CWNA Certified Wireless Network Administrator Study Guide: Exam CWNA-108

By David A. Westcott and David D. Coleman

The #1 selling Wi-Fi networking reference guide in the world 

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 pass the exam. But passing the exam is just a first step. For over 16 years, the CWNA Study Guide has helped individuals jump-start their wireless networking careers. Wireless networking professionals across the globe use this book as their workplace reference guide for enterprise Wi-Fi technology. 

Owning this book provides you with a foundation of knowledge for important Wi-Fi networking topics, including: 

• Radio frequency (RF) fundamentals
• 802.11 MAC and medium access
• Wireless LAN topologies and architecture
• WLAN design, troubleshooting and validation
• Wi-Fi networking security 

The book authors have over 40 years of combined Wi-Fi networking expertise and provide real-world insights that you can leverage in your wireless networking career. Each of the book’s 20 chapters breaks down complex topics into easy to understand nuggets of useful information. Each chapter has review questions that help you gauge your progress along the way. Additionally, hands-on exercises allow you to practice applying CWNA concepts to real-world scenarios. 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 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 networks functioning and safe. The CWNA: Certified Wireless Network Administrator Study Guide gives you everything you need to pass the exam with flying colors. 

• Language: English
• Publisher: Wiley
• Release date: Feb 17, 2021
• ISBN: 9781119734536

Book preview

CWNA®

Certified Wireless Network Administrator

Study Guide

Exam CWNA-108

Sixth Edition

Logo: Wiley

David D. Coleman, CWNE #4

David A. Westcott, CWNE #7

Logo: Wiley

Copyright © 2021 by John Wiley & Sons, Inc., Indianapolis, Indiana

Published simultaneously in Canada and the United Kingdom

ISBN: 978-1-119-73450-5

ISBN: 978-1-119-73633-2 (ebk.)

ISBN: 978-1-119-73453-6 (ebk.)

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, [phone], fax [phone]. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, [phone], fax [phone], or online at www.wiley.com/go/permissions.

Limit of Liability/Disclaimer of Warranty: The publisher and the author make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation warranties of fitness for a particular purpose. No warranty may be created or extended by sales or promotional materials. The advice and strategies contained herein may not be suitable for every situation. This work is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional services. If professional assistance is required, the services of a competent professional person should be sought. Neither the publisher nor the author shall be liable for damages arising herefrom. The fact that an organization or Web site is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Web site may provide or recommendations it may make. Further, readers should be aware that Internet Web sites listed in this work may have changed or disappeared between when this work was written and when it is read.

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 [phone], outside the U.S. at [phone] or fax [phone].

Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some material included with standard print versions of this book may not be included in e-books or in print-on-demand. If this book refers to media such as a CD or DVD that is not included in the version you purchased, you may download this material at booksupport.wiley.com. For more information about Wiley products, visit www.wiley.com.

Library of Congress Control Number: 2020951883

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 17 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 in 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. Six 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 five 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 6th 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 children. 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 would especially like to thank his wife, Valla Ann, for bringing joy and laughter into his life every day.

David Coleman would also like to thank his friends and family at Extreme Networks (www.extremenetworks.com) and the former Aerohive Networks. There are many past and present Aerohive and Extreme employees he would like to thank, but there simply is not enough room. So thank you to all of his co-workers. It has been one wild ride the past 11 years!

David Westcott would like to thank his wife, Janie, for her love and support, and for being the cornerstone of his family. Her love and daily support of four generations of family does not go unnoticed or unappreciated.

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 sixth 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 content refinement specialist, Barath Kumar Rajasekaran; Elizabeth Welch, our copyeditor; and Louise Watson, our proofreader.

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 provided him. You can see much more of his work and talent at www.andrewcrocker.photography.

Thanks to Proxim and to Ken Ruppel ([e-mail]) 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/cwnasg6e.

Special thanks goes to Andras Szilagyi, for creating the EMANIM web application that is used with the exercises in Chapter 3, Radio Frequency Fundamentals. You can reach Andras at www.szialab.org.

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

Thanks to Marko Tisler, CWNE #126, for his content contribution about APIs. 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 and Wi-Fi 6E.

Most gracious appreciation to Rick Murphy, CWNE #10, for his content regarding OFDM. Rick offers some outstanding WLAN training resources at howwirelessworks.com.

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.intuitibits.com.

We have to give a big shout-out to Lee Badman, CWNE #200, for his parody blogs and memes that he has created about past editions of this book. (He writes great technical blogs as well.)

Some other WLAN rock stars that are mentioned in the copy of this book: Sam Clements, CWNE #101; Nigel Bowden, CWNE #135; Mike Albano, CWNE #150; Eddie Forero, CWNE #160; James Garringer, CWNE #179; Glen Cate, CWNE #181; Jerome Henry, CWNE #45; François Vergès, CWNE #180; Rowell Dionicio, CWNE #210; Manon Lessard, CWNE #275; Phil Morgan, CWNE #322; Mac Deryng, CWNE #357, and Matt Starling, CWNE #369.

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.divdyn.com)

Dennis Burrell, Product Innovation Technologist at Ventev (www.ventev.com)

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

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

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

Tina Hanzlik, Director, Marketing Communications and Cari Eissler, Senior Marketing Communications Manager at the Wi-Fi Alliance (www.wi-fi.org)

James Kahkoska, CTO of NetAlly (www.netally.com)

Brian Long, CWNE #159, VP, Global Professional Services and Education at Masimo (www.masimo.com)

Tauni Odia, Director of Product Marketing at Ekahau (www.ekahau.com)

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

Ryan Woodings, Founder of MetaGeek (www.metageek.com)

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

We would also like to thank at 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 Mark Hung, Vice President, Technology and Engineering at the Wi-Fi Alliance, for the thought-provoking foreword that he wrote for this book.

