Chapter12ccna

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

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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.

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Unlicensed Frequencies

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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

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802.11b CSMA/CD

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ISM 2.4 Ghz Channels

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UNII 5Ghz Band

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Range Comparisons

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BSS/ESS

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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

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Summary

– Summary– Open your books and go through all the

written labs and the review questions.– Review the answers in class.

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