CWNA Certified Wireless Network Administrator Study Guide E-Book

David D. Coleman

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1639

Veröffentlichungsjahr: 2018

Beschreibung

The bestselling CWNA study guide, updated for the latest exam The CWNA: Certified Wireless Network Administrator Study Guide is the ultimate preparation resource for the CWNA exam. Fully updated to align with the latest version of the exam, this book features expert coverage of all exam objectives to help you internalize essential information. A pre-assessment test reveals what you already know, allowing you to focus your study time on areas in need of review, while hands-on exercises allow you to practice applying CWNA concepts to real-world scenarios. Expert-led discussion breaks complex topics down into easily-digestible chucks to facilitate clearer understanding, and chapter review questions help you gauge your progress along the way. You also get a year of free access to the Sybex online interactive learning environment, which features additional resources and study aids including bonus practice exam questions. The CWNA exam tests your knowledge of regulations and standards, protocols and devices, network implementation, security, and RF site surveying. Thorough preparation gives you your best chance of passing, and this book covers it all with a practical focus that translates to real on-the-job skills. * Study 100% of the objectives for Exam CWNA-107 * Assess your practical skills with hands-on exercises * Test your understanding with challenging chapter tests * Access digital flashcards, white papers, bonus practice exams, and more The CWNA certification is a de facto standard for anyone working with wireless technology. It shows employers that you have demonstrated competence in critical areas, and have the knowledge and skills to perform essential duties that keep their wireless technology functioning and safe. The CWNA: Certified Wireless Network Administrator Study Guide gives you everything you need to pass the exam with flying colors.

Leseprobe

CWNA® Certified WirelessNetwork Administrator

Study GuideExam CWNA-107

Fifth Edition

David D. Coleman, CWNE #4

David A. Westcott, CWNE #7

Senior Acquisitions Editor: Kenyon Brown

Development Editor: Kim Wimpsett

Technical Editor: Ben Wilson

Production Manager: Kathleen Wisor

Copy Editor: John Sleeva

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Copyright © 2018 by John Wiley & Sons, Inc., Indianapolis, Indiana

Published simultaneously in Canada

ISBN: 978-1-119-42578-6

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ISBN: 978-1-119-47750-1 (ebk.)

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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 written permission. CWNA is a registered trademark of CWNP, LLC.\ All other trademarks are the property of their respective owners. John Wiley & Sons, Inc. is not associated with any product or vendor mentioned in this book.

“An investment in knowledge always pays the best interest.”

Benjamin Franklin, one of the Founding Fathers of the United States.

Almost fifteen years ago, we were approached by our publisher to co-author a study guide for the Certified Wireless Network Administrator (CWNA) certification exam. At the time, the phrase “Wi-Fi” was only a few years old and had yet to become ingrained into our culture. 802.11g technology had begun to emerge and we were so excited by the blazing speeds of 54 Mbps available on the 2.4 GHz frequency band. We agreed to author the book. Five editions later, 802.11 WLAN technology has drastically evolved and Wi-Fi is now an integral part of our day-to-day lives.

The CWNA certification has long been recognized as the foundation-level certification for network professionals looking to validate their knowledge of 802.11 WLAN technology. As authors, we have been humbled by the tens of thousands of individuals who have purchased the CWNA Study Guide to assist in their pursuit of the CWNA certification. We are also humbled that many universities and colleges have selected the book as part of their curriculum for wireless technology classes. In our travels, we have met and become friends with many of our readers of the past four editions of the book. We discovered that a large number of people who purchase the book use it as a reference guide in the workplace and not just as a study guide. We have also had many people tell us that the book has helped them advance in their Wi-Fi careers. Once again, we are very humbled, and we would like to dedicate the 5th edition of the CWNA Study Guide to our readers.

Our goal has always been to educate as many people as possible about WLAN technology. If you are a newcomer to 802.11 wireless networking, we hope this book will be your first investment in Wi-Fi knowledge. If you are a veteran WLAN professional, we hope that when you are done reading this book, you will pass it along to a friend or a colleague. Sharing the Wi-Fi knowledge will be a sound investment.

Sincerely,

David Coleman and David Westcott

Acknowledgments

When we wrote the first edition of the CWNA Study Guide, David Coleman's children, Brantley and Carolina, were young teenagers. Carolina now holds a master's degree in public policy from the University of Southern California (USC). Brantley graduated from Boston University and recently earned his Ph.D. in biochemistry at the University of Washington. David would like to thank his now adult children for years of support and for making their dad very proud. David would also like to thank his mother, Marjorie Barnes, stepfather, William Barnes, and brother, Rob Coleman, for many years of support and encouragement. David also thanks Valla Ann for being so special and making him laugh sideways.

David Coleman would also like to thank his friends and family at Aerohive Networks (www.aerohive.com). There are many past and present Aerohive employees he would like to thank, but there simply is not enough room. So thank you to all of his Aerohive co-workers. It has been one wild ride the past nine years!

David Westcott would like to thank Janie and Savannah for the smiles and hugs he receives when arriving home after being away delivering a training class. He would also like to thank Janie for her patience and understanding of his travel and writing demands.

David Westcott also would like to thank the training department at Aruba Networks. In 2004 Aruba Networks hired him as their first contract trainer. Much has changed over the years, but it is still a fun and exciting journey.

Writing CWNA: Certified Wireless Network Administrator Study Guide has once again been an adventure. We would like to thank the following individuals for their support and contributions during the entire process.

We must first thank Sybex acquisitions editor Jim Minatel for reaching out to us and encouraging us to write this fifth edition of our book. We would also like to thank our development editor, Kim Wimpsett, who has been a pleasure to work with on multiple book projects. We also need to send special thanks to our editorial manager, Pete Gaughan; our production editor, Katie Wisor; and John Sleeva, our copyeditor.

We also need to give a big shout-out to our technical editor, Ben Wilson of Fortinet (www.fortinet.com). Ben has accumulated years of Wi-Fi experience working for three major WLAN vendors. The feedback and input provided by Ben was invaluable.

Special thanks must also go out to both Andrew vonNagy, CWNE #84, and Marcus Burton, CWNE #78, for their expertise as technical editors in earlier editions of the book.