About the Authors

David D. Coleman is the Director of Product Marketing for Extreme Networks (www.extremenetworks.com). David is a public speaker and proficient technical author who specializes in Wi-Fi and cloud technologies, and he is a member of the Extreme Networks Technical Evangelism team. David travels the world for both customer and channel partner engagements, speaking events, and training sessions. He has instructed IT professionals from around the globe in Wi-Fi 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 Extreme, he specialized in corporate and government Wi-Fi training and consulting. In the past, he has provided Wi-Fi consulting for numerous private corporations, the U.S. military, and other federal and state government agencies. David is also the 2020 recipient of the Wi-Fi Lifetime Achievement Award (www.thewifiawards.com/2020-award-winners). When he is not traveling, he resides in both Atlanta, Georgia, and Lake Chapala, Mexico, with his wife, Valla Ann. David is CWNE #4, and he can be reached via email at [e-mail]. Please follow David on Twitter: @mistermultipath.

David A. Westcottis an independent consultant and technical trainer with more than 35 years of experience. He has been a certified trainer for more than 28 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 at Boston University's Corporate Education Center for more than 10 years. He is the author of Understanding ArubaOS: Version 8.x (Bowker, 2019) and Understanding ArubaOS: Version 6.x (Westcott Consulting, Inc., 2017), and he has co-authored multiple books, written numerous white papers, and developed many courses on wired and wireless networking technologies and networking security.

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

About the Technical Editor

Ben Wilson has been involved with wireless since its early commercialized beginnings, working for different vendors and technologies along the way. Having worked in various roles, he has installed more APs and done more integrations than he cares to remember over the last 20 years. Today Ben works as VP of Project Management at Fortinet, where he helps drive product strategy, direction, and development for wireless and other technologies. Please follow Ben on Twitter: @AirNetworkBen.

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 SAE and 4-Way Handshake Process

EXERCISE 17.3 802.1X/EAP and 4-Way Handshake Process

Foreword

Wi-Fi is one of the most widely adopted technologies around the world. Today, nearly every mobile device ships with Wi-Fi. According to the International Data Corporation, there is currently an installed base of over 13 billion Wi-Fi devices, and the number only continues to grow, with more than 4.5 billion Wi-Fi devices predicted to ship annually in 2024, according to ABI Research.

Wi-Fi ubiquity was not always guaranteed. When the first 802.11 protocol was released in 1997, there were no standards bodies to ensure that products from various vendors could work productively together. So, in 1999, when the original Wi-Fi standard was introduced with 802.11b, Wi-Fi Alliance was founded as a global organization to ensure multivendor interoperability for wireless networking products that brings a better and more consistent connectivity experience. Wi-Fi CERTIFIED was established to indicate products that passed interoperability requirements from Wi-Fi Alliance, and devices bearing the distinctive Wi-Fi logo have since become synonymous with high quality and reliability.

Wi-Fi CERTIFIED programs contributed greatly to the rapid rise of Wi-Fi, and today Wi-Fi CERTIFIED is an internationally recognized seal of approval with more than 50,000 certifications. Devices undergo rigorous testing, providing assurances that a wide range of Wi-Fi devices will work well together. The Wi-Fi CERTIFIED logo now appears on products worldwide, indicating adherence to interoperability, security, and ease of use standards.

Wi-Fi Alliance has strived to go beyond interoperability and has contributed to several areas that have enabled Wi-Fi to become one of the world's most familiar and commonly used technologies. Security, versatility, and ease of use have been key focus areas. Wi-Fi Alliance established Wi-Fi Protected Access as a standards-based, interoperable security framework to provide an unprecedented level of security on all Wi-Fi CERTIFIED devices and has continued to evolve security standards, recently introducing Wi-Fi CERTIFIED WPA3. In addition to ensuring Wi-Fi remains secure, Wi-Fi CERTIFIED has enabled the wireless industry to connect an expanding range of consumer electronics devices, from mobile phones and 4K Ultra HD televisions to home thermostats and doorbells, by helping develop programs that improve device performance across a variety of environments, while also lowering power consumption in some applications. Finally, Wi-Fi Alliance has made Wi-Fi technology accessible to the broader public, introducing programs such as Wi-Fi CERTIFIED Easy Connect, which makes configuring Wi-Fi devices as simple as scanning a product QR code.

Although Wi-Fi's past has been impressive, the possibilities for the technology only continue to grow. In early 2020, the U.S. Federal Communications Commission (FCC) made the historic decision to open up unlicensed spectrum in the 6 GHz band for Wi-Fi use. Shortly thereafter the UK Office of Communications (Ofcom) announced that it would free up a portion of spectrum in the 6 GHz band for indoor Wi-Fi use. Meanwhile, regulators around the world are discussing using the 6 GHz band in their countries for unlicensed spectrum as well. With the 6 GHz band, essential spectrum resources are available to increase Wi-Fi economic contributions by paving the way for faster, higher-capacity, and lower-latency Wi-Fi devices and networks.

To ensure interoperability and foster Wi-Fi's continued growth, the Wi-Fi Alliance has expanded Wi-Fi CERTIFIED 6 into 6 GHz—with Wi-Fi 6E features—so that users can quickly benefit from this additional capacity.

The future is bright, both for the technology and for the professionals who find their calling in this dynamic and challenging field. There is always something new to learn, new puzzles to solve. I hope this book whets your appetite for the possibilities ahead, and with your CWNA certification in hand, you can set off confidently on a career that is sure to be both personally and professionally rewarding.

