cwna certified wireless network administrator study guide exam

cwna certified wireless network administrator study guide exam

Wiley Publishing, Inc.

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CWNA ® Certified Wireless

Study Guide

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Wiley Publishing, Inc.

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Acquisitions and Development Editor: Jeff Kellum

Technical Editor: Sam Coyl

Production Editor: Martine Dardignac

Copy Editor: Judy Flynn

Production Manager: Tim Tate

Vice President and Executive Group Publisher: Richard Swadley

Vice President and Executive Publisher: Joseph B Wikert

Vice President and Publisher: Neil Edde

Permissions Editor: Shannon Walters

Media Development Specialist: Kate Jenkins

Book Designers: Judy Fung and Bill Gibson

Compositor: Laurie Stewart, Happenstance Type-O-Rama

Illustrator: Jeffrey Wilson, Happenstance Type-O-Rama

Proofreader: Nancy Riddiough

Indexer: Nancy Guenther

Cover Designer: Ryan Sneed

Copyright © 2006 by Wiley Publishing, Inc., Indianapolis, Indiana

Published simultaneously in Canada

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For general information on our other products and services or to obtain technical support, please contact our Customer Care Department within the U.S at (800) 762-2974, outside the U.S at (317) 572-3993 or fax (317) 572-4002 Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books.

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TRADEMARKS: Wiley, the Wiley logo, and the Sybex logo are trademarks or registered trademarks of John Wiley & Sons, Inc and/or its affiliates, in the United States and other countries, and may not be used without writ- ten permission CWNA and Certified Wireless Network Administrator are trademarks or registered trademarks

of Planet3 Wireless, Inc in the United States and other countries All other trademarks are the property of their respective owners Wiley Publishing, Inc., is not associated with any product or vendor mentioned in this book.

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To Our Valued Readers:

Thank you for looking to Sybex for your CWNA exam prep needs We at Sybex are proud

of our reputation for providing certification candidates with the practical knowledge and skills needed to succeed in the highly competitive IT marketplace Certification candidates have come to rely on Sybex for accurate and accessible instruction on today’s crucial tech-nologies and business skills

Just as Planet3 is committed to establishing measurable standards for certifying IT wireless administration professionals by means of the CWNA certification, Sybex is committed to providing those individuals with the knowledge needed to meet those standards

The authors and editors have worked hard to ensure that this edition of the CWNA:

in-depth, and pedagogically sound We’re confident that this book will exceed the ing standards of the certification marketplace and help you, the CWNA certification candi-date, succeed in your endeavors

demand-As always, your feedback is important to us If you believe you’ve identified an error in the book, please send a detailed e-mail to support@wiley.com And if you have general com-ments or suggestions, feel free to drop me a line directly at nedde@wiley.com At Sybex we’re continually striving to meet the needs of individuals preparing for certification exams Good luck in pursuit of your CWNA certification!

Neil EddeVice President & PublisherWiley Publishing, Inc

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We would like to dedicate this book to our parents, teachers, instructors, and mentors, who have helped us throughout our lives We hope that through this book and through our teaching and mentoring we can help others achieve their goals.

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David Coleman would like to thank his children, Brantley and Carolina, for their patience and understanding of their father throughout the writing of the book I love you kids very much.David Westcott would like to thank his wife, Gina, for her patience, understanding, and support and for the hours she spent reading and editing the book

Writing the CWNA study guide has been a nine-month adventure that neither of us fully grasped from the start We would like to thank all of the following individuals for their sup-port and contributions during the entire process

We must first thank Acquisitions and Developmental Editor Jeff Kellum of Sybex ing for initially finding us and bringing us on to this project Jeff is an extremely patient and understanding editor who, despite our best efforts, needed to send us an occasional nasty e-mail message We would also like to thank Project Editor Martine Dardignac of Wiley Martine was an absolute pleasure to work with despite the fact that we drove her crazy We would also love to thank our copyeditor, Judy Flynn; our proofreader, Nancy Riddiough; the illustrators; and our media development specialist, Shannon Walters

Publish-We need to give a big shout out to our technical editor, Sam Coyle Sam is a member of the IEEE with many years of practical experience in wireless communications His contributions to the book were nothing short of invaluable When Sam is not providing awesome technical edit-

a wireless solutions provider

We would also like to thank Devin Akin, Kevin Sandlin, Scott Turner, and Scott Williams

internation-ally renowned wireless certification program that you have developed It has been a pleasure working with all of you the past four years

the video “Beam Patterns and Polarization of Directional Antennas” on the CD-ROM, and thanks to Andrew Potter for making himself available for our photography needs

