aid. However, for some additional guidance, the final parts of this chapter give a few

strategies for study, based on how you have prepared before buying this book. So, find the

section that most closely matches your background in the next few pages, and read about some

additional ideas to help you prepare. There is a section for people who have taken ICND, one

for those who have taken ICRC, one for those from the Cisco Networking Academies, one for

those who will not be taking any classes and have not had much experience, and a final set of

strategies for those who will not be taking any classes but who have some experience.

For starters, you’ve taken the best path to prepare yourself. But let me temper that with the fact

that if you retain more than 50 percent of what you heard in class, then you are an extraordinary

person! That said, you need the following three strategies:

respectively. Each of the foundational chapters begins with a quiz that helps you assess what

you need to study. It then directs you to the appropriate sections in the chapter rather than

requiring you to read all of each chapter.

These section titles are as follows:

the exam. Chapter 9 is designed to review many concepts, and it outlines a good process for

study in the days leading up to your exam.

By using these three strategies, you will fill in the gaps in your knowledge and be confident

taking your CCNA exam.

The current version of the exam more closely matches the ICND class. However, if you

compared the two course books, you would find much more in common than is different. In

fact, more than half of ICND is directly taken from the ICRC course. Of course, if you retain

more than 50 percent of what you heard in class, then you are an extraordinary person, so you

probably still need to fill in some holes in your knowledge base. For you, the following

strategies will be most helpful:

ICRC did not cover LAN switching and Spanning-Tree Protocol, which are covered here in

detail. Do not skip the configuration sections, either—they are very important.

Each of the foundational chapters begins with a quiz that helps you assess what you need to

study. It then directs you to the appropriate sections in the chapter rather than requiring you to

read all of each chapter. In fact, you probably should use Chapter 4 this way as well, in spite of

having read it already, because that will validate what you have learned.

Other than almost all of Chapter 4 of this book, the section titles you will want to be sure to read

are as follows:

the exam. Chapter 9 is designed to review many concepts, and it outlines a good process for

study in the days leading up to your exam.

So, compared to those who have taken ICND, you should not require a lot of additional study

time. The ICRC course did a great job of explaining the basics, and hopefully this book will

help you retain enough to confidently pass the exam.

First of all, congratulations on having the foresight to get into the Cisco Networking Academy

program—we need more people who can make this stuff work! (Those of you who didn’t take

the Cisco Networking Academy track and are wondering what it’s all about, check out

www.cisco.com/warp/public/779/edu/academy/.) Thankfully, the Networking Academy

curriculum actually does a great job of preparing you with the skills and knowledge you need

to pass the exam. Unfortunately, your study was probably spread over several semesters, and

possibly over a couple of years. So, the details that you do not use frequently may have been

forgotten. Now, on to the strategies for success on CCNA:

people’s memory is exercised better by seeing familiar material—and even more so when you

wrote it down yourself. If you have ever taken a test and pictured in your mind where the answer

was on your page of notes, then you can relate.

Each of the foundational chapters begins with a quiz that helps you assess what you need to

study. It then directs you to the appropriate sections in the chapter rather than requiring you to

read all of each chapter.

and some of the standards. The biggest reason for that is that the Networking Academy is

oriented more toward building skills than theoretical knowledge. The suggested sections are

listed here:

of the section “The TCP/IP and NetWare Protocols”

the exam. Chapter 9 is designed to review many concepts, and it outlines a good process for

study in the days leading up to your exam.

This book should help you sift through the topics and choose the right areas for study, and it

also should help you to not waste your time. Congratulations on your Networking Academy

work—now add the CCNA certification to take away any doubt in the minds of prospective

employers that you know Cisco!

You can pass the CCNA exam without taking any courses. Of course, Cisco wants you to take

the recommended courses for all the exams—its motivation is not to make more money,

because Cisco does not actually deliver the training; the training partners do. Instead, Cisco

truly believes that the more people understand its products, ultimately the happier its customers

will be and the more products Cisco will sell. Cisco also believes that the official training is the

right way to teach people about Cisco products, so you’re encouraged to take the classes.

If you are not taking any course, however, there is no reason to worry. Truthfully, though, you

in the course book, and the text comes from the course book, expanded and reorganized to work

well in book format. So, if you can’t get to the course, for not a lot of money you can buy the

ICND book.

Of course, this book will be helpful, too. Try these suggestions:

ICND course is listed as the only leader-led prerequisite course for CCNA.

Chapters 2 through 8. Each of the foundational chapters begins with a quiz that helps you assess

what you need to study. It then directs you to the appropriate sections in the chapter rather than

requiring you to read all of each chapter.

These section titles are as follows:

the exam. Chapter 9 is designed to review many concepts, and it outlines a good process for

study in the days leading up to your exam.

If you feel that you know a fair amount about CCNA topics already but are worried about the

topics you simply just have not worked with, then this strategy is for you. This book is designed

to help you figure out what CCNA topics you need some help with and then help you learn

about them. Here’s the simple strategy for you:

Each of the foundational chapters begins with a quiz that helps you assess what you need to

study. It then directs you to the appropriate sections in the chapter rather than requiring you to

read all of each chapter.

the exam. Chapter 9 is designed to review many concepts, and it outlines a good process for

study in the days leading up to your exam.

You should be able to fill in the gaps in your knowledge this way and not risk being bored in

the ICND class when it covers the topics you already know.

The CCNA certification is arguably the most important Cisco certification. It certainly is the

most popular, is required for several other certifications, and is the first step in distinguishing

yourself as someone who has proven knowledge of Cisco.

certification. This is the CCNA certification book from the only Cisco-authorized publisher. We

at Cisco Press believe that this book certainly can help you achieve CCNA certification—but

the real work is up to you! I trust that your time will be well spent.

This chapter covers the following topics that you will need to master as a CCNA:

•

This section examines the types of memory used

by the IOS, in addition to the commands used to examine and change the contents.

This section also describes the basic functions and help for the command-line

interface (CLI), and discusses how syslog messages are treated.

•

The configuration file used

for a router contains all the configuration for that router. This section covers all

commands used to change the configuration and manipulate the configuration file.

•

This section covers in detail the processes for upgrading

the IOS in Flash memory, as well as the commands used to tell the router which IOS

image to use. Password recovery is included as well.

The CCNA exam requires that you understand the basics of the Cisco Internetwork

Operating System (IOS). In fact, the only operating system and user interface covered on

the CCNA exam is the IOS and its user interface. The omission of other user interfaces, in

particular the Catalyst 5000/5500 series user interface, is one of the most important facts to

note when determining what to study for the CCNA exam.