Mark Hung

Vice President, Technology and Engineering

Wi-Fi Alliance

December 2020

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 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 exercises 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.

Warning 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 CWNP program offers eight certifications with a focus on Wi-Fi and 802.11 wireless technology. Recently, the CWNP program has also begun to offer a certification track about other wireless technologies with a focus on Internet of Things (IoT) connectivity.

The objective of CWNP is to certify people in 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 eight Wi-Fi 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.

An illustration of the Logo of CWS: Certified Wireless Specialist.

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.

An illustration of the Logo of CWT: Certified Wireless Technician.

CWNA: Certified Wireless Network Administrator The CWNA certification is an administration-level Wi-Fi certification exam (CWNA-108) 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.

An illustration of the Logo of CWNA: Certified Wireless Network Administrator.

CWSP: Certified Wireless Security Professional The CWSP certification exam (CWSP-206) 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.

An illustration of the Logo of CWSP: Certified Wireless Security Professional.

CWDP: Certified Wireless Design Professional The CWDP certification exam (CWDP-303) is a professional-level career certification for networkers who are already CWNA certified and have a thorough understanding of RF technologies and applications of 802.11 networks. The CWDP curriculum prepares WLAN professionals to properly design wireless LANs for different applications to perform optimally in different environments. You must have a current CWNA credential to take the CWDP exam.

An illustration of the Logo of CWDP: Certified Wireless Design Professional.

CWAP: Certified Wireless Analysis Professional The CWAP certification exam (CWAP-403) is a professional-level career certification for networkers who are already CWNA certified and have a thorough understanding of RF technologies and applications of 802.11 networks. The CWAP curriculum prepares WLAN professionals to analyze, troubleshoot, and optimize any wireless LAN. You must have a current CWNA credential to take the CWAP exam.

An illustration of the Logo of CWAP: Certified Wireless Analysis Professional.

CWNE: Certified Wireless Network Expert The CWNE certification is the highest-level certification in the CWNP program. By successfully completing the CWNE requirements, you will have demonstrated that you have the most advanced skills available in today's wireless LAN market. The CWNE certification requires CWNA, CWAP, CWDP, and CWAP certifications. Starting January 1, 2021, all CWNE applicants must have the CWISA certification and one external networking certification. To earn the CWNE certification, a rigorous application must also be submitted and approved by the CWNE Board of Advisors. A minimum of three years of verifiable, documented, full-time professional work experience related to enterprise Wi-Fi networks is required. CWNE applicants must also submit three endorsements from people familiar with the applicant's enterprise Wi-Fi work history.

An illustration of the Logo of CWNE: Certified Wireless Network Expert.

CWNT: Certified Wireless Network Trainer Certified Wireless Network Trainers are qualified instructors certified by the CWNP program to deliver CWNP training courses to IT professionals. CWNTs are technical and instructional experts in wireless technologies, products, and solutions. To ensure a superior learning experience, CWNP Education Partners are required to use CWNTs when delivering training using official CWNP courseware. More information about becoming a CWNT is available on the CWNP website.

An illustration of the Logo of CWNT: Certified Wireless Network Trainer.

Additionally, the CWNP program offers three certifications with a specific focus on wireless IoT technologies:

CWISA: Certified Wireless IoT Solutions Administrator The CWISA certification was developed because many WLAN professionals are called upon to administer non-802.11 wireless solutions in addition to Wi-Fi. This exam covers foundation-level knowledge of Bluetooth Low Energy (BLE), Zigbee, wireless location services, and cellular solutions. Exam candidates are also tested on a high-level awareness of APIs and network automation concepts.

An illustration of the Logo of CWISA: Certified Wireless IoT Solutions Administrator.

CWICP: Certified Wireless IoT Connectivity Professional The CWICP certification requires proficiency of IoT connectivity standards and operation in business and industrial networks. This knowledge can be applied to deploy and troubleshoot the most common wireless IoT protocols with an in-depth understanding of their operations. This certification has a heavy emphasis on IEEE 802.15.4 protocols.

An illustration of the Logo of CWICP: Certified Wireless IoT Connectivity Professional.

CWIIP: Certified Wireless IoT Integration Professional The CWIIP certification is an advanced-level certification that requires systems development using APIs, programming, and libraries. Python programming fundamental skills are necessary. An understanding of wireless IoT protocols such as MQTT, CoAP, DDS, and AMQP is also a requirement.

An illustration of the Logo of CWIIP: Certified Wireless IoT Integration Professional.

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.

Note 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. After you have agreed, you will be able to continue with the test. If you pass the test, you are then a CWNA.

The information for the exam is as follows:

Exam name: Wireless LAN Administrator

Exam number: CWNA-108

Cost: $225 (in U.S. dollars)

Duration: 90 minutes

Questions: 60

Passing score: 70 percent (80 percent for instructors)

Available languages: English

Availability: Register at Pearson VUE (www.vue.com/cwnp)

When you schedule the exam, you will receive instructions regarding appointment and cancellation procedures, ID requirements, and information about the testing center location. In addition, you will receive a registration and payment confirmation letter. Exams can be scheduled weeks in advance, or in some cases, even as late as the same day. Exam vouchers can also be purchased at the CWNP website.

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 CWNA exam, the CWSP exam, the CWDP exam, or the CWAP exam that is current at that time. If the information you provided to the testing center is correct, you will receive an email from CWNP recognizing your accomplishment and providing you with a CWNP certification number.

Note We highly encourage you to recheck the CWNP and Person VUE sites for up-to-date example policies and FAQs when you begin studying for the CWNA, when you register to take the exam, and again in the days leading up to your exam itself so that you are aware of any new or changed options or requirements for exam takers.