Special thanks goes to Andras Szilagyi, not only for creating the EMANIM software gram, but also for all the extra assistance he provided by working with us to create a custom-ized version of the program for the CD-ROM

pro-We would also like to think the following individuals and companies for their contributions

to the book:

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viii Acknowledgments

• Helium Networks—Keith Borden, Ed Finn, and Walt Halasowski

• SpectraLink—Melissa Aguirre, Ray Baum, Wayne McAllister, Wylee Post, and

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Wireless LANs seem to be everywhere these days The technology is advancing so rapidly that

it seems almost impossible to stay abreast of all of the changes The small office/home office (SOHO) sector is adopting new WLAN technologies well before there are ratified amend-ments or interoperability certifications in place for each technology The small/medium busi-ness (SMB) sector is slightly more cautious but often serves as a test bed for many leading-edge technologies The enterprise has adopted 802.11 technology slowly over the last five years, and adoption has often been due to driving factors such as saving money, as with VoWiFi and device tracking technologies, or being able to accomplish new business goals that could not be achieved without wireless technology

Wireless has recently become wildly popular in the enterprise, and vendors are frantically releasing new products into the market With a relentless stream of new technologies and products comes an increased demand for education and certification The CWNP Program is dedicated strictly to staying abreast of all facets of 802.11 technology—with both standards and products The CWNA certification is the first step in the CWNP line of certifications and

is focused on administering an enterprise 802.11 WLAN CWNA includes topics such as 802.11 standards, security, management, protocol analysis, QoS, site surveying, and radio fre-quency Additional certifications focus more intensely on security, protocol analysis, QoS, and

RF spectrum management

David Coleman and David Westcott have worked as Certified Wireless Network Trainers (CWNTs) for as long as the CWNT certification has been available, and each was quick to pursue all CWNP certifications as they were released Each has years of experience with a breadth of WLAN technologies and leading-edge products, which is obvious to their stu-dents and anyone working alongside them in the field Having worked with each of these gentlemen for years, I can confidently say there could be no finer pair of seasoned trainers collaborating on a CWNA book These WLAN veterans have devoted hundreds of hours to pouring their experience into this book, and the reader is assured to acquire a plethora of 802.11 knowledge Mr Coleman and Mr Westcott have participated in the shaping of the CWNP Program as a whole since its earliest days and have each added tremendous value to the CWNA certification specifically I would like to thank each of these fine gentlemen for their unwavering support of the CWNP Program, and I would like to congratulate them

on their diverse accomplishments as engineers, trainers, and now authors

Devin AkinChief Technology OfficerThe CWNP Program

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Contents at a Glance

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International Telecommunication Union

Summary 14

Polarity 26Wavelength 27Frequency 29Amplitude 30Phase 31

Absorption 33Reflection 35Scattering 36Refraction 37Diffraction 38

xii Contents

Transmitter 57Antenna 58Receiver 59

Watt 61

dBi 63dBd 65dBm 65

Cables 118Connectors 119Splitters 120Amplifiers 120Attenuators 121

802.11g 139802.11d 141802.11F 142802.11h 144802.11i 145802.11j 146802.11e 147

802.11k 148802.11m 149802.11n 149802.11p 150802.11r 150802.11s 151

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xiv Contents

802.11T 151802.11u 152802.11v 153802.11w 153Summary 154

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Contents xv

Summary 209

xvi Contents

Authentication 234

Association 237

Roaming 240Reassociation 240Disassociation 241Deauthentication 241Summary 242

Fragmentation 253

RTS/CTS 257CTS-to-Self 260

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Contents xvii

Endspan 298Midspan 298Summary 298

Summary 318

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Encryption 360AAA 360Segmentation 361

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xx Contents

Manual 460Assisted 464Predictive 465

Table of Exercises

Exercise 2.1 Visual Demonstration of Absorption 40

Exercise 2.2 Visual Demonstration of Multipath and Phase 44

Exercise 3.1 Step-by-Step Procedure 67

Exercise 3.2 Rule of 10s and 3s Example 1 69

Exercise 3.3 Rule of 10s and 3s Example 2 70

Exercise 3.4 Rule of 10s and 3s Example 3 73

Exercise 3.5 Rule of 10s and 3s Example 4 75

Exercise 8.1 Frame Analysis 239

Exercise 16.1 Spectrum Analysis 446

Exercise 16.2 Link Budget and Fade Margin 459

Exercise 16.3 Cable Loss Calculations 459

Exercise 16.4 Manual Coverage Analysis 463

Exercise 16.5 Predictive Coverage Analysis 466

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If you have purchased this book or if you are thinking about purchasing this book, then you

