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How Secure Is Your Wireless Network? Safeguarding Your Wi-Fi LAN by CCNA Lee Barken - CISSP MCP, CPA

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802.11a

At the same time 802.11b was approved, another high-speed option, 802.11a, also appeared. 802.11a operates in the 5-GHz spectrum. It is not compatible with 802.11b, but it does not interfere with it. (A and B networks can coexist in the same physical space.) Think of it like this: You can hold a cell phone in one hand and a walkie-talkie in the other hand. They can both work at the same time, just not with each other. 802.11a (see Table 2.3) has 12 non-overlapping channels that operate at 54 Mbps, but the coverage area is much smaller then 802.11b.

Table 2.3. 802.11a specifications.
Frequency:5 GHz
Channels: 12 USA
Speed: 54 Mbps
Range: Appx. 60 feet (varies)
Encoding Scheme: OFDM
Modulation Technique: BPSK (6 & 9 Mbps)

QPSK (12 & 18 Mbps) ...

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