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 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 is not for you. It is written for people who want to acquire hands-on skills and in-depth knowledge of wireless networking. WLAN professionals worldwide purchase this book as a general reference guide for 802.11 technology. This book is considered to be the top vendor-neutral Wi-Fi reference guide for IT administrators.

How to Use This Book and the Online Resources

We have included several testing features in the book and online resources. These tools will help you retain vital exam content as well as prepare you to sit for the actual exam.

Before You Begin At the beginning of the book (right after this introduction) is an assessment test that 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 that 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.

Chapter Review Questions To test your knowledge as you progress through the book, there are review questions at the end of each chapter. As you finish each chapter, answer the review questions and then check your answers. You can go back and reread the section that deals with each question you answered incorrectly to ensure that you answer correctly the next time you are tested on the material.

Sybex Online Learning Environment

The Sybex Online Learning Environment for this book includes flashcards, a test engine, and a glossary. To start using these to study for the CWNA exam go to www.wiley.com/go/sybextestprep, register your book to receive your unique PIN, and then once you have the PIN, return to www.wiley.com/go/sybextestprep and register a new account or add this book to an existing account.

Test Engine The test engine includes two bonus practice exams. You can use them as if you were taking the exam to rate your progress toward being ready. The test engine also includes all of the end-of-chapter review questions and the pre-book assessment questions. You can study by chapter or you can have the test engine mix and match questions from multiple chapters or the bonus exams. The test engine also comes with a practice mode (where you can see hints) as well as an exam mode (like the real test).

Flashcards These are short questions and answers like the ones you probably used in school, but these flashcards are online.

Glossary This glossary is an electronic list of key terms and their definitions.

Additional Online Resources

Exercises Several chapters in this book have labs that use resources you can download from the book's website (www.wiley.com/go/cwnasg6e). These exercises provide you with a broader learning experience by supplying hands-on experience and step-by-step problem solving. Some of the included hands-on materials you can download include PCAP frame captures to reinforce what you learn about 802.11 wireless frames in Chapters 9, 802.11 MAC, and 17, 802.11 Network Security Architecture."

White Papers Several chapters in this book reference wireless networking white papers that are available from the referenced websites. These white papers serve as additional reference material for preparing for the CWNA exam.

Getting Help Online

We hope your experience with the Sybex Online Learning Environment and the additional online resources is smooth. But if you have any issues with the online materials or the book itself, please start by reporting your issue to our 24/7 technical support team at support.wiley.com. They have live online chat as well as email options.

CWNA Exam (CWNA-108) Objectives

The CWNA exam measures your understanding of the fundamentals of RF behavior, your ability 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.

The skills and knowledge measured by this exam were 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 – 15%

1.1 Define and explain the basic characteristics of RF and RF behavior

Wavelength, frequency, amplitude, phase, sine waves

RF propagation and coverage

Reflection, refraction, diffraction, and scattering

Multipath and RF interference

Gain and loss

Amplification

Attenuation

Absorption

Voltage standing wave ratio (VSWR)

Return Loss

Free space path loss (FSPL)

1.2 Apply the basic concepts of RF mathematics and measurement

Watt and milliwatt

Decibel (dB)

dBm and dBi

Noise floor

SNR

RSSI

dBm to mW conversion rules of 10 and 3

Equivalent isotropically radiated power (EIRP)

1.3 Identify RF signal characteristics as they relate to antennas

RF and physical line of sight and Fresnel zone clearance

Beamwidths

Passive gain

Polarization

Antenna diversity types

Radio chains

Spatial multiplexing (SM)

Transmit beamforming (TxBF)

Maximal ratio combining (MRC)

MIMO

1.4 Explain and apply the functionality of RF antennas and antenna systems and accessories available

Omni-directional antennas

Semi-directional antennas

Highly directional antennas

Antenna orientation

Reading Azimuth and Elevation charts for different antenna types

RF cables and connectors

Lightning arrestors and grounding rods/wires

WLAN Regulations and Standards – 20%

2.1 Explain the roles of WLAN and networking industry organizations

IEEE

Wi-Fi Alliance

IETF

Regulatory domains and agencies

2.2 Explain and apply the various Physical Layer (PHY) solutions of the IEEE 802.11-2016 standard as amended, including supported channel widths, spatial streams, and data rates

DSSS – 802.11

HR-DSSS – 802.11b

OFDM – 802.11a

ERP – 802.11g

Wi-Fi 4 – HT – 802.11n

Wi-Fi 5 – VHT – 802.11ac

Wi-Fi 6 – HE – 802.11ax

2.3 Understand spread spectrum technologies, Modulation, and Coding Schemes (MCS)

DSSS

OFDM

OFDMA and resource units

BPSK

QPSK

QAM (16, 24, 256, 1024)

2.4 Identify and apply 802.11 WLAN functional concepts

Primary channels

Adjacent overlapping and non-overlapping channels

Throughput vs. data rate

Bandwidth

Guard interval

2.5 Describe the OSI model layers affected by the 802.11-2016 standard and amendments

2.6 Identify and comply with regulatory domain requirements and constraints (specifically in 2.4 GHz and 5 GHz)

Frequency bands used by the 802.11 PHYs

Available channels

Regulatory power constraints

Dynamic frequency selection (DFS)

Transmit power control (TPC)

2.7 Explain basic use case scenarios for 802.11 wireless networks

Wireless LAN (WLAN) – BSS and ESS

Wireless bridging

Wireless ad hoc (IBSS)

Wireless mesh

WLAN Protocols and Devices – 20%

3.1 Describe the components that make up an 802.11 wireless service set

Stations (STAs)