Administra-tor) certification exam or in learning more about what the CWNA certification exam is about The authors would like to congratulate you on this first step, and we hope that our book can help you on your journey Wireless networking is currently one of the hottest technologies on the market As with many fast-growing technologies, the demand for knowledgeable people

is often greater than the supply The CWNA certification is one way to prove that you have the knowledge and skills to support this growing industry This study guide was written with that goal in mind

This book was written to help teach you about wireless networking so that you have the knowledge needed to not only pass the CWNA certification test, but to also be able to design, install, and support wireless networks We have included review questions at the end of each chapter to help you test your knowledge and prepare for the test We have also included labs, white papers, videos, and presentations on the CD to further facilitate your learning.Before we tell you about the certification process and requirements, we must mention that this information may have changed by the time you are taking your test We recommend that

objectives and requirements are

Don’t just study the questions and answers! The practice questions in this book are designed to test your knowledge of a concept or objective that is likely to be on the CWNA certification The practice questions will be different than the actual certification questions If you learn and understand the topics and objectives, you will be better prepared for the test

If you have ever prepared to take a certification test for a technology that you are unfamiliar with, you know that you are not only studying to learn a different technology, but you are probably also learning about an industry that you are unfamiliar with Read on and we will

Professional There is no CWNP test CWNP is the umbrella for the certification program that

is offered by Planet3 Wireless, Inc (Planet3) Planet3 is a privately held Georgia (U.S.) pany that created the CWNP certifications and courses The CWNP certification program is

com-a vendor-neutrcom-al progrcom-am

The objective of the CWNP Program is to certify people on wireless networking, not on a specific vendor’s product Yes, at times the authors of this book and the creators of the certi-fication will talk about, demonstrate, or even teach how to use a specific product; however, the goal is the overall understanding of wireless, not the product itself If you learned to drive

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xxiv Introduction

a car, you had to physically sit and practice in one When you think back and reminisce, you probably don’t tell someone you learned to drive a Ford; you probably say you learned to drive using a Ford

There are six wireless certifications offered by the CWNP Program:

Wireless# TM (“wireless sharp”) The Wireless# certification is an entry-level certification ing on Wi-Fi, Bluetooth, WiMAX, ZigBee, RFID, VoWLAN, and infrared wireless networks The Wireless# exam (PW0-050) covers a moderate level of detail on a broad base of wireless technologies

foundation-level Wi-Fi certification; however, it is not considered an “entry-foundation-level” technology certification Individuals taking this exam (exam #PW0-100) typically have a solid grasp on network basics such as the OSI model, IP addressing, PC hardware, and network operating systems Many of these candidates already hold other industry-recognized certifications, such as the CompTIA Net-work+ or Cisco CCNA, and are looking for the CWNA certification to enhance or complement existing skills

is focused on standards-based wireless security protocols, security policy, and secure wireless network design This certification introduces candidates to many of the technologies and tech-niques that intruders use to compromise wireless networks and administrators use to protect wireless networks With recent advances in wireless security, WLANs can be secured beyond their wired counterparts

measures your ability to analyze and troubleshoot wireless LANs Before taking the exam, you should understand the frame structures and exchange processes for each of the 802.11 series

of standards and how to use the tools that are available for analyzing and troubleshooting today’s wireless LANs

WLAN analysis, design, troubleshooting, quality of service (QoS) mechanisms, spectrum agement, and extensive knowledge of the IEEE 802.11 standard as amended This certification

man-is the pinnacle of the WLAN certification industry, and the exam man-is sure to be demanding

qual-ified instructors certqual-ified by the CWNP Program to deliver CWNP training courses to IT sionals CWNTs are technical and instructional experts in wireless technologies, products, and solutions To ensure a superior learning experience for our customers, CWNP Education Partners are required to use CWNTs when delivering training using Official CWNP Courseware

profes-Effective January 1, 2007, all material from the existing CWAP exam will be integrated into the CWNE certification.

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Introduction xxv

How to Become a CWNA

To become a CWNA, you must do the following two things: agree that you have read and will abide by the terms and conditions of the CWNP Confidentiality Agreement, and pass the CWNA certification test

A copy of the CWNP Confidentiality Agreement can be found online at the CWNP website.