Andrew Crocker has again provided us with wonderful photographs and some amazing editing of some not so wonderful photographs that we provide him. You can see much more of his work and talent at www.andrew-crocker.com.

Thanks to Proxim and to Ken Ruppel ([email protected]) for allowing us to include the video Beam Patterns and Polarization of Directional Antennas with the book's online resources, which can be accessed at www.wiley.com/go/cwnasg.

Special thanks goes to Andras Szilagyi, not only for creating the EMANIM software program but for all the extra assistance he provided over the past thirteen years by creating customized versions of the program for the different editions of the book. You can reach Andras at www.szialab.org.

Thanks to Chris DePuy of the technology research firm, 650 Group (www.650.group.com), for the WLAN industry trend analysis.

Very special thanks to Marco Tisler, CWNE #126, for his content contribution about APIs. Thank you to Chris Harkins for his content about cloud networking. Thanks to Gregor Vucajnk, CWNE #96, for his copy regarding LTE. Thanks to Karl Benedict for his input and content about directional antennas. Thanks to Perry Correll for his input regarding 802.11ax.

Most gracious appreciation to Rick Murphy, CWNE #10, for his content regarding future 5 GHz U-NII bands. Rick offers some outstanding WLAN training resources at howwirelessworks.com.

We need to send thanks to Joel Crane, CWNE #233, of both MetaGeek and Ekahau fame for his contributions and the spectrum analyzer screenshots.

Very special thanks to Adrian Granados for all of his contributions to the wireless community. Be sure and check out his cool Wi-Fi applications at www.adriangranados.com.

Several other WLAN rock stars that are mentioned in the copy of this book: Mike Albano, CWNE #150; Eddie Forero, CWNE #160; James Garringer, CWNE #179; Jerome Henry, CWNE #45; and François Vergès, CWNE #180.

We would also like to thank the following individuals and companies for their support and contributions to the book:

Devin Akin, CWNE #1, of Divergent Dynamics (www.divergentdynamics.com).

Dennis Burrell, Product Innovation Technologist, and Tauni Odia, Marketing Manager of Ventev (www.ventev.com).

Kelly Burroughs, Product Marketing Manager of iBwave (www.ibwave.com).

Mike Cirello, Co-Founder of HiveRadar (www.hiveradar.com).

Jaime Fábregas Fernández, R&D Manager of Tarlogic Research S.L. (www.acrylicwifi.com).

Tina Hanzlik, Director, Marketing Communications at the Wi-Fi Alliance (www.wi-fi.org).

James Kahkoska, CTO - Handheld Network Test, and Julio Petrovitch, Principal Technical Marketing Engineer, Netscout (www.netscout.com).

Brian Long, CWNE #159, Senior Director, Global Professional Services at Masimo (www.masimo.com).

Bruce Miller, VP, Product Marketing, Riverbed Technology (www.riverbed.com).

Jerry Olla, CWNE #238, Technical Solutions Architect, and Jussi Kiviniemi, Senior VP of Ekahau (www.ekahau.com).

Scott Thompson, President of Oberon, Inc. (www.oberoninc.com).

Ryan Woodings, Founder, and Peter Vomocil, CMO of MetaGeek (www.metageek.com).

We also need to thank Keith Parsons, CWNE #3, and his team at wirelessLAN Professionals. Keith has built a worldwide community of WLAN experts that share knowledge. You can learn more about the wirelessLAN Professionals conferences at www.wlanpros.

We would also like to thank, Tom Carpenter, CWNE #104, of the CWNP program (www.cwnp.com). All CWNP employees, past and present, should be proud of the internationally renowned wireless certification program that sets the education standard within the enterprise Wi-Fi industry. It has been a pleasure working with all of you for the past two decades.

Finally, we would like to thank Chuck Lukaszewski, CWNE #112, for his gracious foreword that he wrote for this book.

About the Authors

David D. Coleman is the Senior Product Evangelist for Aerohive Networks (www.aerohive.com). David collaborates with the Aerohive Marketing team and travels the world for WLAN training sessions and speaking events. He has instructed IT professionals from around the globe in WLAN design, security, administration, and troubleshooting. David has written multiple books, blogs, and white papers about wireless networking, and he is considered an authority on 802.11 technology. Prior to working at Aerohive, he specialized in corporate and government Wi-Fi training and consulting. In the past, he has provided WLAN training for numerous private corporations, the US military, and other federal and state government agencies. When he is not traveling, David resides in Atlanta, Georgia. David is CWNE #4, and he can be reached via email at [email protected]. Please follow David on Twitter: @mistermultipath.

David Westcott is an independent consultant and technical trainer with more than 32 years of experience. David has been a certified trainer for more than 25 years, and specializes in wireless networking, wireless management and monitoring, and network access control. He has provided training to thousands of students at government agencies, corporations, and universities in more than 30 countries around the world. David was an adjunct faculty member for Boston University's Corporate Education Center for more than 10 years. David has written multiple books as well as numerous white papers, and has developed many courses on wired and wireless networking technologies and networking security.

David was a member of the original CWNE Roundtable. David is CWNE #007 and has earned certifications from many companies, including Aruba Networks, Cisco, Microsoft, Ekahau, EC-Council, CompTIA, and Novell. David lives in Concord, Massachusetts with his wife Janie. David can be reached via email at [email protected]. Please follow David on Twitter: @davidwestcott.

CONTENTS

Acknowledgments

About the Authors

Table of Exercises

Foreword

Introduction

CWNA Exam (CWNA-107) Objectives

CWNA: Certified Wireless Network Administrator Exam (CWNA-107) Objectives

Assessment Test

Answers to the Assessment Test

Chapter 1 Overview of Wireless Standards, Organizations, and Fundamentals

History of Wireless Local Area Networks

Standards Organizations

Core, Distribution, and Access

Communications Fundamentals

Summary

Exam Essentials

Review Questions

Chapter 2 IEEE 802.11 Standard and Amendments

Original IEEE 802.11 Standard

IEEE 802.11-2016 Ratified Amendments

Post 802.11-2016 Ratified Amendments

IEEE 802.11 Draft Amendments

Defunct Amendments

IEEE Task Group m

Summary

Exam Essentials

Review Questions

Chapter 3 Radio Frequency Fundamentals

What Is a Radio Frequency Signal?