Basic service set (BSS) (infrastructure mode)

SSID

BSSID

Extended service set (ESS)

IBSS (Ad hoc)

Distribution system (DS)

Distribution system media (DSM)

3.2 Define terminology related to the 802.11 MAC and PHY

MSDU, MPDU, PSDU, and PPDU

A-MSDU and A-MPDU

PHY preamble and header

3.3 Identify and explain the MAC frame format

MAC frame format

MAC frame addressing

3.4 Identify and explain the purpose of the three main 802.11 frame types

Management

Control

Data

3.5 Explain the process used to locate and connect to a WLAN

Scanning (active and passive)

Authentication

Association

Open System and Shard Key Authentication

Connecting to 802.1X/EAP and Pre-Shared Key authentication networks

BSS selection

Connecting to hidden SSIDs

3.6 Explain 802.11 channel access methods

DCF

EDCA

RTS/CTS

CTS-to-Self

NAV

Interframe spaces (SIFS, DIFS, EIFS,AIFS)

Physical carrier sense and virtual carrier sense

Hidden node

3.7 Explain 802.11 MAC operations

Roaming

Power save modes and frame buffering

Protection mechanisms

3.8 Describe features of, select, and install WLAN devices, control, and management systems

Access Points (APs)

WLAN controllers

Wireless network management systems

Wireless bridge and mesh APs

Client devices

WLAN Network Architecture and Design Concepts – 15%

4.1 Describe and implement Power over Ethernet (PoE) 802.3af, 802.3at, 802.3bt

Power Source Equipment

Powered Device

Midspan and endpoint PSEs

Power classes to include power differences between PSE and PD

Power budgets and powered port density

4.2 Define and describe differences, advantages, and constraints of the different wireless LAN architectures

Centralized data forwarding

Distributed data forwarding

Control, Management, and Data planes

Scalability and availability solutions

Tunneling, QoS, and VLANs

4.3 Describe design considerations for common deployment scenarios in wireless, such as coverage requirements, roaming considerations, throughput, capacity, and security

Design considerations for data

Design considerations for voice

Design considerations for video

Design considerations for location services, including Real-Time Location Services (RTLS)

Design considerations for highly mobile devices (e.g., tablets and smartphones)

Capacity planning for high- and very high-density environments

Design considerations for guest access/BYOD

Design considerations for supporting legacy 802.11 devices

4.4 Demonstrate awareness of common proprietary features in wireless networks

Airtime Fairness

Band Steering

Dynamic power and channel management features

4.5 Determine and configure required network services supporting the wireless network

DHCP for client addressing, AP addressing, and/or controller discovery

Time synchronization protocols (e.g., NTP, SNTP)

VLANs for segmentation

Authentication services (RADIUS, LDAP)

Access Control Lists for segmentation

Wired network capacity requirements

WLAN Network Security – 10%

5.1 Identify weak security options that should not be used in enterprise WLANs

WEP

Shared Key Authentication

SSID hiding as a security mechanism

MAC filtering

Use of deprecated security methods (e.g., WPA and/or WPA2 with TKIP)

Wi-Fi Protected Setup

5.2 Identify and configure effective security mechanisms for enterprise WLANs

Application of AES with CCMP for encryption and integrity

WPA2-Personal, including limitations and best practices for pre-shared (PSK) use

WPA2-Enterprise configuring wireless networks to use 802.1X, including connecting to RADIUS servers and appropriate EAP methods

5.3 Understand basic concepts of WPA3 and Opportunistic Wireless Encryption (OWE) and enhancements compared to WPA2

Understand basic security enhancements in WPA3 vs. WPA2

Understand basic security enhancements of encryption and integrity in WPA3 (e.g., CCMP, GCMP, AES)

Simultaneous Authentication of Equals (SAE) in WPA3 as an enhancement for legacy pre-shared key technology

Understand the purpose of Opportunistic Wireless Encryption (OWE) for public and guest networks

5.4 Describe common security options and tools used in wireless networks

Access control solutions (e.g., captive portals, NAC, BYOD)

Protected management frames

Fast Secure Roaming methods

Wireless Intrusion Prevention System (WIPS) and/or rogue AP detection

Protocol and spectrum analyzers

Best practices in secure management protocols (e.g., encrypted management HTTPS, SNMPv3, SSH2, VPN, and password management)

RF Validation – 10%

6.1 Verify and document that design requirements are met, including coverage, throughput, roaming, and connectivity with a post-implementation validation survey

6.2 Locate and identify sources of RF interference

Identify RF disruption from 802.11 wireless devices, including contention vs. interference and causes/sources of both, including co-channel contention (CCC), overlapping channels, and 802.11 wireless device proximity

Identify sources of RF interference from non-802.11 wireless devices based on the investigation of airtime and frequency utilization

Understand interference mitigation options, including removal of interference source or change of wireless channel usage

6.3 Perform application testing to validate WLAN performance

Network testing and service availability

VoIP testing

Real-time application testing

Throughput testing

6.4 Understand and use the basic features of validation tools

Use of throughput testers for validation tasks

Use of wireless validation software (specifically survey software and wireless scanners)

Use of protocol analyzers for validation tasks

Use of spectrum analyzers for validation tasks

WLAN Troubleshooting – 10%

7.1 Describe and apply common troubleshooting tools used in WLANs

Use of protocol analyzers for troubleshooting tasks

Use of spectrum analyzers for identifying sources of interference

Use of management, monitoring, and logging systems for troubleshooting tasks

Use of wireless LAN scanners for troubleshooting tasks

7.2 Identify and troubleshoot common wireless issues

Identify causes of insufficient throughput in the wireless distribution systems, including LAN port speed/duplex misconfigurations, insufficient PoE budget, and insufficient Internet or WAN bandwidth

Identify and solve RF interference using spectrum analyzers

CWNA Exam Terminology

The CWNP program uses specific terminology when phrasing the questions on any of the CWNP exams. The terminology used most often mirrors the same language that is used by the Wi-Fi Alliance and in the IEEE. Although the CWNA exam objectives reference the IEEE 802.11-2016 standard, the most current IEEE version of the 802.11 standard is the IEEE 802.11-2020 document, which includes all the amendments that have been ratified prior to the document's publication. Standards bodies such as the IEEE often create several amendments to a standard before rolling up the ratified amendments (finalized or approved versions) into a new standard.