The IOS runs on some Cisco switch models and provides the familiar IOS command-line

interface (CLI). This chapter is geared toward the IOS CLI on a router. Chapter 4, “Bridges/

Switches and LAN Design,” covers some details of IOS CLI on LAN switches. The user

interface is the same, but some commands are different.

The exam also includes questions on both router and LAN switch usage of the IOS. No one

should be surprised that the CCNA exam covers IOS running on routers. Also covered on

the exam is the use of IOS running on Cisco 1900 series switches. User interfaces on other

switch platforms might seem to be like IOS and have similar features, but these details are

not covered on the exam. That should be particularly helpful for those of you with less

hands-on experience.

Cisco requires that CCNAs exhibit a solid recollection of the many details of the CLI. Of

course, the best way to learn about any user interface is to use it. If you can spend time using

a Cisco router, the knowledge and recall you gain will be of significant value. This chapter

is designed to remind you of details you might not notice when practicing and will provide

a reference for those of you who do not have access to routers for practice. Still, there is no

substitute for hands-on practice.

By taking the following steps, you can make better use of your study time:

•

Keep your notes and the answers for all your work with this book in one place,

for easy reference.

•

Take the “Do I Know This Already?” quiz, and write down your answers. Studies

show that retention is significantly increased through writing down facts and

concepts, even if you never look at the information again.

•

Use the diagram in Figure 2-1 to guide you to the next step.

The purpose of the “Do I Know This Already?” quiz is to help you decide what parts of this

chapter to use. If you already intend to read the entire chapter, you do not necessarily need to

answer these questions now.

This 12-question quiz helps you determine how to spend your limited study time. The quiz is

sectioned into three smaller four-question “quizlets,” which correspond to the three major topic

headings in the chapter. Figure 2-1 outlines suggestions on how to spend your time in this

chapter based on your quiz score. Use Table 2-1 to record your scores.

1 The IOS and Its User Interface 1 to 4

2 Configuration Processes and the Configuration

File

5 to 8

3 Managing IOS Images 9 to 12

All questions 1 to 12

“Do I Know This Already?” Quiz

What are the two different names for the router’s mode of operation that, when accessed,

enables you to issue commands that could be disruptive to router operations?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

What command would you use to receive command help if you knew that a

command option begins with a

, but you cannot recall the option?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

After typing

, which is the only command you issued since logging in to the

router, you now want to issue the

command. What steps would you take to

execute this command by using command recall keystrokes?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

What is the name of the user interface mode of operation used when you cannot issue

disruptive commands?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

What configuration command causes the router to require a password from a user at the

console? What configuration mode context must you be in—that is, what command(s)

must be typed before this command after entering configuration mode? List the

commands in the order in which they must be typed while in config mode.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

What does CDP stand for?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Chapter 2: Cisco Internetwork Operating System (IOS) Fundamentals

What does the NV stand for in NVRAM?

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

Name two commands used to view the configuration that is currently used in a router.

Which one is a more recent addition to the IOS?

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

What two methods could a router administrator use to cause a router to load the IOS stored

in ROM?

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

What is the process used to update the contents of Flash memory so that a new IOS in a

file called c4500-d-mz.120-5.bin, on TFTP server 128.1.1.1, is copied into Flash

memory?

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

Two different IOS files are in a router’s Flash memory: one called c2500-j-l.111-3.bin and

one called c2500-j-l.112-14.bin. Which one does the router use when it boots up? How

could you force the other IOS file to be used? Without looking at the router configuration,

what command could be used to discover which file was used for the latest boot of the

router?

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

What are the primary purposes of Flash memory in a Cisco router?

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

“Do I Know This Already?” Quiz

The answers to the “Do I Know This Already?” quiz are found in Appendix A, “Answers to the

‘Do I Know This Already?’ Quizzes and Q&A Sections,” on page 701. The suggested choices

for your next step are as follows:

•

—Read the entire chapter. This includes the “Foundation Topics”

and “Foundation Summary” sections, the Q&A section, and the scenarios at the end of the

chapter.

•

—Review the subsection(s) of the “Foundation Topics” part of

this chapter, based on Table 2-1. Then move into the “Foundation Summary” section, the

Q&A section, and the scenarios at the end of the chapter.

•

—Begin with the “Foundation Summary” section and then go to

the Q&A section and the scenarios at the end of the chapter.

•

—If you want more review on these topics, skip to the

“Foundation Summary” section and then go to the Q&A section and the scenarios at the

end of the chapter. Otherwise, move to the next chapter.

Chapter 2: Cisco Internetwork Operating System (IOS) Fundamentals

IOS, a registered trademark of Cisco Systems, is the name of the operating system found in

most of Cisco’s routers. The majority of Cisco routers run the IOS, with its familiar commandline

interface (CLI). Also, some routing cards in other devices run IOS. For example, the Route/

Switch Module (RSM) card for the Catalyst 5000 series LAN switches performs routing

functions and executes the IOS.

Fixes and code updates to the IOS can include new features and functions. To learn more about

the code release process, features added at particular IOS revision levels, and other terminology

that will help you talk to the Cisco Technical Assistance Center (TAC), check out a current

Cisco Product Bulletin describing the Software Release Process. One such example is Product

Bulletin #537 (http://www.cisco.com/warp/public/cc/cisco/mkt/ios/rel/prodlit/537_pp.htm).

The exam topics covered in this section will become second nature to you as you work with

Cisco routers and switches more often. In fact, because this book purposefully was written for

an audience that already has some training and experience with Cisco routers, several of the

details in this chapter might already be ingrained in your memory. If you would like more

review, or if you are still new to the IOS, read on—the details in this section are important to

using Cisco routers and switches. This chapter reviews such topics as router components, the

CLI, and how to navigate the IOS command set using Help and key sequences for command

edit and recall.

Before examining the IOS, a review of hardware and hardware terminology is useful. In

addition to handling the logic of routing packets, the IOS controls the use of different physical

components, which includes memory, processor, and interfaces. This section of the book

reviews common hardware details.

All Cisco routers have a console port, and most have an auxiliary port. The console port is

intended for local administrative access from an ASCII terminal or a computer using a terminal

emulator. The auxiliary port, missing on a few models of Cisco routers, is intended for

asynchronous dial access from an ASCII terminal or terminal emulator; the auxiliary port is

often used for dial backup.

