CWNA Certified Wireless Network Administrator Study Guide

Exam CWNA-108

David D. Coleman, David A. Westcott

• Éditeur: Sybex
• Année: 2021
• ISBN:
  9781119734536
• Édition: 6
• Sujet: Ciencia de la computación
• Sous-sujet: Guías de certificación en ciencias computacionales

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 youpass the exam. But passing the exam is just a first step. For over16 years, the CWNA Study Guide has helpedindividualsjump-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 breaksdown complex topics into easy to understand nuggets of useful information. Each chapter has review questionsthathelp 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 theSybexonline 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 wirelessnetworksfunctioning and safe. The CWNA: Certified Wireless Network Administrator Study Guide gives you everything you need to pass the exam with flying colors.

Chapter 1
Overview of Wireless Standards, Organizations, and Fundamentals

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IN THIS CHAPTER, YOU WILL LEARN ABOUT THE FOLLOWING:

• History of wireless local area networks
• Standards organizations
  • Federal Communications Commission
  • International Telecommunication Union Radiocommunication Sector
  • Institute of Electrical and Electronics Engineers
  • Internet Engineering Task Force
  • Wi-Fi Alliance
  • International Organization for Standardization
• Core, distribution, and access
• Communications fundamentals
  • Communication terminology
  • Carrier signals
  • Keying methods

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Wireless local area network (WLAN) technology has a long history that dates back to the 1970s, with roots as far back as the 19th century. This chapter will start with a brief history of WLAN technology. Learning a new technology can seem like a daunting task. There are so many new acronyms, initialisms, abbreviations, terms, and ideas to become familiar with. One of the keys to learning any subject is to learn the basics. Whether you are learning to drive a car, fly an airplane, or install a wireless computer network, there are basic rules, principles, and concepts that, once learned, provide the building blocks for the rest of your education.

The Institute of Electrical and Electronics Engineers (IEEE) 802.11 technology, more commonly referred to as Wi-Fi, is a standard technology for providing local area network (LAN) communications using radio frequencies (RFs). The IEEE designates the 802.11-2020 standard as a guideline to provide operational parameters for WLANs. Numerous standards organizations and regulatory bodies help govern and direct wireless technologies and the related industry. Having some knowledge of these various organizations can provide you with insight as to how IEEE 802.11 functions and sometimes even how and why the standards have evolved the way they have.

As you become more knowledgeable about wireless networking, you may want or need to read some of the standards documents that are created by the different organizations. Along with the information about the standards bodies, this chapter includes a brief overview of their documents.

In addition to reviewing the various standards organizations that guide and regulate Wi-Fi, this chapter discusses where WLAN technology fits in with basic networking design fundamentals. Finally, this chapter reviews some fundamentals of communications and data keying that are not part of the CWNA exam but may help you better understand wireless communications.

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How Does an Acronym Differ from an Initialism?

In the world of science and technology, it is common to abbreviate technical names or phrases to make them simpler to use when speaking or writing about the technology. Acronyms and initialisms are abbreviations composed of the first letter of a series of words, such as RADIUS (Remote Authentication Dial-In User Service) or TCP (Transmission Control Protocol). If the abbreviation is pronounced like a word, such as RADIUS, then the abbreviation is an acronym. If the abbreviation is pronounced by saying the individual letters, such as TCP, then the abbreviation is an initialism.

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History of Wireless Local Area Networks

In the 19th century, numerous inventors and scientists, including Michael Faraday, James Clerk Maxwell, Heinrich Rudolf Hertz, Nikola Tesla, David Edward Hughes, Thomas Edison, and Guglielmo Marconi, began to experiment with wireless communications. These innovators discovered and created many theories about the concepts of electrical magnetic radio frequency (RF).

Wireless networking technology was first used by the U.S. military during World War II to transmit data over an RF medium using classified encryption technology to send battle plans across enemy lines. The spread spectrum radio technologies often used in today's WLANs were also originally patented during the era of World War II, although they were not implemented until almost two decades later.

In 1970, the University of Hawaii developed the first wireless network, called ALOHAnet, to wirelessly communicate data between the Hawaiian Islands. The network used a LAN communication Open Systems Interconnection (OSI) layer 2 protocol called ALOHA on a wireless shared medium in the 400 MHz frequency range. The technology used in ALOHAnet is often credited as a building block for the Medium Access Control (MAC) technologies of Carrier Sense Multiple Access with Collision Detection (CSMA/CD) used in Ethernet and Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) used in 802.11 radios. You will learn more about CSMA/CA in Chapter 8, “802.11 Medium Access.”

In the 1990s, commercial networking vendors began to produce low-speed wireless data networking products, most of which operated in the 900 MHz frequency band. The Institute of Electrical and Electronics Engineers (IEEE) began to discuss standardizing WLAN technologies in 1991. In 1997, the IEEE ratified the original 802.11 standard that is the foundation of the WLAN technologies you will be learning about in this book.

This legacy 802.11 technology was deployed between 1997 and 1999 mostly in warehousing and manufacturing environments for the use of low-speed data collection with wireless barcode scanners. In 1999, the IEEE defined higher data speeds with the 802.11b amendment. The introduction of data rates as high as 11 Mbps, along with price reductions, ignited the sales of wireless home networking routers in the small office, home office (SOHO) marketplace. Home users soon became accustomed to wireless networking in their homes and began to demand that their employers also provide wireless networking capabilities in the workplace. After initial resistance to 802.11 technology, small companies, medium-sized businesses,...