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

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 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

Unlicensed Frequencies 4

802.11 Standards Here are the most popular standards in use today: 802.11b: 2.4Ghz, maximum bandwidth of 11Mbps 802.1g: 2.4Ghz, up to 54Mbps 802.11a: 5Ghz, up to 54Mbps 5

802.11b CSMA/CD 6

ISM 2.4 Ghz Channels 7

UNII 5Ghz Band 8

Range Comparisons 9

BSS/ESS 10

Wireless Security All Wi-Fi Certified wireless LAN products are shipped in "open-access" mode, with their security features turned off. SSID, WEP and MAC authentication 802.11i WPA and WPA 2 11

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