Each router has different types of memory, as follows:

•

—Sometimes called DRAM for

random-access memory, RAM is used by

the router just as it is used by any other computer: for working storage.

The IOS and Its User Interface

•

—This type of memory (read-only memory) stores a bootable IOS image, which is

not typically used for normal operation. ROM contains the code that is used to boot the

router until the router knows where to get the full IOS image.

•

—Either an EEPROM or a PCMCIA card, Flash memory stores fully

functional IOS images and is the default where the router gets its IOS at boot time. Flash

memory also can be used to store configuration files on Cisco 7500 series platforms.

•

—Nonvolatile RAM stores the initial or

configuration file.

All these types of memory are permanent memory except RAM. No hard disk or diskette

storage exists on Cisco routers. Figure 2-2 summarizes the use of memory in Cisco routers.

The processors in the routers vary from model to model. Although they are not specifically

listed as requirements for the CCNA exam, some reference to terminology is useful. In most

routers, only one processor option is available; thus, you would not order a specific processor

type or card. The exception to this is the 7200 and 7500 families of routers. For instance, on the

7500 series, you choose either a Route Switch Processor 1 (RSP-1), RSP-2, or RSP-4

processor. In any case, all 7200 and 7500 routers, as well as most of the other Cisco router

families, run IOS. This commonality enables Cisco to formulate exams, such as CCNA, that

cover the IOS features without having to cover many hardware details.

Interfaces are used by a router for routing packets and bridging frames through a router. The

types of interfaces available change over time due to new technology. For example, packetover-

SONET and voice interfaces are relatively recent additions to the product line. However,

some confusion exists about what to call the actual cards that house the physical interfaces.

Table 2-2 summarizes the terminology that might be referred to on the test.

2500 Interface Modules and WAN interface cards

3600 Interface Network modules and WAN interface cards

4500 Interface Network processor modules

7200 Interface Port adapters and service adapters

7500 Interface Interface processors, and versatile interface

processors with port adapters

Chapter 2: Cisco Internetwork Operating System (IOS) Fundamentals

Physical interfaces are referred to as

by the IOS commands, as opposed to

or

. IOS commands familiar on one platform will be familiar on another. Some nuances are

involved in numbering the interfaces, however. In some smaller routers, the interface number is

a single number. However, with some other families of routers, the interface is numbered first

with the slot in which the card resides, followed by a slash and then the port number on that

card. For example, port 3 on the card in slot 2 would be interface 2/3. Numbering starts with 0

for card slots and 0 for ports on any card. In some cases, the interface is defined by three

numbers: first the card slot, then the daughter card (typically called a port adapter), and then a

number for the physical interface on the port adapter. The 2600 and 3600 families also use a

slot/port numbering scheme.

In this book, the single-digit interface numbers are used simply for consistency and readability.

If you want to dig deeper, you might want to read about processors and interfaces in the Cisco

Product Catalog (http://www.cisco.com/univercd/cc/td/doc/pcat/).

Cisco uses the acronym CLI to refer to the terminal user command-line interface to the IOS.

The term CLI implies that the user is typing commands at a terminal, terminal emulator, or

Telnet connection. Although you can pass the CCNA exam without ever having used the CLI,

actually using the CLI will greatly enhance your chances.

To access the CLI, use one of three methods, as illustrated in Figure 2-3.

The IOS and Its User Interface

Regardless of which access method is used, a CLI user initially is placed in user mode, or user

EXEC mode, after logging in.

refers to the fact that the commands typed here are

executed, and some response messages are displayed onscreen. The alternative mode is

, which is covered in the next section.

Passwords can be required when accessing the CLI. In fact, the default configuration at IOS

12.x requires a password for Telnet and auxiliary port access, but no password is set—therefore,

you must configure passwords from the console first. Table 2-3 reviews the different types of

passwords and the configuration for each type.

The

command actually tells the router to display a prompt. The

commands

specify the text password to be typed by the user to gain access. The first command in each

configuration is a context-setting command, as described in the section “Configuration

Processes and the Configuration File,” later in this chapter. Typically, all three passwords have

the same value.

Several concurrent Telnet connections to a router are allowed. The

command

signifies that this configuration applies to vtys (virtual teletypes—terminals) 0 through 4. Only

these five vtys are allowed by the IOS unless it is an IOS for a dial access server, such as a Cisco

AS5300. All five vtys typically have the same password, which is handy because users

connecting to the router via a Telnet cannot choose which vty they get.

User EXEC mode is one of two command EXEC modes in the IOS user interface.

mode

(also known as

mode or

mode) is the other. Enable mode is so

named because of the command used to reach this mode, as shown in Figure 2-4; privileged

mode earns its name because powerful, or privileged, commands can be executed there.

Console Console password

Auxiliary Auxiliary password

Telnet vty password

Several references are available for help when you are using the IOS. IOS documentation is

available on CD and is free from Cisco if you own one router or switch under a current

maintenance agreement. Paper documentation is also available from Cisco. If you prefer, Cisco

Press offers the Cisco Documentation series (more information at www.ciscopress.com). In

addition, all Cisco documentation is available online at Cisco’s Web site (www.cisco.com/

univercd/home/home.htm); the IOS command reference is found at www.cisco.com/univercd/

cc/td/doc/product/software/ios120/12cgcr/index.htm.

No matter which documentation you use, it is incredibly unlikely that you will remember all

IOS commands. (The command reference manuals stack 14 inches high.) Therefore, you will

find tools and tricks to recall commands particularly useful. Table 2-4 summarizes command

recall help options available at the CLI. Note that in the first column, “Command” represents

any command. Likewise, “parm” represents a command’s parameter. For instance, the third row

spaces exist between “parm” and the ?.)

other keys. The router also redisplays what you typed before the ? to save you some keystrokes. If you press Enter

immediately after the ?, the IOS tries to execute the command with only the parameters you have typed so far.

** “Command” represents any command, not the word “command.” Likewise, “parm” represents a command’s

parameter, not the word “parameter.”

mode, the commands allowed only in privileged EXEC mode are not displayed. Also, help is

available in configuration mode; only configuration commands are displayed in that mode of

operation.

Commands you use at the CLI are stored in a command history buffer that retains the last

between 0 and 256.

Of course, most people want to use a previously typed command (perhaps with a different

parameter). Commands you have previously used during the current console/aux/Telnet can be

retrieved and then edited to save you some time and effort. This is particularly useful when you

are typing long configuration commands. Table 2-5 lists the commands used to manipulate

previously typed commands.

of this parameter at the command line for the user, or do nothing. If the

CLI does nothing, it means that this string of characters represents more

than one possible next parameter, so the CLI does not know which to

spell out.

parameters and gives a brief explanation of each.