Radio Frequency Characteristics

Radio Frequency Behaviors

Summary

Exam Essentials

Review Questions

Chapter 4 Radio Frequency Components, Measurements, and Mathematics

RF Components

Units of Power and Comparison

RF Mathematics

Summary

Exam Essentials

Review Questions

Chapter 5 Radio Frequency Signal and Antenna Concepts

Azimuth and Elevation Charts (Antenna Radiation Envelopes)

Interpreting Polar Charts

Beamwidth

Antenna Types

Visual Line of Sight

RF Line of Sight

Fresnel Zone

Earth Bulge

Antenna Polarization

Antenna Diversity

Multiple-Input, Multiple-Output

Antenna Connection and Installation

Antenna Accessories

Regulatory Compliance

Summary

Exam Essentials

Review Questions

Chapter 6 Wireless Networks and Spread Spectrum Technologies

Narrowband and Spread Spectrum

Frequency-Hopping Spread Spectrum

Direct-Sequence Spread Spectrum

Orthogonal Frequency-Division Multiplexing

Industrial, Scientific, and Medical Bands

Unlicensed National Information Infrastructure Bands

3.6 GHz Band

4.9 GHz Band

Future Wi-Fi Frequencies

2.4 GHz Channels

5 GHz Channels

Adjacent, Nonadjacent, and Overlapping Channels

Throughput vs. Bandwidth

Communication Resilience

Summary

Exam Essentials

Review Questions

Chapter 7 Wireless LAN Topologies

Wireless Networking Topologies

802.11 Stations

802.11 Service Sets

802.11 Configuration Modes

Summary

Exam Essentials

Review Questions

Chapter 8 802.11 Medium Access

CSMA/CA vs. CSMA/CD

Collision Detection

Distributed Coordination Function

Point Coordination Function

Hybrid Coordination Function

Wi-Fi Multimedia

Airtime Fairness

Summary

Exam Essentials

Review Questions

Chapter 9 802.11 MAC

Packets, Frames, and Bits

Data-Link Layer

Physical Layer

802.11 and 802.3 Interoperability

802.11 MAC Header

802.11 Frame Body

802.11 Trailer

802.11 State Machine

Management Frames

Control Frames

Data Frames

Power Management

Summary

Exam Essentials

Review Questions

Chapter 10 MIMO Technology: HT and VHT

MIMO

Multi-User MIMO

Channels

Guard Interval

256-QAM Modulation

802.11n/ac PPDUs

802.11n/ac MAC

HT/VHT Protection Mechanisms

Wi-Fi Alliance Certification

Summary

Exam Essentials

Review Questions

Chapter 11 WLAN Architecture

WLAN Client Devices

Management, Control, and Data Planes

WLAN Architecture

Specialty WLAN Infrastructure

Cloud Networking

Infrastructure Management

Application Programming Interface

Summary

Exam Essentials

Review Questions

Chapter 12 Power over Ethernet (PoE)

History of PoE

An Overview of PoE Devices

Planning and Deploying PoE

802.11ac and PoE

Summary

Exam Essentials

Review Questions

Chapter 13 WLAN Design Concepts

WLAN Coverage Design

Roaming Design

Channel Design

Capacity Design

Voice vs. Data

Dual 5 GHz and Software-Defined Radios

Physical Environment

Antennas

Outdoor Design

Summary

Exam Essentials

Review Questions

Chapter 14 Site Survey and Validation

WLAN Site Survey and Design Interview

Vertical Market Considerations

Legacy AP-on-a-Stick Survey

Hybrid Survey

Validation Survey

Site Survey Tools

Documents and Reports

Summary

Exam Essentials

Review Questions

Chapter 15 WLAN Troubleshooting

Five Tenets of WLAN Troubleshooting

Layer 1 Troubleshooting

Layer 2 Troubleshooting

Security Troubleshooting

Roaming Troubleshooting

Channel Utilization

Layers 3–7 Troubleshooting

WLAN Troubleshooting Tools

Summary

Exam Essentials

Review Questions

Chapter 16 Wireless Attacks, Intrusion Monitoring, and Policy

Wireless Attacks

Intrusion Monitoring

Wireless Security Policies

Summary

Exam Essentials

Review Questions

Chapter 17 802.11 Network Security Architecture

802.11 Security Basics

Legacy 802.11 Security

Robust Security

Traffic Segmentation

WPA3

VPN Wireless Security

Summary

Exam Essentials

Review Questions

Chapter 18 Bring Your Own Device (BYOD) and Guest Access

Mobile Device Management

Self-Service Device Onboarding for Employees

Guest WLAN Access

Hotspot 2.0 and Passpoint

Network Access Control

Summary

Exam Essentials

Review Questions

Chapter 19 802.11ax: High Efficiency (HE)

HE Overview

Multi-User

OFDMA

MU-MIMO

BSS Color

Target Wake Time

Additional 802.11ax PHY and MAC Capabilities

802.11ax Design Considerations

Summary

Review Questions

Chapter 20 WLAN Deployment and Vertical Markets

Deployment Considerations for Commonly Supported WLAN Applications and Devices

Corporate Data Access and End-User Mobility

Network Extension to Remote Areas

Bridging: Building-to-Building Connectivity

Wireless ISP: Last-Mile Data Delivery

Small Office/Home Office

Mobile Office Networking

Branch Offices

Educational/Classroom Use

Industrial: Warehousing and Manufacturing

Retail

Healthcare

Municipal Networks

Hotspots: Public Network Access

Stadium Networks

Transportation Networks

Law Enforcement Networks

First-Responder Networks

Managed Service Providers

Fixed Mobile Convergence

WLAN and Health

Internet of Things

WLAN Vendors

Summary

Exam Essentials

Review Questions

Appendix A Answers to Review Questions

Chapter 1: Overview of Wireless Standards, Organizations, and Fundamentals

Chapter 2: IEEE 802.11 Standard and Amendments

Chapter 3: Radio Frequency Fundamentals

Chapter 4: Radio Frequency Components, Measurements, and Mathematics

Chapter 5: Radio Frequency Signal and Antenna Concepts

Chapter 6: Wireless Networks and Spread Spectrum Technologies

Chapter 7: Wireless LAN Topologies

Chapter 8: 802.11 Medium Access

Chapter 9: 802.11 MAC

Chapter 10: MIMO Technology: HT and VHT

Chapter 11: WLAN Architecture

Chapter 12: Power over Ethernet (PoE)