When you sit to take the test, you will be required to accept this confidentiality agreement before you can continue with the test Once you have agreed, you will be able to continue with the test, and if you pass the test, you are then a CWNA

The information for the exam is as follows:

When you schedule the exam, you will receive instructions regarding appointment and cellation procedures, ID requirements, and information about the testing center location In addition, you’ll receive a registration and payment confirmation letter Exams can be sched-uled weeks in advance or, in some cases, even as late as the same day

can-After you have successfully passed the CWNA exam, the CWNP Program will award you a certification that is good for three years To recertify, you will need to pass the current PW0-100 exam, the CWSP exam, or the CWNE exam If the information you provided the testing center

is correct, you will receive an e-mail from CWNP recognizing your accomplishment and ing you with a CWNP certification number After you earn any CWNP certification, you can request a certification kit The kit includes a congratulatory letter, a certificate, and a wallet-sized personalized ID card You will need to log in to the CWNP tracking system, verify your contact information, and request your certification kit

provid-Who Should Buy This Book?

If you want to acquire a solid foundation in wireless networking and your goal is to prepare for the exam, this book is for you You will find clear explanations of the concepts you need

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xxvi Introduction

to grasp and plenty of help to achieve the high level of professional competency you need in order to succeed

If you want to become certified as a CWNA, this book is definitely what you need However,

if you just want to attempt to pass the exam without really understanding wireless, this study guide isn’t for you It’s written for people who want to acquire hands-on skills and in-depth knowledge of wireless networking

How to Use This Book and the CD

We’ve included several testing features in the book and on the CD-ROM These tools will help you retain vital exam content as well as prepare to sit for the actual exam

Before You Begin At the beginning of the book (right after this introduction) is an assessment test you can use to check your readiness for the exam Take this test before you start reading the book; it will help you determine the areas you may need to brush up on The answers to the assessment test appear on a separate page after the last question of the test Each answer includes

an explanation and a note telling you the chapter in which the material appears

are review questions at the end of each chapter As you finish each chapter, answer the review questions and then check your answers—the correct answers appear on the page following the last review question You can go back to reread the section that deals with each question you got wrong to ensure that you answer correctly the next time you’re tested on the material

Electronic Flashcards You’ll find flashcard questions on the CD for on-the-go review These are short questions and answers, just like the flashcards you probably used in school You can answer them on your PC or download them onto a Palm device for quick and convenient reviewing

can identify weak areas up front and then develop a solid studying strategy that includes each

of the robust testing features described previously Our thorough readme file will walk you through the quick, easy installation process

In addition to the assessment test and the chapter review questions, you’ll find two sample exams Use the test engine to take these practice exams just as if you were taking the actual exam (without any reference material) When you’ve finished the first exam, move on to the next one to solidify your test-taking skills If you get more than 95 percent of the answers cor-rect, you’re ready to take the certification exam

for-mat so you can easily read it on any computer If you have to travel but still need to study for the exam, and you have a laptop with a CD-ROM drive, you can carry this entire book with you

Labs and Exercises Several chapters in this book have labs that use software, spreadsheets, and videos that are also provided on the CD-ROM that is included with this book These labs and exercises will provide you with a broader learning experience by providing hands-

on experience and step-by-step problem solving

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Introduction xxvii

Exam Objectives

The CWNA exam measures your understanding of the fundamentals of RF behavior, your ity to describe the features and functions of wireless LAN components, and your knowledge of the skills needed to install, configure, and troubleshoot wireless LAN hardware peripherals and protocols

abil-The skills and knowledge measured by this examination are derived from a survey of wireless networking experts and professionals The results of this survey were used in weighing the subject areas and ensuring that the weighting is representative of the relative importance of the content.The following chart provides the breakdown of the exam, showing you the weight of each section:

Radio Frequency (RF) Technologies—21%

1.3 RF Signal and Antenna Concepts

1.3.1 Identify RF signal characteristics, the applications of basic RF antenna concepts, and the implementation of solutions that require RF antennas

802.11 Regulations and Standards—12%

2.1 Spread Spectrum Technologies

2.1.1 Identify some of the uses for spread spectrum technologies

2.3 802.11 Industry Organizations and Their Roles

2.3.1 Define the roles of the following organizations in providing direction, cohesion, and accountability within the wireless LAN industry

 FCC

 IEEE

Introduction xxxi

802.11 Protocols and Devices—14%

3.1 802.11 Protocol Architecture

3.1.1 Summarize the processes involved in authentication and association

3.1.2 Define, describe, and apply the following concepts associated with wireless LAN service sets

3.2 802.11 MAC andPHY Layer Technologies

3.2.1 Describe and apply the following concepts surrounding wireless LAN frames

3.2.2 Identify methods described in the 802.11 standard for locating, joining, and taining connectivity with an 802.11 wireless LAN

