Sybex CCNA Chapter 14: Cisco Wireless Technologies Instructor & Todd Lammle

Chapter 14 Objectives The CCNA Topics Covered in this chapter include: What is a WLAN? IEEE Standards CSMA/CD ISM channels UNII Band BSS/ESS Wireless Security 2

Wireless LAN’s Transmitting a signal using the typical 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

Wireless agencies and standards 4

Unlicensed Frequencies 5

Standards Here are the most popular standards in use today: b: 2.4Ghz, maximum bandwidth of 11Mbps 802.1g: 2.4Ghz, up to 54Mbps a: 5Ghz, up to 54Mbps n: Higher throughput improvements using MIMO (multiple input, multiple output antennas) 6

CSMA/CA 7

ISM 2.4 Ghz Channels 8

UNII 5Ghz Band (802.11a) 54 mbps 9

Range Comparisons 10

2.4GHz/5GHz (802.11n) 11 The following three vital items are combined in n to enhance performance: At the Physical layer, the way a signal is sent is changed, enabling reflections and interferences to become an advantage instead of a source of degradation. Two 20Mhz-wide channels are combined to increase throughput. At the MAC layer, a different way of managing packet transmission is used.

Comparing

Ad Hoc mode 13

Basic Service Set (BSS) 14

Extended Service Set 15

Wireless Security Open Access SSIDs, WEP, and MAC Address Authentication Wi-Fi Protected Access (WPA) –WPA or WPA2 Pre-Shared Key –WPA or WPA2 Enterprise i Encryption Methods –Temporal Key Integrity Protocol (TKIP) –AES 16

WPA/WPA/802.11i summary 17

Wireless Security Implementations 18

Summary –Summary –Open your books and go through all the written labs and the review questions. –Review the answers in class. 19