Chapter 13: WLAN Design Concepts

Chapter 14: Site Survey and Validation

Chapter 15: WLAN Troubleshooting

Chapter 16: Wireless Attacks, Intrusion Monitoring, and Policy

Chapter 17: 802.11 Network Security Architecture

Chapter 18: Bring Your Own Device (BYOD) and Guest Access

Chapter 19: 802.11ax: High Efficiency (HE)

Chapter 20: WLAN Deployment and Vertical Markets

Appendix B Abbreviations and Acronyms

Certifications

Organizations and Regulations

Measurements

Technical Terms

Index

Advert

End User License Agreement

List of Tables

Chapter 1

Table 1.1

Chapter 2

Table 2.1

Chapter 3

Table 3.1

Table 3.2

Chapter 4

Table 4.1

Table 4.2

Table 4.3

Table 4.4

Table 4.5

Chapter 5

Table 5.1

Table 5.2

Chapter 6

Table 6.1

Table 6.2

Table 6.3

Table 6.4

Chapter 8

Table 8.1

Table 8.2

Chapter 9

Table 9.1

Table 9.2

Table 9.3

Chapter 10

Table 10.1

Table 10.2

Table 10.3

Table 10.4

Table 10.5

Table 10.6

Table 10.7

Table 10.8

Chapter 12

Table 12.1

Table 12.2

Table 12.3

Table 12.4

Table 12.5

Table 12.6

Chapter 13

Table 13.1

Table 13.2

Table 13.3

Table 13.4

Chapter 17

Table 17.1

Table 17.2

Table 17.3

Chapter 18

Table 18.1

Chapter 19

Table 19.1

Table 19.2

Table 19.3

Table 19.4

List of Illustrations

Chapter 1

Figure 1.1 Growth of the Wi-Fi industry

Figure 1.2 ISOC hierarchy

Figure 1.3 Wi-Fi logo

Figure 1.4 Wi-Fi Interoperability Certificate

Figure 1.5 The seven layers of the OSI model

Figure 1.6 The wavelength and amplitude of a wave

Figure 1.7 Two waves that are identical but 90 degrees out of phase with each other

Figure 1.8 An example of amplitude-shift keying (ASCII code of an uppercase

K

)

Figure 1.9 An example of frequency-shift keying (ASCII code of an uppercase

K

)

Figure 1.10 An example of phase-shift keying (ASCII code of an uppercase

K

)

Figure 1.11 An example of multiple phase-shift keying (ASCII code of an uppercase

K

)

Chapter 2

Figure 2.1 802.11d settings

Figure 2.2 Mesh points, mesh APs, and mesh portal

Figure 2.3 Seamless roaming

Chapter 3

Figure 3.1 Electromagnetic spectrum

Figure 3.2 A sine wave

Figure 3.3 Wavelength

Figure 3.4 750 KHz wavelength and 252 GHz wavelength

Figure 3.5 2.45 GHz wavelength and 5.775 GHz wavelength

Figure 3.6 Wavelength formulas

Figure 3.7 Frequency

Figure 3.8 Amplitude

Figure 3.9 Phase relationships

Figure 3.10 Propagation analogy

Figure 3.11 Reflection analogy

Figure 3.12 Scattering analogy

Figure 3.13 Refraction

Figure 3.14 Diffraction analogy

Figure 3.15 Multipath

Figure 3.16 RF signal measurement tools

Chapter 4

Figure 4.1 RF components

Figure 4.2 Signal-to-noise ratio

Figure 4.3 Link budget components

Figure 4.4 Point-to-point link budget gain and loss

Figure 4.5 Office link budget gain and loss

Chapter 5

Figure 5.1 Azimuth and elevation charts

Figure 5.2 Omnidirectional antenna: 3-dimensional view

Figure 5.3 Logarithmic/linear comparison

Figure 5.4 Omnidirectional polar chart (E-plane) 

Figure 5.5 Directional polar chart (E-plane) 

Figure 5.6 Antenna beamwidth

Figure 5.7 Beamwidth calculation

Figure 5.8 Vertical radiation patterns of omnidirectional antennas

Figure 5.9 Half-wave dipole antenna

Figure 5.10 Improperly installed omnidirectional antenna

Figure 5.11 The exterior of a patch antenna and the internal antenna element

Figure 5.12 The exterior of a Yagi antenna and the internal antenna element

Figure 5.13 Radiation pattern of a typical semidirectional panel antenna

Figure 5.14 Grid antenna 

Figure 5.15 Dynamic beamforming—adaptive antenna array

Figure 5.16 Fresnel zone

Figure 5.17 Fresnel zone clearances of 60 percent and 100 percent

Figure 5.18 Point-to-point communication with potential obstacle

Figure 5.19 Calculating antenna height

Figure 5.20 NEMA enclosure 

Figure 5.21 Coaxial cable attenuation

Chapter 6

Figure 6.1 Overlay of narrowband and spread spectrum frequency use

Figure 6.2 Multipath diagram

Figure 6.3 FHSS components

Figure 6.4 802.11a/g Channels and OFDM subcarriers

Figure 6.5 Subcarrier signal overlay

Figure 6.6 16-QAM constellation diagram

Figure 6.7 U-NII bands

Figure 6.8 2.4 GHz channel overlay diagram

Figure 6.9 802.11/b/g/n center frequencies

Figure 6.10 IEEE 802.11b transmit spectrum mask

Figure 6.11 Sideband carrier frequency interference

Figure 6.12 U-NII channels

Figure 6.13 U-NII channel overview

Figure 6.14 U-NII 40 MHz, 80 MHz, and 160 MHz channels

Figure 6.15 Potential 20 MHz, 40 MHz, 80 MHz, and 160 MHz channels

Figure 6.16 OFDM spectrum mask

Chapter 7

Figure 7.1 Distribution system medium

Figure 7.2 Wireless distribution system—mesh backhaul

Figure 7.3 Wireless distribution system—WLAN bridge backhaul

Figure 7.4 Service set identifier

Figure 7.5 Basic service set

Figure 7.6 Basic service area

Figure 7.7 Basic service set identifier

Figure 7.8 Incremental BSSID addresses

Figure 7.9 Multiple basic service set identifiers (BSSIDs)

