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Instructor & Todd Lammle

Instructor & Todd Lammle. Sybex CCNA 640-802 Chapter 12: Wireless Networks. Chapter 12 Objectives. The CCNA Topics Covered in this chapter include: What is a WLAN? IEEE Standards CSMA/CD ISM 2.4Ghz channels UNII Band BSS/ESS Wireless Security. 2. Wireless LAN’s.

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Instructor & Todd Lammle

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  1. Instructor & Todd Lammle Sybex CCNA 640-802 Chapter 12: Wireless Networks

  2. Chapter 12 Objectives The CCNA Topics Covered in this chapter include: • What is a WLAN? • IEEE Standards • CSMA/CD • ISM 2.4Ghz channels • UNII Band • BSS/ESS • Wireless Security 2

  3. Wireless LAN’s • Transmitting a signal using the typical 802.11 specifications works a lot like it does with a basic Ethernet hub: They’re both two-way forms of communication, and they both use the same frequency to both transmit and receive, often referred to as half-duplex. • Wireless LANs (WLANs) use radio frequencies (RFs) that are radiated into the air from an antenna that creates radio waves. 3

  4. Unlicensed Frequencies • 900MHz, 2.4GHz: Industrial, Scientific, and Medical (ISM) bands • 5GHz: Unlicensed National Information Infrastructure (UNII) band. 4

  5. 802.11 Standards Here are the most popular standards in use today: • 802.11b: 2.4Ghz, maximum bandwidth of 11Mbps • 802.11g: 2.4Ghz, up to 54Mbps • 802.11a: 5Ghz, up to 54Mbps 5

  6. 802.11b CSMA/CA RTS: Request to Send CTS: Clear to Send 6

  7. ISM 2.4 Ghz Channels • 14 different channels (each 22MHz) released by the FCC in the 2.4GHz range • 3 non-overlapping channels 7

  8. UNII 5Ghz Band • 12 non-overlapping channels (each 20MHz) released by the FCC in the 5GHz range 8

  9. Range Comparisons 9

  10. BSS/ESS 10

  11. Wireless Security All Wi-Fi Certified wireless LAN products are shipped in "open-access" mode, with their security features turned off. • SSID (Service Set Identifiers), WEP (Wired Equivalency Protocol) and MAC authentication • 802.11i • WPA (Wi-Fi Protected Access) and WPA 2 11

  12. Summary • Summary • Open your books and go through all the written labs and the review questions. • Review the answers in class. 12

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