Up-arrow or Ctrl+p This displays the most recently used command. If pressed again, the

next most recent command appears, until the history buffer is

Down-arrow or Ctrl+n If you have gone too far back into the history buffer, these keys will go

forward, in order, to the more recently typed commands. (The n is for

Left-arrow or Ctrl+b This moves the cursor backward in the currently displayed command

on the CCNA exam. Hopefully, Table 2-5 will further your understanding. Beware—these

details are covered on the exam questions.

Syslog and Debug

The IOS creates messages when different events occur and, by default, sends them to the

for any length of time, you likely have noticed these messages—and when they are frequent,

you probably became a little frustrated.

what the IOS is doing and seeing. When any debug command option is enabled, the router

options create so many messages that the IOS cannot process them all, possibly crashing the

IOS.

Right-arrow or Ctrl+f This moves the cursor forward in the currently displayed command

Backspace This moves the cursor backward in the currently displayed command,

deleting characters.

Ctrl+a This moves the cursor directly to the first character of the currently

displayed command.

Ctrl+e This moves the cursor directly to the end of the currently displayed

command.

Esc+b This moves the cursor back one word in the currently displayed

command.

Esc+f This moves the cursor forward one word in the currently displayed

command.

Ctl+r This creates a new command prompt, followed by all the characters

typed since the last command prompt was written. This is particularly

useful if system messages confuse the screen and it is unclear what the

user has typed so far.

to try to prevent the router from crashing by immediately disabling all debugs.

Users might or might not be interested in seeing the messages as they occur. The console port

always receives syslog messages. When a user telnets to the router, however, no syslog

simply means that this terminal is monitoring syslog messages. Another alternative for viewing

syslog messages is to have the IOS record the syslog messages in a buffer in RAM, and then

Telnet users do not get syslog messages by default anyway, these users can wait and look

subcommand can be used for the console and vtys to tell the router to wait until the user’s last

command output is displayed before showing any syslog messages onscreen. That provides a

little less interruption for the user.

Syslog messages also can be sent to another device. Two alternatives exist: sending the

messages to a syslogD server, and sending the messages as SNMP traps to a management

server, is used to enable sending messages to the external server. After SNMP is configured, the

Figure 2-5 summarizes the flow of syslog messages, including debug messages. For a more

detailed view of syslog messages, including restricting messages based on message severity,

refer to the IOS documentation CD manual called “Troubleshooting Commands.”

Cisco requires that CCNAs master the process of changing and manipulating the configuration

files in the IOS. This includes initially setting up an IOS device, handling ongoing

configuration, and moving configuration files.

As mentioned in Chapter 1, “All About the Cisco Certified Network Associate Certification”

configuration mode is another mode for the Cisco CLI. Changing the configuration of the router

by typing various configuration commands is the purpose of configuration mode. Figure 2-6

illustrates the relationships among configuration mode, user EXEC mode, and priviledged

EXEC mode.

Commands typed in configuration mode update the active configuration file. Changes are

moved into the active configuration file each time the user presses the Enter key and are acted

upon immediately by the router.

In configuration mode, context-setting commands are used before most configuration

commands. These context-setting commands tell the router the topic about which you will type

commands. More importantly, they tell the router what commands to list when you ask for help.

After all, the whole reason for these contexts is to make online help more convenient and clear

for you.

configuration mode.

displays only commands that are useful when configuring Ethernet interfaces. Commands used

The labels on the lines in Figure 2-7 represent the action or command that moves the user from

configuration mode.

If you have significant experience using the CLI in configuration mode, much of this will be

second nature. From a CCNA exam perspective, recalling whether popular commands are

global commands or subcommands will be useful. No set rules exist for what commands are

global or subcommands, but generally, when multiple instances of a parameter can be set in

a single router, the command used to set the parameter is likely to be a configuration subcommand.

Items that are set once for the entire router are likely to be global commands. For

subcommand that sets the IP address on the interface; each interface will have a different IP

address.

configuration mode) to exit configuration mode and return to privileged EXEC mode. The

back up one level toward global configuration mode.

Example 2-1 illustrates how the console password is defined; provides banner, host name,

prompt, and interface descriptions; and shows the finished configuration. The lines beginning

with “!” are comment lines that highlight significant processes or command lines within the

“!” to make the output more readable—many comment lines in the examples in this book were

added to explain the meaning of the configuration.

This Here’s the Rootin-est Tootin-est Router in these here Parts!

User Access Verification

Password:

Password:

Emma#

Building configuration...

Current configuration:

!

version 11.2

! Version of IOS on router, automatic command

no service udp-small-servers

no service tcp-small-servers

!

hostname Critter

prompt Emma

! Prompt overrides the use of the hostname as the prompt

!

enable password lu

! This sets the priviledge exec mode password

!

no ip domain-lookup

! Ignores all names resolutions unless locally defined on the router.

!

ipx routing 0000.3089.b170

! Enables IPX rip routing

!

interface Serial0

ip address 137.11.12.2 255.255.255.0

ipx network 12

!

interface Serial1

description this is the link to Albuquerque

ip address 137.11.23.2 255.255.255.0

ipx network 23

!

interface TokenRing0

ip address 137.11.2.2 255.255.255.0

ipx network CAFE

ring-speed 16

!

router rip

network 137.11.0.0

!

no ip classless

!

!

!

banner motd ^C This Here’s the Rootin-est Tootin-est Router in these here Parts! ^C

! Any text between the Ctl+C keystrokes is considered part of the banner, including

!the Enter key.!

line con 0

password cisco

login

! login tells the router to supply a prompt; password defines what the user must

!type!

!

line aux 0

line vty 0 4

password cisco

Login

!

End

The CCNA exam requires that you be able to distinguish between the configuration file used at

startup and the active configuration file. The startup configuration file is in NVRAM; the other

file, which is in RAM, is the one the router uses during operation. The router copies the stored

configuration file from NVRAM into RAM as part of the boot process. Exterior to the router,

configuration files can be stored as ASCII text files anywhere using TFTP.

Cisco provides several methods of manipulating configuration files. CiscoWorks and other

management products let you create configurations for one or many routers without logging on

to those routers. NetSys Connectivity Tools actually check all the configuration files in your

network, make suggestions for improvements, and uncover errors. The most basic method for

manipulating configuration files and moving them into and out of a router, however, is by using

and a TFTP server. The files can be copied between any pair, as Figure 2-8 illustrates.

