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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