Figure 7.10 Extended service set, seamless roaming

Figure 7.11 Extended service set, nomadic roaming

Figure 7.12 SSID and BSSIDs within an ESS

Figure 7.13 Independent basic service set

Figure 7.14 Mesh basic service set

Figure 7.15 Access point configuration modes

Figure 7.16 Client station configuration modes

Chapter 8

Figure 8.1 Unicast acknowledgment

Figure 8.2 Clear channel assessment (CCA)

Figure 8.3 Duration/ID field

Figure 8.4 Duration value of SIFS + ACK

Figure 8.5 Virtual carrier sense

Figure 8.6 Pseudo-random backoff timer

Figure 8.7 Example of exponential increase of the contention window (CW)

Figure 8.8 SIFS and DIFS

Figure 8.9 EDCA and 802.1D priority tags

Figure 8.10 WMM access category timing

Figure 8.11 Airtime fairness example

Chapter 9

Figure 9.1 802.11 MPDU

Figure 9.2 Data-Link and Physical layers

Figure 9.3 802.11 MAC header

Figure 9.4 Frame Control field

Figure 9.5 Type and Subtype fields

Figure 9.6 Retry field

Figure 9.7 802.11 MAC addressing

Figure 9.8 To DS:0 From DS:0 (Probe request)

Figure 9.9 To DS:0 From DS:0 (Probe response)

Figure 9.10 To DS:1 From DS:0 – Downlink traffic

Figure 9.11 To DS:1 From DS:0 – Uplink traffic

Figure 9.12 To DS:1 From DS:1 – Mesh backhaul

Figure 9.13 To DS:1 From DS:1 – WLAN bridge link

Figure 9.14 Fragmentation

Figure 9.15 Frame check sequence

Figure 9.16 802.11 state machine

Figure 9.17 Passive scanning

Figure 9.18 Active scanning—null probe request

Figure 9.19 Active scanning—directed probe request

Figure 9.20 Probe requests—multiple channels

Figure 9.21 Joining the BSS

Figure 9.22 Reassociation process

Figure 9.23 Action frame structure

Figure 9.24 ACK control frame

Figure 9.25 Immediate Block ACK

Figure 9.26 RTS/CTS duration values

Figure 9.27 RTS/CTS frame exchange

Figure 9.28 Protection mechanism—RTS/CTS

Figure 9.29 Protection mechanism—CTS-to-Self

Figure 9.30 Legacy power management

Figure 9.31 WMM-PS

Chapter 10

Figure 10.1 MIMO operation and multipath

Figure 10.2 2×3 and 3×3 MIMO

Figure 10.3 Multiple spatial streams

Figure 10.4 Maximal ratio combining

Figure 10.5 Transmit beamforming data

Figure 10.6 Single-user beamforming sounding process

Figure 10.7 Multiuser MIMO

Figure 10.8 Multiuser beamforming sounding process

Figure 10.9 Beamformed transmissions in a MU-MIMO environment

Figure 10.10 MU-MIMO block acknowledgments

Figure 10.11 20 MHz non-HT (802.11a/g) channel

Figure 10.12 20 MHz HT or VHT channel

Figure 10.13 40 MHz HT or VHT channel

Figure 10.14 Channel bonding

Figure 10.15 Channel bonding—5 GHz U-NII bands

Figure 10.16 Channel bonding—2.4 GHz ISM band

Figure 10.17 80 MHz VHT (802.11ac) channel

Figure 10.18 20, 40, 80, and 160 MHz channels

Figure 10.19 Guard interval

Figure 10.20 64-QAM constellation chart

Figure 10.21 256-QAM constellation chart

Figure 10.22 Example target

Figure 10.23 PPDU formats

Figure 10.24 802.11 unicast frame overhead

Figure 10.25 A-MSDU

Figure 10.26 A-MPDU

Figure 10.27 A-MSDU, ACKs, and retransmissions

Figure 10.28 A-MPDU, Block ACKs, and retransmissions

Chapter 11

Figure 11.1 PCMCIA adapter/PC card

Figure 11.2 802.11 USB radio

Figure 11.3 Mini PCI and Mini PCI Express radios

Figure 11.4 Bar code scanner

Figure 11.5 Embedded 802.11 radio

Figure 11.6 Integrated OS client utility for Windows 10

Figure 11.7 Wireless diagnostic tool for macOS 10.13

Figure 11.8 Integrated OS client utility for iOS 11.0

Figure 11.9 Enterprise-class client utility

Figure 11.10 Third-party client utility

Figure 11.11 Autonomous WLAN architecture

Figure 11.12 NMS diagnostic utilities

Figure 11.13 NMS client monitoring

Figure 11.14 Centralized WLAN architecture: WLAN controller

Figure 11.15 Centralized data forwarding

Figure 11.16 Distributed data forwarding

Figure 11.17 Distributed WLAN architecture

Figure 11.18 WLAN mesh network

Figure 11.19 Point-to-point WLAN bridging

Figure 11.20 Point-to-multipoint WLAN bridging

Figure 11.21 Common bridging challenge

Figure 11.22 WLAN array

Figure 11.23 Active 802.11 RFID tag

Figure 11.24 RTLS application

Figure 11.25 VoWiFi phone (Spectralink 84-Series VoWiFi phone)