The commands can be summarized as follows:

The first parameter is the “from” location; the next one is the “to” location. (Of course, choosing

the same option for both parameters is not allowed.)

comprised of a list of configuration commands referencing the same list number or name). The

allowed in the same access list. Effectively, any copy into RAM works just as if you typed the

commands in the order listed in the config file.

So, why did Cisco not include a replace action, similar to the action used to copy to NVRAM

or TFTP? Who knows? A replace action probably would require you to empty all routing tables,

which might cause an outage. Possibly, this particular nuance is a result of some Cisco

programmer who decided years ago to take the loaded gun out of users’ hands. However,

advanced users can accomplish the effect of a replace action by entering configuration mode

and issuing commands until the running config is changed as desired. This requires that the user

know whether each command will replace another that is like it in the RAM configuration file,

command.

simply erase the contents of the NVRAM configuration file. Of course, if the router is reloaded

at this point, there will be no initial configuration.

Viewing the Configuration and Old-Style Configuration Commands

Once upon a time, commands that were used to move configuration files among RAM,

ones confused.

Figure 2-9 shows both the old and new commands used to view configurations.

Initial Configuration (Setup Mode)

To pass the CCNA exam, you will need to be familiar with the differences between

configuration mode and setup mode. Setup mode is a router configuration mode that prompts

the user for basic configuration parameters. A Cisco router can be configured using the CLI in

configuration mode without using setup mode. Some users like to use setup mode, however,

particularly until they become more familiar with the CLI.

configuration mode discussed earlier. Setup mode allows only basic configuration.

Setup mode is a topic covered on the CCNA exam, so regardless of whether you plan to use it,

you must remember how it works. Figure 2-10 and Example 2-2 describe the process. Setup

mode is most frequently used when the router comes up with no configuration in NVRAM;

Example 2-2 shows a screen capture of using setup mode after booting a router with no

configuration in NVRAM.

Notice: NVRAM invalid, possibly due to write erase.

--- System Configuration Dialog ---

At any point you may enter a question mark ’?’ for help.

Use Ctrl+C to abort configuration dialog at any prompt.

Default settings are in square brackets ’[]’.Would you

like to enter the initial configuration dialog? [yes]:

First, would you like to see the current interface summary? [yes]:

Any interface listed with OK? value “NO” does not have a valid configuration

Interface IP-Address OK? Method Status Protocol

Serial0 unassigned NO unset down down

Serial1 unassigned NO unset down down

Ethernet0 unassigned NO unset reset down

Configuring global parameters:

The enable secret is a one-way cryptographic secret used

instead of the enable password when it exists.

The enable password is used when there is no enable secret

and when using older software and some boot images.

Configure IP? [yes]:

Configuring interface parameters:

Configuring interface Serial0:

Is this interface in use? [yes]:

Configure IP on this interface? [yes]:

Class B network is 163.4.0.0, 0 subnet bits; mask is /16

Configuring interface Serial1:

Configuring interface Ethernet0:

Configure IP on this interface? [yes]:

Class B network is 163.5.0.0, 0 subnet bits; mask is /16

The following configuration command script was created:

hostname fred

enable secret 5 $1$aMyk$eUxp9JmrPgK.vQ.nA5Tge.

enable password cisco2

line vty 0 4

password cisco

no snmp-server

!

As Example 2-2 illustrates, you can use two methods to get into setup mode. First, if you are at

the console and you power up the router, and if there is no configuration file in NVRAM, the

When you are finished with setup, you are asked whether you want to use this configuration. If

operation in the IOS that changes both files to include the same contents based on a single

action.

As of IOS version 12.0, the setup mode prompts no longer ask for the number of subnet bits.

Instead, the subnet mask used is requested, which is probably a lot better for most people. Other

fine details of the setup mode prompts have changed as well. Example 2-3 shows an example

using IOS version 12.0 and is simply shown here for reference.

ip routing

!

interface Serial0

ip address 163.4.8.3 255.255.0.0

!

interface Serial1

shutdown

no ip address

!

interface Ethernet0

ip address 163.5.8.3 255.255.0.0

!

end

Building configuration...[OK]

Use the enabled mode ’configure’ command to modify this configuration.

Press ENTER to get started!

--- System Configuration Dialog ---

At any point you may enter a question mark ’?’ for help.

Use Ctrl+c to abort configuration dialog at any prompt.

Default settings are in square brackets ’[]’.

Basic management setup configures only enough connectivity

for management of the system, extended setup will ask you

to configure each interface on the system

First, would you like to see the current interface summary? [yes]:

Any interface listed with OK? value “NO” does not have a valid configuration

Interface IP-Address OK? Method Status Protocol

Serial0 unassigned NO unset down down

Serial1 unassigned NO unset down down

TokenRing0 unassigned NO unset reset down

Configuring global parameters:

The enable secret is a password used to protect access to

privileged EXEC and configuration modes. This password, after

entered, becomes encrypted in the configuration.

The enable password is used when you do not specify an

enable secret password, with some older software versions, and

some boot images.

The virtual terminal password is used to protect

access to the router over a network interface.

Configure DECnet? [no]:

Configure AppleTalk? [no]:

Configure IPX? [no]:

Configure IP? [yes]:

Configure RIP routing? [no]:

Configure bridging? [no]:

Configuring interface parameters:

Configure IP on this interface? [yes]:

IP address for this interface: 163.4.8.3

Subnet mask for this interface [255.255.0.0] : 255.255.255.0

Class B network is 163.4.0.0, 24 subnet bits; mask is /24

Configure IP on this interface? [yes]:

IP address for this interface: 163.5.8.3

Subnet mask for this interface [255.255.0.0] : 255.255.255.0

Class B network is 163.5.0.0, 24 subnet bits; mask is /24

The following configuration command script was created:

hostname fred

enable secret 5 $1$Qxix$Fi3buBVGTpEig9AIPgzxC.

enable password cisco2

In the example, notice that an early prompt gives you the choice of performing a simpler

configuration for basic management. For instance, you may have the configuration editing in a

file on your PC, and all you need is enough IP working so that you can Telnet into the router to

copy the configuration. Also note that you have an option to start over after answering the

questions, which is very convenient for those of us who are poor typists.