3.2.3 Define, describe, and apply 802.11 modes and features available for moving data traffic across the RF medium

xxxii Introduction

3.3 Wireless LAN Infrastructure and Client Devices

3.3.1 Identify the purpose of the following wireless LAN infrastructure devices and describe how to install, configure, secure, and manage them

3.3.2 Describe the purpose of the following wireless LAN client devices and explain how

to install, configure, secure, and manage them

802.11 Network Implementation—21%

4.1 802.11 Network Design, Implementation, and Management

4.1.1 Identify technology roles for which wireless LAN technology is appropriate

Introduction xxxiii

5.1 802.11 Network Security Architecture

5.1.1 Identify and describe the strengths, weaknesses, appropriate uses, and appropriate implementation of the following 802.11 security-related items

5.2 802.11 Network Security Analysis Systems, Devices

5.2.1 Identify the purpose and features of the following wireless analysis systems and explain how to install, configure, integrate, and manage them as applicable

5.3 802.11 Network Security Policy Basics

5.3.1 Describe the following general security policy elements

6.1 802.11 Network Site Survey Fundamentals

6.1.1 Explain the importance and processes involved in conducting a complete RF site survey

6.1.2 Explain the importance of and proprietary documentation involved in preparing for an RF site survey

6.1.3 Explain the technical aspects and information collection procedures involved in an

RF site survey

6.1.4 Describe site survey reporting procedures

xxxvi Introduction

6.2 802.11 Network Site Survey Systems and Devices

6.2.1 Identify the equipment, applications, and system features involved in performing automated site surveys

6.2.2 Identify the equipment and applications involved in performing manual site surveys

Tips for Taking the CWNA Exam

Here are some general tips for taking your exam successfully:

other can be a major credit card or a passport Both forms must include a signature

partic-ularly tables and lists of exam-related information

you know exactly what the question is asking

cor-rect answer, a message at the bottom of the screen will prompt you to either “choose two”

or “choose all that apply.” Be sure to read the messages displayed to know how many rect answers you must choose

elimi-nation to get rid of the obviously incorrect answers first Doing so will improve your odds

if you need to make an educated guess

can-not move forward and backward through the exam You must answer the current tion before you can move to the next question, and once you have moved to the next question, you cannot go back and change an answer on a previous question

an average of 90 seconds to answer each question You can spend as much or as little time

on any one question, but when 90 minutes is up, the test is over Check your progress After

45 minutes, you should have answered at least 30 questions If you have not, don’t panic

Introduction xxxvii

You will need to simply answer the remaining questions at a faster pace If on average you can answer each of the remaining 30 questions 4 seconds quicker, you will recover 2 min-utes Again, don’t panic; just pace yourself

website at www.cwnp.com

About the Authors

David D Coleman is a wireless security/networking trainer and consultant He teaches the CWNP classes that are recognized throughout the world as the industry standard for wireless networking certification and he also conducts vendor-specific Wi-Fi training He has also taught numerous

“train-the-trainer” classes and “beta” classes for the CWNP program David has instructed IT professionals from around the globe in wireless networking administration, wireless security, and wireless frame analysis His company, AirSpy Networks (www.airspy.com), specializes in corpo-rate training and has worked in the past with SpectraLink and Dell Computers and Air Defense AirSpy Networks also specializes in government classes and has trained numerous computer secu-rity employees from various law enforcement agencies, the U.S Marines, the U.S Army, the U.S Navy, and other federal and state government agencies David resides in Atlanta, Georgia, where he shares a home with his two teenage children, Carolina and Brantley, and his dog,

Bo the WonderPuppy He can be reached via e-mail at david@airspy.com

David Westcott is an independent consultant and technical trainer with over 20 years of experience in information technology, specializing in computer networking and security In addition to providing consulting advice and direction to his corporate clients, David has been

a certified trainer for over 12 years, providing training to government agencies, corporations, and universities David was an adjunct faculty member for Boston University’s Corporate Edu-cation Center for over 10 years David has developed courseware for Boston University and many other clients in the areas of networking and security

Since installing his first wireless network in 1999, David has become a Certified Wireless Network Trainer, Administrator, Security Professional, and Analysis Professional David has consulted with Planet3 Wireless, providing content and technical editing for the Planet3 Wire-less courseware used in the CWNP wireless certification programs David has also earned cer-tifications from Cisco, Microsoft, EC-Council, CompTIA, and Novell David lives in Concord, Massachusetts, with his wife, Gina In his spare time, David is a licensed pilot and enjoys flying places with his wife He can be reached via e-mail at david@westcott-consulting.com