Figure 11.26 Vocera communications badge

Figure 11.27 Elastic cloud architecture

Figure 11.28 Tamper-evident label

Figure 11.29 PuTTY freeware SSH2 client

Chapter 12

Figure 12.1 48-port Gigabit Ethernet access switch with PoE

Figure 12.2 10BaseT/100BaseTX endpoint PSE, Alternative A

Figure 12.3 1000BaseT endpoint PSE, Alternative A

Figure 12.4 10BaseT/100BaseTX endpoint PSE, Alternative B

Figure 12.5 1000BaseT endpoint PSE, Alternative B

Figure 12.6 10BaseT/100BaseTX midspan PSE, Alternative A

Figure 12.7 1000BaseT midspan PSE, Alternative A

Figure 12.8 10BaseT/100BaseTX midspan PSE, Alternative B

Figure 12.9 1000BaseT midspan PSE, Alternative B

Figure 12.10 PowerDsine power injector and PoE hubs

Figure 12.11 Three PSE solutions

Figure 12.12 Port-level PoE budgeting

Figure 12.13 Power budget monitoring

Figure 12.14 Netscout LinkSprinter network tester

Chapter 13

Figure 13.1 Signal-to-noise ratio

Figure 13.2 VoWiFI vs. high data rate coverage

Figure 13.3 Dynamic rate switching

Figure 13.4 Roaming

Figure 13.5 Roaming aggressiveness

Figure 13.6 Cell overlap

Figure 13.7 Primary and secondary coverage

Figure 13.8 Layer 3 roaming boundaries

Figure 13.9 Mobile IP

Figure 13.10 2.4 GHz non-overlapping channels

Figure 13.11 2.4 GHz channel reuse pattern

Figure 13.12 Improper channel reuse—adjacent channel interference

Figure 13.13 Three-dimensional channel reuse

Figure 13.14 5 GHz channels

Figure 13.15 Improper channel reuse—co-channel interference

Figure 13.16 Co-channel interference—APs

Figure 13.17 Co-channel interference—clients

Figure 13.18 5 GHz channel reuse pattern

Figure 13.19 Preventing CCI with 5 GHz channel reuse

Figure 13.20 DFS Radar Signal Generator

Figure 13.21 40 MHz channels

Figure 13.22 40 MHz channel reuse—4 channels

Figure 13.23 40 MHz channel reuse—12 channels

Figure 13.24 Adaptive RF cost calculation

Figure 13.25 Single-channel architecture

Figure 13.26 Zero handoff time

Figure 13.27 Density predictive modeling

Figure 13.28 Capacity-planning spreadsheet

Figure 13.29 One AP per room—5 GHz

Figure 13.30 Band steering to 5 GHz

Figure 13.31 Band steering for frequency balancing

Figure 13.32 Load balancing between APs

Figure 13.33 Frame transmission time

Figure 13.34 Basic rates—5 GHz

Figure 13.35 Basic rates - 2.4 GHz

Figure 13.36 SSID overhead calculator

Figure 13.37 2.4 GHz coverage vs. 5 GHz coverage

Figure 13.38 Disabling 2.4 GHz radio transmit capability

Figure 13.39 Dual 5 GHz coverage

Figure 13.40 Wall attenuation

Figure 13.41 Hallways are bad!

Figure 13.42 MIMO patch antenna

Figure 13.43 Warehouse WLAN—directional antennas

Figure 13.44 Warehouse WLAN—ceiling and wall mount coverage

Figure 13.45 Directional Junction Box antenna 

Figure 13.46 Stadium coverage - 3D view 

Chapter 14

Figure 14.1 Wi-Spy DBx 2.4 GHz and 5 GHz USB spectrum analyzer 

Figure 14.2 Ekahau Sidekick 

Figure 14.3 Spectrum analyzer view of a microwave oven 

Figure 14.4 Starting coverage cell

Figure 14.5 Second AP location

Figure 14.6 Signal-to-noise ratio

Figure 14.7 Commercial coverage analysis site survey software 

Figure 14.8 Measuring wall loss

Figure 14.9 Predictive model 

Figure 14.10 NetScout AirCheck G2 

Figure 14.11 TamoSoft throughput tester

Figure 14.12 WLAN mobile site survey tripod 

Figure 14.13 Typical floor plan

Figure 14.14 Topographic map

Chapter 15

Figure 15.1 OSI model

Figure 15.2 WLAN client database

Figure 15.3 Narrowband RF interference

Figure 15.4 Wideband RF interference

Figure 15.5 All-band RF interference

Figure 15.6 Fast BSS transition information element

Figure 15.7 Layer 2 ACK

Figure 15.8 Layer 2 retransmission

Figure 15.9 Layer 2 retransmission statistics

Figure 15.10 Signal-to-noise ratio

Figure 15.11 High and low signal-to-noise ratio

Figure 15.12 Adjacent cell interference

Figure 15.13 Hidden node—obstruction

Figure 15.14 Hidden node—large coverage cell

Figure 15.15 Hidden node—distributed antenna system

Figure 15.16 Hidden node and RTS/CTS

Figure 15.17 Mismatched AP and client power

Figure 15.18 Client-based co-channel interference

Figure 15.19 Transmit power control

Figure 15.20 Successful PSK authentication

Figure 15.21 Unsuccessful PSK authentication

Figure 15.22 802.1X/EAP

Figure 15.23 802.1X/EAP troubleshooting zones

Figure 15.24 The RADIUS server does not respond.

Figure 15.25 Points of failure—802.1X/EAP troubleshooting zone 1

Figure 15.26 802.1X/EAP backend diagnostic tool

Figure 15.27 Successful SSL/TLS tunnel creation

Figure 15.28 Unsuccessful SSL/TLS tunnel creation

Figure 15.29 Server certificate validation

Figure 15.30 RADIUS server rejects supplicant credentials

Figure 15.31 Machine authentication failure

Figure 15.32 4-Way Handshake

Figure 15.33 IPsec Phase 1—certificate failure

Figure 15.34 IPsec Phase 1—networking failure

Figure 15.35 IPsec Phase 2—Success

Figure 15.36 Seamless roaming

Figure 15.37 Multichannel monitoring and analysis

Figure 15.38 Roaming cache

Figure 15.39 GRE tunnel

Figure 15.40 Channel utilization

Figure 15.41 QBSS information element

Figure 15.42 School WLAN diagram

Figure 15.43 VLAN probe

Figure 15.44 DHCP probe

Figure 15.45 Backend DHCP failures

Figure 15.46 Misconfigured switch

Figure 15.47 WLAN discovery tool

Figure 15.48 Wi-Spy DBx 2.4 GHz and 5 GHz PC-based spectrum analyzer

Figure 15.49 EyePA analysis and remediation

Figure 15.50 TamoSoft throughput tester

Figure 15.51 PuTTy—freeware SSH and serial client

Chapter 16

Figure 16.1 Rogue access point

Figure 16.2 Bridged ad hoc WLAN

Figure 16.3 Client isolation

Figure 16.4 MetaGeek inSSIDer Office

Figure 16.5 WiFi Analyzer WLAN discovery tool

Figure 16.6 WEP-cracking utility

Figure 16.7 Offline dictionary attack

Figure 16.8 Wireless hijacking/man-in-the-middle attack

Figure 16.9 Wireless intrusion prevention system (WIPS)