Cisco Discovery Protocol (CDP) is used by Cisco routers and switches to ascertain basic

information about neighboring routers and switches. You can use this information to learn

addresses quickly for easier Simple Network Management Protocol (SNMP) management, as

well as learn the addresses of other devices when you do not have passwords to log in to the

other device.

line vty 0 4

password cisco

no snmp-server

!

no decnet routing

no appletalk routing

no ipx routing

ip routing

no bridge 1

!

interface Serial0

ip address 163.4.8.3 255.255.255.0

no mop enabled

!

interface Serial1

shutdown

no ip address

!

interface Ethernet0

ip address 163.5.8.3 255.255.255.0

!

end

[0] Go to the IOS command prompt without saving this config.

[1] Return back to the setup without saving this config.

[2] Save this configuration to nvram and exit.

Enter your selection [2]: 2

Building configuration...

[OK]Use the enabled mode ’configure’ command to modify this configuration._

Press ENTER to get started!

CDP is a Cisco proprietary protocol; to support forwarding CDP messages over an interface,

that interface must support SNAP headers. Any LAN interface, HDLC, Frame Relay, and ATM

all support CDP. The router or switch can discover Layer 3 addressing details of neighboring

routers—without even configuring that Layer 3 protocol—because CDP is not dependent on

any particular Layer 3 protocol.

CDP discovers several useful details from the neighboring device:

command switches back to the default state of CDP being enabled.

commands, with some commentary following.

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID

fred Ser 1 172 R 2500 Ser 1

Yosemite Ser 0.2 161 R 2500 Ser 0.2

-------------------------

Device ID: fred

Entry address(es):

IP address: 163.5.8.3

Platform: cisco 2500, Capabilities: Router

Interface: Serial1, Port ID (outgoing port): Serial1

Holdtime : 168 sec

Version :

Cisco Internetwork Operating System Software

IOS (tm) 2500 Software (C2500-D-L), Version 12.0(6), RELEASE SOFTWARE (fc1)

Copyright 1986-1999 by cisco Systems, Inc.

Compiled Tue 10-Aug-99 23:52 by phanguye

-------------------------

Device ID: fred

Entry address(es):

The commands provide information about both the neighbors and the behavior of the CDP

CDP are shown and highlighted. To know that fred is the device identifier of a neighbor, the

functions.

IP address: 163.5.8.3

Platform: cisco 2500, Capabilities: Router

Interface: Serial1, Port ID (outgoing port): Serial1

Holdtime : 164 sec

Version :

Cisco Internetwork Operating System Software

IOS (tm) 2500 Software (C2500-D-L), Version 12.0(6), RELEASE SOFTWARE (fc1)

Copyright 1986-1999 by cisco Systems, Inc.

Compiled Tue 10-Aug-99 23:52 by phanguye

-------------------------

Device ID: Yosemite

Entry address(es):

IP address: 10.1.5.252

Novell address: 5.0200.bbbb.bbbb

Platform: cisco 2500, Capabilities: Router

Interface: Serial0.2, Port ID (outgoing port): Serial0.2

Holdtime : 146 sec

Version :

Cisco Internetwork Operating System Software

IOS (tm) 2500 Software (C2500-D-L), Version 12.0(6), RELEASE SOFTWARE (fc1)

Copyright 1986-1999 by cisco Systems, Inc.

Compiled Tue 10-Aug-99 23:52 by phanguye

Seville#show cdp interface

Ethernet0 is up, line protocol is down

Encapsulation ARPA

Sending CDP packets every 60 seconds

Holdtime is 180 seconds

Serial0.2 is up, line protocol is up

Encapsulation FRAME-RELAY

Sending CDP packets every 60 seconds

Holdtime is 180 seconds

Serial1 is up, line protocol is up

Encapsulation HDLC

Sending CDP packets every 60 seconds

Holdtime is 180 seconds

CDP counters :

Packets output: 41, Input: 21

Hdr syntax: 0, Chksum error: 0, Encaps failed: 0

No memory: 0, Invalid packet: 0, Fragmented: 0

a term referring to the file containing the IOS. Managing image files entails getting new IOS

images from Cisco; backing up the currently used, older version from your routers; updating

your routers with the new image; and testing. Also included in IOS image management is how

to tell a router to use a particular IOS the next time it boots.

IOS files are typically stored in Flash memory. Flash memory is rewritable, permanent storage,

which is ideal for storing files that need to be retained when the router loses power. Also,

because there are no moving parts, there is a smaller chance of failure as compared with disk

drives, which provides better availability.

As Figure 2-11 illustrates, to upgrade an IOS image into Flash memory, you first must obtain

the IOS image from Cisco. Then, you must place the IOS image into the default directory of a

Flash memory.

Example 2-5 provides an example of the final step, copying the IOS image into Flash memory.

R1#copy tftp flash

System flash directory:

File Length Name/status

1 7530760 c4500-d-mz.120-2.bin

[7530824 bytes used, 857784 available, 8388608 total]

Source file name? c4500-d-mz.120-5.bin

Destination file name [c4500-d-mz.120-5.bin]?

Accessing file c4500-d-mz.120-5.bin ’ on 134.141.3.33...

Loading c4500-d-mz.120-5.bin from 134.141.3.33 (via TokenRing0): ! [OK]

Erase flash device before writing? [confirm]

Flash contains files. Are you sure you want to erase? [confirm]

Copy ‘c4500-d-mz.120-5.bin ’ from server

as ‘c4500-d-mz.120-5.bin ’ into Flash WITH erase? [yes/no]y

Erasing device... eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ...erased

Loading c4500-d-mz.120-5.bin from 134.141.3.33 (via TokenRing0):

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!

[OK – 7530760/8388608 bytes]

Verifying checksum... OK (0xA93E)

Flash copy took 0:04:26 [hh:mm:ss]

R1#

During this process of copying the IOS image into Flash memory, the router will need to

discover several important facts:

The router will prompt you for answers, as necessary. Afterward, the router erases Flash

memory as needed, copies the file, and then verifies that the checksum for the file shows that

families.) Before the new IOS is used, however, the router must be reloaded.

In some cases, Flash memory could be in read-only mode. That is the case when a router loads

only part of the IOS into RAM, to conserve RAM. Other parts of the IOS file are kept in Flash

memory (Flash memory access time is much slower than RAM). In this case, if Flash memory

must be erased to make room for a new image, the IOS could not continue to run. So, if the

router is running from a portion of the IOS in Flash memory, the router first must be booted

using the IOS in ROM. Then the Flash memory will be in read/write mode, and the erase and

actually performs the entire process for you. In earlier releases, you had to boot the router from

The CCNA exam requires you to be proficient in configuring a router to load an IOS image from

many sources. Two methods are used by a router to determine where it tries to obtain an IOS

software register in Cisco’s more recently developed routers. (Some older routers had a hardware

configuration register, with jumpers on the processor card, to set bits to a value of 0 or 1.)