Tip To properly prepare for the CWNA exam, any test candidate should become 100 percent familiar with the terminology used by the CWNP program. This book defines and covers all terminology, including acronyms, terms, and definitions.

CWNP Authorized Materials Use Policy

CWNP does not condone the use of unauthorized training materials, also known as brain dumps. Individuals who utilize such materials to pass CWNP exams will have their certifications revoked. In an effort to more clearly communicate CWNP's policy on the use of unauthorized study materials, CWNP directs all certification candidates to the CWNP Candidate Conduct Policy, which is available on the CWNP website. Please review this policy before beginning the study process for any CWNP exam. Candidates will be required to state that they understand and have abided by this policy at the time of exam delivery.

Tips for Taking the CWNA Exam

Here are some general tips for taking your exam successfully:

Bring two forms of ID with you. One must be a photo ID, such as a driver's license. The other can be a major credit card or a passport. Both forms must include a signature.

Arrive early at the exam center so that you can relax and review your study materials, particularly tables and lists of exam-related information.

Read the questions carefully.

Do not be tempted to jump to an early conclusion. Make sure you know exactly what the question is asking.

There will be questions with multiple correct responses.

When there is more than one correct 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 correct answers you must choose.

When answering multiple-choice questions you are not sure about, use a process of elimination to get rid of the obviously incorrect answers first. Doing so will improve your odds if you need to make an educated guess.

Do not spend too much time on one question.

This is a form-based test; however, you cannot move backward through the exam. You must answer the current question before you can move to the next question, and after you have moved to the next question, you cannot go back and change your answer on a previous question.

Keep track of your time.

Because this is a 90-minute test consisting of 60 questions, you have an average of 90 seconds to answer each question. You can spend as much or as little time as you want to 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, do not panic. You will simply need to answer the remaining questions at a faster pace. If on average you can answer each of the remaining 30 questions 4 seconds faster, you will recover 2 minutes. Again, do not panic; just pace yourself.

For the latest pricing on the exams and updates to the registration procedures, visit CWNP's website at www.cwnp.com.

Assessment Test

At which layers of the OSI model does 802.11 technology operate? (Choose all that apply.)

Data-Link

Network

Physical

Presentation

Transport

Which Wi-Fi Alliance certification defines the mechanism for conserving battery life that is critical for handheld devices such as bar code scanners and VoWiFi phones?

WPA2-Enterprise

WPA2-Personal

WMM-PS

WMM-SA

Voice Enterprise

Which of these frequencies has the longest wavelength?

750 KHz

2.4 GHz

252 GHz

2.4 MHz

Which of these terms can best be used to compare the relationship between two radio waves that share the same frequency?

Multipath

Multiplexing

Phase

Spread spectrum

A wireless bridge transmits at 10 mW. The cable to the antenna produces a loss of 3 dB, and the antenna produces a gain of 20 dBi. What is the EIRP?

25 mW

27 mW

4 mW

1,300 mW

500 mW

dBi is an expression of what type of measurement?

Access point gain

Received power

Transmitted power

Antenna gain

Effective output

What are some possible effects of voltage standing wave ratio (VSWR)? (Choose all that apply.)

Increased amplitude

Decreased amplitude

Transmitter failure

Erratic amplitude

Out-of-phase signals

When installing a higher-gain omnidirectional antenna, which of the following occurs? (Choose two.)

The horizontal coverage increases.

The horizontal coverage decreases.

The vertical coverage increases.

The vertical coverage decreases.

802.11ac VHT radios are backward compatible with which IEEE 802.11 radios? (Choose two)

802.11 legacy (FHSS) radios

802.11g (ERP) radios

802.11 legacy (DSSS) radios

802.11b (HR-DSSS) radios

802.11a (OFDM) radios

2.4 GHz 802.11n (HT) radios

5 GHz 802.11n (HT) radios

Which IEEE 802.11 amendment defines multi-user operations in three frequency bands?

IEEE 802.11n

IEEE 802.11g

IEEE 802.11ac

IEEE 802.11ax

IEEE 802.11w

Which of the following measures the difference between the power of the primary RF signal and the sum of the power of the RF interference and the background noise?

Noise ratio

SNR

SINR

BER

DFS

What signal characteristics are common in spread spectrum and OFDM-based signaling methods? (Choose two.)

Narrow bandwidth

Low power

High power

Wide bandwidth

A service set identifier is often synonymous with which of the following?

Duration/ID

ESSID

BSSID

PMKID

Which ESS design scenario is required by the IEEE 802.11-2020 standard?

Two or more access points with overlapping coverage cells

Two or more access points with overlapping disjointed coverage cells

One access point with a single BSA

Two basic service sets interconnected by a distribution system medium (DSM)

None of the above

Which CSMA/CA conditions must be met before an 802.11 radio can transmit? (Choose all that apply.)

The NAV timer must be equal to zero.

The random backoff timer must have expired.

The CCA must be idle.

The proper interframe space must have occurred.