Figure 16.10 WIPS monitoring

Figure 16.11 Wireless rogue containment

Chapter 17

Figure 17.1 Static WEP encryption key and initialization vector

Figure 17.2 Transmission key

Figure 17.3 WEP encryption process

Figure 17.4 Client configured with static passphrase

Figure 17.5 Proprietary PSK

Figure 17.6 802.1X comparison—standalone vs. controller-based access points

Figure 17.7 802.1X/EAP frame exchange

Figure 17.8 Tunneled authentication

Figure 17.9 802.1X/EAP and dynamic keys

Figure 17.10 4-Way Handshake

Figure 17.11 802.11 data frame

Figure 17.12 Wireless VLANs

Figure 17.13 RADIUS attributes for role assignment

Figure 17.14 VPN components

Figure 17.15 VPN established from a public hotspot

Figure 17.16 Site-to-site VPN

Figure 17.17 WLAN bridging and VPN security

Chapter 18

Figure 18.1 Personal mobile devices with Wi-Fi radios

Figure 18.2 Device restrictions

Figure 18.3 MDM enrollment—initial steps

Figure 18.4 MDM server—Enrollment captive web portal—

step 4

Figure 18.5 Certificate and MDM profile installation—

step 5

Figure 18.6 Mobile device released from the walled garden

Figure 18.7 MDM profile settings

Figure 18.8 MDM agent application

Figure 18.9 Device information

Figure 18.10 Over-the-air management

Figure 18.11 Mobile device applications

Figure 18.12 MDM distribution of the

CWNA Study Guide eBook

Figure 18.13 BYOD onboarding application

Figure 18.14 GRE tunneling guest traffic to a DMZ

Figure 18.15 Guest firewall policy

Figure 18.16 Application firewall policy

Figure 18.17 Captive web portal—DNS redirection

Figure 18.18 Captive web portal—guest login

Figure 18.19 Captive web portal—guest self-registration

Figure 18.20 Captive web portal—policy acceptance

Figure 18.21 Guest management and monitoring

Figure 18.22 Guest credential delivery methods

Figure 18.23 Kiosk mode

Figure 18.24 Employee sponsorship registration

Figure 18.25 Employee sponsorship confirmation email

Figure 18.26 OAuth 2.0 application

Figure 18.27 Social login

Figure 18.28 ANQP

Figure 18.29 GAS queries

Figure 18.30 Hotspot 2.0 WLAN

Figure 18.31 Online sign-up

Figure 18.32 Antivirus posture settings

Figure 18.33 Service provider–initiated login

Figure 18.34 Identity provider–initiated login

Chapter 19

Figure 19.1 802.11 traffic

Figure 19.2 802.11 data frame size

Figure 19.3 802.11n/ac 20 MHz channel—OFDM subcarriers

Figure 19.4 Subcarrier spacing

Figure 19.5 OFDM transmissions over time

Figure 19.6 OFDMA resource units

Figure 19.7 OFDMA transmissions over time

Figure 19.8 RU index and subcarrier range for 20 MHz channel

Figure 19.9 Trigger frame RU allocation

Figure 19.10 Downlink OFDMA

Figure 19.11 Uplink OFDMA

Figure 19.12 OBSS interference caused by a client

Figure 19.13 BSS color

Figure 19.14 Clear channel assessment—signal detect and energy detect thresholds

Figure 19.15 Spatial reuse operation – Adaptive CCA

Figure 19.16 Dual NAV timers

Figure 19.17 256-QAM and 1024-QAM

Figure 19.18 HE PPDU formats

Figure 19.19 HE-SIG-B

Figure 19.20 20 MHz-only 802.11ax client

Figure 19.21 Aggregate MPDU

Chapter 20

Figure 20.1 iBeacon proximity location identifier

Figure 20.2 D-Link wireless SOHO router

Figure 20.3 Retail analytics

Figure 20.4 Masimo Root with Radius-7, a patient-worn monitor

Figure 20.5 Example of a captive portal

Figure 20.6 FMC network design

Guide

Cover

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Table of Exercises

Exercise 3.1

Visual Demonstration of Absorption

Exercise 3.2

Visual Demonstration of Multipath and Phase

Exercise 4.1

Step-by-Step Use of the Rule of 10s and 3s

Exercise 4.2

Rule of 10s and 3s Example

Exercise 4.3

Link Budget and Fade Margin

Exercise 9.1

Viewing Beacon Frames

Exercise 9.2

Understanding Probe Requests and Probe Responses

Exercise 9.3

Using Open System Authentication

Exercise 9.4

Understanding Association

Exercise 9.5

Understanding Reassociation

Exercise 9.6

Viewing Action Frames

Exercise 9.7

Understanding Acknowledgment

Exercise 9.8

Using Data Frames

Exercise 14.1

Calculating Cable Loss

Exercise 17.1

Using Unencrypted and Encrypted Data Frames

Exercise 17.2

802.1X/EAP and the 4-Way Handshake Process

Foreword

Congratulations! Your purchase of this book means that you have decided to take the first step to truly formalize the expertise you have already developed working with 802.11 wireless local area networks (WLANs). You have chosen to dig deeper to understand the mechanics of the technology and to improve your troubleshooting skills. As the world transitions to an exclusively wireless access layer, it needs more well trained engineers to build and operate wireless networks.

