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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
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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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