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

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

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 6 RTS: Request to Send CTS: Clear to Send

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

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

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