The second method used to determine where the router tries to obtain an IOS image is through

breakdown of the default value for the configuration register.

System flash directory:

File Length Name/status

1 6181132 c4500-d-mz.120-5.bin

[4181196 bytes used, 4207412 available, 8388608 total]

8192K bytes of processor board System flash (Read ONLY)

be considered a 4-bit value, represented as a single hexadecimal digit. Cisco represents

not found, then the router will never complete the boot process. The password recovery process

must be used to change the config register to 0x2161 so that the NVRAM configuration is

section “Password Recovery,” later in this chapter, for more details.)

0x0 Ignored if present ROM monitor mode, a low-level problem

determination mode, is entered.

0x1 Ignored if present IOS from ROM is loaded.

fails, the router broadcasts looking for an IOS

on a TFTP server. If that fails, IOS from ROM

is loaded.

memory.

server.

0x2-0xF Multiple boot system commands,

any variety

An attempt occurs to load IOS based on the

first boot command in configuration. If that

fails, the second boot command is used, and

so on, until one is successful.

15 14 13 12

0 0 1 0

11 10 9 8

0 0 0 1

7 6 5 4

0 0 0 0

3 2 1 0

0 0 1 0

Password Recovery

Several additional concepts related to loading the IOS must be understood before password

on all routers and actually provides the code that is first used to boot each router. rommon has

a rudimentary command structure that is used as part of the password recovery process. A

in either case, the IOS in bootflash or ROM is used mainly in cases where the IOS in flash is

not available for some reason. Finally, bit 6 of the configuration register set to binary 1 means

that the router should ignore the NVRAM configuration when booting.

Password recovery revolves around the process of getting the router to boot while ignoring the

NVRAM configuration file. The router will be up, but with a default configuration; this enables

a console user to log in, enter privileged mode, and change any encrypted passwords or view

any unencrypted passwords. To cause the router to ignore NVRAM at boot time, the

configuration register must be changed. To do that, you must be in privileged mode—and if you

were already there, you could reset any encrypted passwords or view any unencrypted ones.

It seems to be a viscious circle.

The two keys to password recovery are knowing that rommon enables you to reset the

configuration register and that a console user can get into rommon mode by pressing the Break

key during the first 60 seconds after power-on of the router. Knowing how to reset the config

register enables you to boot the router (ignoring NVRAM), allowing the console user to see or

change the unencrypted or encrypted passwords, respectively.

The process is slightly different for different models of routers, although the concepts are

identical. Table 2-7 outlines the process for each type of router.

1 Turn router off and then back

on again.

Use the power switch. Same as other routers.

2 Press the Break key within

the first 60 seconds.

Find the Break key on your

console devices keyboard.

Same as other routers.

3 Change the configuration

register so that bit 6 is 1.

Use the rommon command

prompts.

Use the rommon command

4 Cause the router to load

an IOS.

command or, if unavailable,

power off and on.

Use rommon command

5 Avoid using setup mode,

which will be prompted for

at console.

Just say no. Same as other routers.

with questions that correspond to the functions of the bits in the configuration register. When

“Change boot characteristics[y/n]?”, which asks whether you want to change the boot field of

the config register. You don’t really need to change it, but the published password recovery

algorithm lists that step, which is the only reason that it is mentioned here. Just changing bit 6

to 1 is enough to get the router booted and you into privileged mode to find or change the

passwords.

The original configuration is lost through this process, but you can overcome that. When you

save the configuration in Step 10, you are overwriting the config in NVRAM. There was no

configuration in the running config except default and the few things you configured. So, before

proceed with the process.

6 Enter privileged mode at

console.

command (no password

required).

Same as other routers.

7 View startup config to see

unencrypted passwords.

Same as other routers.

8 Use appropriate config

commands to reset

encrypted commands.

set enable secret password.

Same as other routers.

9 Change config register back

to original value.

Use config command

Same as other routers.

10 Reload the router after

saving the configuration.

Same as other routers.

The Foundation Summary is a collection of tables and figures that provide a convenient review

of many key concepts in this chapter. For those of you already comfortable with the topics in

this chapter, this summary could help you recall a few details. For those of you who just read

this chapter, this review should help solidify some key facts. For any of you doing your final

preparation before the exam, these tables and figures will be a convenient way to review the day

before the exam.

Table 2-8 reviews the different types of passwords and the configuration for each type.

Table 2-9 lists the commands used to manipulate previously typed commands.

Up-arrow or Ctrl+p This calls up the most recently used command. If pressed again,

the next most recent command appears, until the history buffer is

Down-arrow or Ctrl+n If you have gone too far back into the history buffer, these keys will

go forward, in order, to the more recently typed commands.

Left-arrow or Ctrl+b This moves the cursor backward in the currently displayed

Right-arrow or Ctrl+f This moves the cursor forward in the currently displayed command

initialization.

Backspace This moves the cursor backward in the currently displayed

command, deleting characters.

Ctrl+a This moves the cursor directly to the first character of the currently

displayed command.

Ctrl+e This moves the cursor directly to the end of the currently displayed

command.

Esc+b This moves the cursor back one word in the currently displayed

command.

Esc+f This moves the cursor forward one word in the currently displayed

command.

Ctrl+r This creates a new command prompt, followed by all the

characters typed since the previous command prompt. This is

particularly useful if system messages confuse the screen and it

is unclear what the user has typed so far.

0x0 Ignored if present ROM monitor mode, a low-level problem

determination mode, is entered.

0x1 Ignored if present IOS from ROM is loaded.

fails, IOS from ROM is loaded. If that fails,

the router broadcasts looking for an IOS on a

TFTP server.

memory.

TFTP server.

0x2-0xF Multiple boot system commands,

any variety

An attempt occurs to load IOS based on the

first boot command in configuration. If that

fails, the second boot command is used, and

so on, until one is successful.

Figure 2-13 summarizes the use of memory in Cisco routers.

Figure 2-14 illustrates the relationships among configuration mode, user EXEC mode, and

priviledged EXEC mode.

server. The files can be copied between any pair, as Figure 2-15 illustrates.