When I passed my Certified Wireless Network Administrator (CWNA) exam over a decade ago in 2007, I could not have imagined that it would lead me to a senior strategy role at a major wireless equipment manufacturer, much less the honor of writing this foreword. At the time, I was leading a team of wireless engineers deploying WLANs for enterprise customers, and few of us had any formal training. The CWNA curriculum made an immediate difference in the quality of our networks, and I was hooked.

Over time, I achieved all the professional level CWNP certifications, and then went on to earn and become CWNE #112. These certifications enabled me to continue to not only grow professionally and deliver better performing systems to my customers, but also to begin to give back to the community by participating in the IEEE 802.11 Working Group and Wi-Fi Alliance. These standards development organizations (SDOs) are responsible for evolving the technology behind Wi-Fi. CWNP certification also led to publishing my own books on topics like high-density and outdoor Wi-Fi networks, as well as technical research to help explain the behavior of various aspects of the 802.11 protocols.

You will find that radio technology is an infinitely deep rabbit hole. There is always another layer to the onion. For example—just as atoms are made up of protons and electrons, which, in turn, are made up of quarks and leptons—learning about 802.11 data rates at the Physical layer will eventually lead you to symbols and subcarriers and then to modulation and coding techniques. Studying the Medium Access Control (MAC) layer will inevitably lead you to the statistical elegance that underpins the basic rules that govern how Wi-Fi devices manage airtime and determine who has the right to transmit. And on and on.

There is no limit to how far your interest can carry you. David Coleman and David Westcott—whom I have had the pleasure of knowing for many years now—are excellent guides. They have been educating wireless engineers for many years, and have structured this book to provide an in-depth overview of all the key areas that must be mastered to be truly effective as a wireless administrator.

Wi-Fi is here to stay, and the industry needs many more certified engineers. The Wi-Fi industry shipped over 3 billion chipsets in 2017, and the installed base is estimated to be over 10 billion worldwide. There are now more Wi-Fi devices than humans on Earth. A study issued earlier this year found that unlicensed spectrum contributes over $830 billion to the United States economy alone, to say nothing of other countries. Other studies have found that Wi-Fi networks are carrying between 50 and 80 percent of all IP traffic originating on mobile devices.

At the same time, the technology is continuously advancing. 802.11ax equipment will begin shipping in late 2018, bringing true multi-gigabit data rates, scheduled access, and new multi-user techniques, enabled by a major evolution in the PHY and MAC layers. Wi-Fi Protected Access 3 (WPA3) has just been announced, bringing a major revision to the encryption and authentication used to protect WLANs. So, we can never stop learning. After you have earned your CWNA, I encourage you to push further to become the best WLAN engineer you can possibly be, and in time to make your own contributions to the field.

  Chuck Lukaszewski

  CWNE #112, CWSP, CWAP, CWDP, CWNA

  Vice President, Wireless Strategy & Standards

  Aruba, a Hewlett Packard Enterprise Company

  June 2018

Introduction

If you have purchased this book or if you are thinking about purchasing this book, you probably have some interest in taking the CWNA® (Certified Wireless Network Administrator) certification exam or in learning more about what the CWNA certification exam encompasses. We would like to congratulate you on this first step, and we hope that our book can help you on your journey. Wireless networking is 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 not only to pass the CWNA certification test but also to be able to design, install, and support wireless networks. The CWNA certification is a required prerequisite for the training classes offered by many of the major WLAN vendors. 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 and an online learning environment 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 take your test. We recommend that you visit www.cwnp.com as you prepare to study for your test to determine what the current objectives and requirements are.

 Do not 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 exam. The practice questions will be different from the actual certification exam questions. If you learn and understand the topics and objectives, you will be better prepared for the test.

About CWNA® and CWNP®

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 probably also learning about an industry that you are unfamiliar with. Read on and we will tell you about CWNP.

CWNP is an abbreviation for Certified Wireless Network Professional. There is no CWNP test. The CWNP program develops courseware and certification exams for wireless LAN technologies in the computer networking industry. The CWNP certification program is a vendor-neutral program.

The objective of CWNP 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 certification 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 a car, you had to physically sit and practice in one. When you think back and reminisce, you probably do not tell someone you learned to drive a Ford; you probably say you learned to drive using a Ford.

The CWNP program offers the following nine wireless certifications:

CWS: Certified Wireless Specialist CWS is an entry-level WLAN certification exam (CWS-100) for those in sales, marketing, and entry-level positions related to Wi-Fi. CWS teaches the language of Wi-Fi and is an excellent introduction to enterprise Wi-Fi.

CWT: Certified Wireless Technician CWT is an entry-level WLAN certification exam (CWT-100) for teaching technicians to install and configure Wi-Fi at the basic level. CWT provides the skills needed to install and configure an AP to specifications and configure a client device to connect to and use the WLAN.

CWTS: Certified Wireless Technology Specialist CWTS is an entry-level WLAN certification exam (PW0-071) for sales professionals, project managers, and networkers who are new to enterprise Wi-Fi. Learn what Wi-Fi is before you learn how it works.

CWNA: Certified Wireless Network Administrator The CWNA certification is an administration-level Wi-Fi certification exam (CWNA-107) for networkers who are in the field and need to thoroughly understand RF behavior, site surveying, installation, and basic enterprise Wi-Fi security. CWNA is where you learn how RF and IP come together as a Wi-Fi network. The CWNA certification was the original certification of the CWNP program and is considered to be the foundation-level certification in the Wi-Fi industry. CWNA is the base certification for enterprise Wi-Fi within the CWNP family of certifications and a springboard toward earning CWSP, CWDP, CWAP, and CWNE certifications.

CWSP: Certified Wireless Security Professional The CWSP certification exam (CWSP-205) is a professional-level Wi-Fi certification for network engineers who seek to establish their expertise in enterprise Wi-Fi security. Contrary to popular belief, enterprise Wi-Fi can be secure, if the IT professionals installing and configuring it understand how to secure the wireless network. You must have a current CWNA credential to take the CWSP exam.

CWDP: Certified Wireless Design Professional