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Wireless Local Area Networks (WLANs)



Wireless Local Area Networks (WLANs)
Wireless LANs, or WLANs, use radio frequency (RF) technology to transmit and receive data over the air. This minimizes the need for wired connections. WLANs give users mobility as they allow connection to a local area network without having to be physically connected by a cable. This freedom means users can access shared resources without looking for a place to plug in cables, provided that their terminals are mobile and within the designated network coverage area. With mobility, WLANs give flexibility and increased productivity, appealing to both entrepreneurs and to home users. WLANs may also enable network administrators to connect devices that may be physically difficult to reach with a cable.
The Institute for Electrical and Electronic Engineers (IEEE) developed the 802.11 specification for wireless LAN technology. 802.11 specifies over-the-air interface between a wireless client and a base station, or between two wireless clients. WLAN 802.11 standards also have security protocols that were developed to provide the same level of security as that of a wired LAN.
The first of these protocols is Wired Equivalent Privacy (WEP). WEP provides security by encrypting data sent over radio waves from end point to end point.
The second WLAN security protocol is Wi-Fi Protected Access (WPA). WPA was developed as an upgrade to the security features of WEP. It works with existing products that are WEP-enabled but provides two key improvements: improved data encryption through the temporal key integrity protocol (TKIP) which scrambles the keys using a hashing algorithm. It has means for integrity-checking to ensure that keys have not been tampered with. WPA also provides user authentication with the extensible authentication protocol (EAP).
Wireless Protocols
Specification
Data Rate
Modulation Scheme
Security
802.11
1 or 2 Mbps in the 2.4 GHz band
FHSS, DSSS
WEP and WPA
802.11a
54 Mbps in the 5 GHz band
OFDM
WEP and WPA
802.11b/High Rate/Wi-Fi
11 Mbps (with a fallback to 5.5, 2, and 1 Mbps) in the 2.4 GHz band
DSSS with CCK
WEP and WPA
802.11g/Wi-Fi
54 Mbps in the 2.4 GHz band
OFDM when above 20Mbps, DSSS with CCK when below 20Mbps
WEP and WPA
The Internet and Beyond
More than just a technology, the Internet has become a way of life for many people, and it has spurred a revolution of sorts for both public and private sharing of information. The most popular source of information about almost anything, the Internet is used daily by technical and non-technical users alike.

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