sybex ccna 640-802 chapter 14: cisco wireless technologies instructor & todd lammle
TRANSCRIPT
Sybex CCNA 640-802 Chapter 14: Cisco Wireless
TechnologiesInstructor & 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
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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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Wireless agencies and standards
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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• 802.11n: Higher throughput improvements
using MIMO (multiple input, multiple output antennas)
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802.11 CSMA/CA
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ISM 2.4 Ghz Channels
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UNII 5Ghz Band (802.11a) 54 mbps
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Range Comparisons
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2.4GHz/5GHz (802.11n)
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The following three vital items are combined in 802.11n 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 802.11
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Ad Hoc mode
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Basic Service Set (BSS)
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Extended Service Set
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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
• 802.11i• Encryption Methods
– Temporal Key Integrity Protocol (TKIP)– AES
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WPA/WPA/802.11i summary
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Wireless Security Implementations
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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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