The access point must be in PCF mode.

Beacon management frames contain which of the following information? (Choose all that apply.)

Channel information

Destination IP address

Basic data rate

Traffic indication map (TIM)

Vendor proprietary information

Time stamp

Rebekah McAdams was hired to perform a wireless packet analysis of your network. While performing the analysis, she noticed that many of the data frames were preceded by an RTS frame followed by a CTS frame. What could cause this to occur? (Choose all that apply.)

AP automatically enabled RTS/CTS mechanisms as a response to co-channel interference.

An AP was manually configured with a low RTS/CTS threshold.

A nearby cell phone is causing some of the nodes to enable a protection mechanism.

Legacy 802.11b clients are connected to an 802.11g/n AP.

What is another name for an 802.11 data frame that is also known as a PSDU?

PPDU

MSDU

MPDU

BPDU

Which WLAN device uses dynamic and proprietary layer 2 routing protocols?

WLAN switch

WLAN controller

WLAN router

WLAN mesh access point

What term best describes the bulk of the data generated on the Internet being created by sensors, monitors, and machines?

Machine-to-machine (M2M)

Cloud-enabled networking (CEN)

Cloud-based networking (CBN)

Software as a service (SaaS)

Internet of Things (IoT)

Which technology subdivides a channel, allowing parallel transmissions of smaller frames to multiple users to occur simultaneously?

OFDMA

OFDM

MU-MIMO

DSSS

HR-DSSS

What term best describes how Wi-Fi can be used to identify customer behavior and shopping trends?

Radio analytics

Customer analytics

Retail analytics

Location analytics

The hidden node problem occurs when one client station's transmissions are not heard by some of the other client stations in the coverage area of a basic service set (BSS). What are some of the consequences of the hidden node problem? (Choose all that apply.)

Retransmissions

Intersymbol interference (ISI)

Collisions

Increased throughput

Decreased throughput

What are some potential causes of layer 2 retransmissions? (Choose all that apply.)

RF interference

Low signal-to-noise ratio (SNR)

Dual-frequency transmissions

High signal-to-noise ratio (SNR)

Co-channel interference

Which of these solutions would be considered strong WLAN security?

SSID cloaking

MAC filtering

WEP

Shared Key authentication

CCMP/AES

TKIP

Which security standard defines port-based access control?

IEEE 802.11x

IEEE 802.3bt

IEEE 802.11i

IEEE 802.1X

IEEE 802.11s

What is the best tool for detecting an RF jamming denial-of-service attack?

Time-domain analysis software

Protocol analyzer

Spectrum analyzer

Predictive modeling software

Oscilloscope

Which of these attacks can be detected by a wireless intrusion prevention system (WIPS)? (Choose all that apply.)

Deauthentication spoofing

MAC spoofing

Rogue ad hoc network

Association flood

Rogue AP

You have been hired by the US-based XYZ Company to conduct a wireless site survey. Which government agencies need to be informed before a tower that exceeds 200 feet above ground level is installed? (Choose all that apply.)

RF regulatory authority

Local municipality

Fire department

Tax authority

Aviation authority

You have been hired by the ABC Corporation to conduct an indoor site survey. What information will be in the final site survey report? (Choose two.)

Security analysis

Coverage analysis

Spectrum analysis

Routing analysis

Switching analysis

Name a potential source of RF interference in the 5 GHz U-NII band.

Cordless phones

AM radio

FM radio

Microwave ovens

Bluetooth

When Wi-Fi 6E clients enter the marketplace, what is the most anticipated method of AP discovery?

Active scanning of the 6 GHz channels using probe request frames

Passive scanning of the 6 GHz channels using beacon frames

Out-of-band discovery using reduced neighbor reports (RNRs)

In-band discovery using reduced neighbor reports (RNRs)

In-band discovery using Fast Initial Link Setup (FILS) discovery announcement frames

What is the number one cause of layer 2 retransmissions?

Low SNR

Hidden node

Adjacent cell interference

RF interference

What must a powered device (PD) do to be considered PoE compliant (IEEE 802.3-2015, Clause 33)? (Choose all that apply.)

Be able to accept power in either of two ways (through the data lines or unused pairs).

Reply with a classification signature.

Reply with a 35-ohm detection signature.

Reply with a 25-ohm detection signature.

Receive 30 watts of power from the power sourcing equipment.

Wi-Fi 4 radios using 802.11n (HT) technology can operate on which frequency bands? (Choose all that apply.)

902–928 MHz

2.4–2.4835 GHz

5.15–5.25 GHz

5.47–5.725 GHz

5.925–6.425 GHz

What are some of the methods used to reduce MAC layer overhead, as defined by the 802.11n-2009 amendment? (Choose all that apply.)

A-MSDU

A-MPDU

MCS

PPDU

MSDU

Praveen has been asked make recommendations about how provide Wi-Fi access for corporate employees and devices in an environment with a high density of users. Which of these WLAN design strategies are considered best practices? (Choose all that apply.)

For the mission-critical client devices that support both the 2.4 GHz and 5 GHz bands, create an SSID only for 5 GHz.

For the mission-critical client devices that support both the 2.4 GHz and 5 GHz bands, create an SSID for both bands.

Disable 60 percent or more of the 2.4 GHz radios on the APs.

Disable 60 percent or more of the 5 GHz radios on the APs.

Do not disable any of the AP radios.

Roy has been hired to troubleshoot an enterprise Wi-Fi 6 network. The customer has recently deployed dual-frequency 4×4:4 APs that also include a third-sensor radio for WIPS monitoring. Most of the APs are operating with full functionality; however, the APs in one building seem to only be operating as 2×2:2 radios and the sensor radio has stopped working. What is the most likely root cause of this problem?