As mentioned in Chapter 1, the questions and scenarios in this book are more difficult than what

you should experience on the actual exam. The questions do not attempt to cover more breadth

or depth than the exam; however, they are designed to make sure that you know the answer.

Rather than allowing you to derive the answer from clues hidden inside the question itself, the

questions challenge your understanding and recall of the subject. Questions from the “Do I

Know This Already?” quiz from the beginning of the chapter are repeated here to ensure that

you have mastered the chapter’s topic areas. Hopefully, these questions will help limit the

number of exam questions on which you narrow your choices to two options and then guess.

Make sure to use the CD and take the simulated exams.

The answers to these questions can be found in Appendix A, on page 703.

you to issue commands that could be disruptive to router operations?

disruptive commands?

If so, what other purpose can it serve?

“Unknown command, computer name, or host.” Offer an explanation as to why this error

message appears.

command, or is it simply a number of commands, regardless of their size?

execute this command by using command recall keystrokes?

editing keystrokes?

console? What configuration mode context must you be in—that is, what command(s)

must be typed before this command after entering configuration mode? List the

commands in the order in which they must be typed while in config mode.

console? What configuration mode context must you be in—that is, what command(s)

must you type before this command after entering configuration mode? List the

commands in the order in which they must be typed while in config mode.

named c2500-j-l.112-14.bin on TFTP server 128.1.1.1 when the router is reloaded? If you

forgot the first parameter of this command, what steps must you take to learn the correct

parameters and add the command to the configuration? (Assume that you are not logged

in to the router when you start.)

command? Is that password encrypted by default?

banner This is Ivan Denisovich’s Gorno Router—Do Not Use

want to use the configuration parameters you just typed in. Which type of memory is this

configuration stored into if you type yes?

in ROM?

server 128.1.1.1 upon the next reload? Is there more than one way to accomplish this?

file called c4500-d-mz.120-5.bin on TFTP server 128.1.1.1 is copied into Flash memory?

one called c2500-j-l.112-14.bin. Which one does the router use when it boots up? How

could you force the other IOS file to be used? Without looking at the router configuration,

what command could be used to discover which file was used for the latest boot of the

router?

later.)

CDP?

to access a router?

router. Which one is a more recent addition to the IOS?

Which one is a more recent addition to the IOS?

currently used configuration for this router to exactly match what is in the startup

configuration file. Explain.

Compare the following output in Example 2-7 and Example 2-8. Example 2-7 was gathered at

11:00 a.m., 30 minutes earlier than Example 2-8. What can you definitively say happened to

this router during the intervening half hour?

hostname Gorno

!

enable password cisco

!

interface Serial0

ip address 134.141.12.1 255.255.255.0

!

interface Serial1

ip address 134.141.13.1 255.255.255.0

!

interface Ethernet0

ip address 134.141.1.1 255.255.255.0

!

router rip

network 134.141.0.0

!

line con 0

password cisco

login

line aux 0

line vty 0 4

password cisco

login

hostname SouthernSiberia

prompt Gorno

!

enable secret $8df003j56ske92

enable password cisco

!

interface Serial0

ip address 134.141.12.1 255.255.255.0

!

interface Serial1

ip address 134.141.13.1 255.255.255.0

!

interface Ethernet0

ip address 134.141.1.1 255.255.255.0

no cdp enable

order, could have changed the configuration as shown and allowed the prompt to

have?

!

router rip

network 134.141.0.0

!

line con 0

password cisco

login

line aux 0

line vty 0 4

password cisco

Login

the user reloads Nova?

hostname Nova

banner # This is the router in Nova Sibiersk; Dress warmly before entering! #

!

boot system tftp c2500-js-113.bin 134.141.88.3

boot system flash c2500-j-l.111-9.bin

boot system rom

!

enable password cisco

!

interface Serial0

ip address 134.141.12.2 255.255.255.0

!

interface Serial1

ip address 134.141.23.2 255.255.255.0

!

interface TokenRing0

ip address 134.141.2.2 255.255.255.0

!

router rip

network 134.141.0.0

!

line con 0

password cisco

login

line aux 0

line vty 0 4

password cisco

login

Codes: C – connected, S - static, I - IGRP, R - RIP, M – mobile, B – BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E – EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default

U - per-user static route, o – ODR

Gateway of last resort is not set

to 134.141.88.0 and that the file c2500-j-l.111-9.bin is an IOS image in Flash memory.

What IOS do you expect will be loaded now?

134.141.0.0/24 is subnetted, 6 subnets

C 134.141.2.0 is directly connected, TokenRing0

R 134.141.3.0 [120/1] via 134.141.23.3, 00:00:15, Serial1

R 134.141.1.0 [120/1] via 134.141.12.1, 00:00:20, Serial0

C 134.141.12.0 is directly connected, Serial0

R 134.141.13.0 [120/1] via 134.141.12.1, 00:00:20, Serial0

[120/1] via 134.141.23.3, 00:00:15, Serial1

C 134.141.23.0 is directly connected, Serial1

4096K bytes of flash memory sized on embedded flash.

File name/status

0 c2500-j-l.111-3.bin

[682680/4194304 bytes free/total]

hostname Nova

banner # This is the router in Nova Sibiersk; Dress warmly before entering! #

!

boot system tftp c2500-js-113.bin 134.141.88.3

boot system flash c2500-j-l.111-9.bin

!

enable password cisco

!

interface Serial0

ip address 134.141.12.2 255.255.255.0

!

interface Serial1

ip address 134.141.23.2 255.255.255.0

!

interface Ethernet0

ip address 134.141.2.2 255.255.255.0

!

router rip

network 134.141.0.0

!

line con 0

password cisco

login

line aux 0

line vty 0 4

password cisco

login

!

config-register 0x2101

In Scenario 2-1, the following commands were added to the configuration:

The scenario questions’ answers are as follows:

added to the RAM configuration file immediately and are used. In this case, when the

host name “SouthernSiberia,” as the prompt.

Ethernet, CDP messages from Gorno are useless. So, the only effect is to lessen the

overhead on that Ethernet in a very small way.

The answers to the questions in Scenario 2-2 are as follows:

because there is not currently a route to the subnet of which the TFTP server is a part. It

is reasonable to assume that a route would not be learned 2 minutes later when the router

c2500-j-l.111-9.bin, the boot from Flash memory would fail as well, leaving only one

the 134.141.88.0/24 subnet and having c2500-j-l.111-9.bin in Flash memory does not

help.