The problem APs are connected to switch ports that are only capable of 1 Gb uplinks.

The problem APs are connected to switch ports that are only 802.3af (15.4 watts) capable.

The problem APs are connected to access switch ports and not 802.1Q trunk ports.

The problem APs are connected to 802.1Q trunk switch ports and access trunk ports.

The problem APs are connected to half-duplex switch ports.

What can be delivered over the air to WLAN mobile devices, such as tablets and smartphones, when a mobile device management (MDM) solution is deployed?

Configuration settings

Applications

Certificates

Web clips

All of the above

WLAN vendors have begun to offer the capability for guest users to log in to a guest WLAN with preexisting social media credentials, such as Facebook or Twitter usernames and passwords. Which authorization framework can be used for social media logins to WLAN guest networks?

Kerberos

RADIUS

802.1X/EAP

OAuth

TACACS

Answers to the Assessment Test

A and C. The IEEE 802.11-2020 standard defines communication mechanisms at only the Physical layer and MAC sublayer of the Data-Link layer of the OSI model. For more information, see Chapter 1.

C. WMM-PS helps conserve battery power for devices using Wi-Fi radios by managing the time the client devices spend in sleep mode. Conserving battery life is critical for handheld devices, such as bar code scanners and VoWiFi phones. To take advantage of power-saving capabilities, both the device and the access point must support WMM-Power Save. For more information, see Chapter 8.

A. A 750 KHz signal has an approximate wavelength of 1,312 feet, or 400 meters. A 252 GHz signal has an approximate wavelength of less than 0.05 inches, or 1.2 millimeters. Remember, the higher the frequency of a signal, the smaller the wavelength property of an electromagnetic signal. For more information, see Chapter 3.

C. Phase involves the positioning of the amplitude crests and troughs of two waveforms. For more information, see Chapter 3.

E. The 10 mW of power is decreased by 3 dB, or divided by 2, giving 5 mW. This is then increased by 20 dBi, or multiplied by 10 twice, giving 500 mW. For more information, see Chapter 4.

D. Theoretically, an isotropic radiator can radiate an equal signal in all directions. An antenna cannot do this because of construction limitations. However, antennas are often referred to as isotropic radiators because they radiate RF energy. The gain, or increase, of power from an antenna when compared to what an isotropic radiator would generate is known as decibels isotropic (dBi). Another way of phrasing this is decibel gain referenced to an isotropic radiator, or change in power relative to an antenna. dBi is a measurement of antenna gain. For more information, see Chapter 4.

B, C, and D. Reflected voltage caused by an impedance mismatch may cause a degradation of amplitude, erratic signal strength, or even the worst-case scenario of transmitter burnout. See Chapter 5 for more information.

A and D. When the gain of an omnidirectional antenna is increased, the vertical coverage area decreases while the horizontal coverage area is increased. See Chapter 5 for more information.

E and G. 802.11ac (VHT) radios transmit in the 5 GHz U-NII bands and are not compatible with 2.4 GHz radios, such as 802.11 legacy (FHSS) radios, 802.11 legacy (DSSS) radios, 802.11b (HR-DSSS) radios, 802.11g (ERP) radios, or 802.11n radios, which transmit in the 2.4 GHz ISM frequency band. 802.11ac (VHT) radios are backward compatible with 5 GHz 802.11n (HT) radios and 802.11a (OFDM) radios. For more information, see Chapter 6.

D. The 802.11ax amendment defines the use of two multi-user technologies: MU-MIMO and OFDMA. These multi-user technologies can be used in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. For more information, see Chapters 6 and 19.

C. Signal-to-interference-plus-noise (SINR) relates the primary RF signal to both interference and noise. While the noise level tends not to fluctuate much, interference from other devices is likely to be more common and frequent. For more information, see Chapter 4.

B and D. Both spread spectrum and OFDM signals utilize bandwidth that is wider than what is required to carry the data and has low transmission power requirements. See Chapter 6 for more information.

B. The logical network name of a wireless LAN is often called an ESSID (extended service set identifier) and is essentially synonymous with SSID (service set identifier), which is another term for a logical network name in the most common deployments of a WLAN. For more information, see Chapter 7.

E. The scenarios described in options A, B, C, and D are all examples of how an extended service set may be deployed. The IEEE 802.11-2020 standard defines an extended service set (ESS) as a set of one or more interconnected basic service sets. However, the IEEE 802.11-2020 standard does not mandate any of the examples given in the options. For more information, see Chapters 2 and 7.

A, B, C, and D. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is a wireless medium access method that utilizes multiple checks and balances to try to minimize collisions. These checks and balances can also be thought of as several lines of defense. The various lines of defense are put in place to hopefully ensure that only one radio is transmitting while all other radios are listening. The four lines of defense include the network allocation vector, the random backoff timer, the clear channel assessment, and interframe spacing. For more information, see Chapter 8.

A, C, D, E, and F. From the list of choices, the only information not contained in the beacon management frame is the destination IP address. The body of all 802.11 management frames contains only layer 2 information; therefore, IP information is not included in the frame. Other information that is included in a beacon includes security and QoS parameters. For more information, see Chapter 9.

B and D. AP radios can be manually configured to use RTS/CTS for all transmissions. This is usually done to diagnose hidden node problems or to prevent hidden node problems when installing point-to-multipoint wireless bridge links. RTS/CTS is automatically enabled as a protection mechanism when legacy clients co-exist in the same wireless environment as devices with newer 802.11 technologies. This allows for backward compatibility. For more information, see Chapter 9.

C. The technical name for an 802.11 data frame is MAC protocol data unit