Wireless LAN is a wireless local area network that uses radio waves as a medium tranmisinya: the last link used is wireless, to give a network connection to all users in the surrounding area. Area can be located from a single room to the entire campus. The backbone network usually uses Kable, with one or more network access points connect wireless users to the wired network.
Wireless LAN is a wireless network that uses radio frequency for communication between computers and finally the access point that is the basis of two-way radio transiver typical working in bandwidth 2.4 GHz (802.11b, 802.11g) or 5 GHz (802.11a) . Most equipment has a qualification Wi-Fi, the IEEE 802.11b or IEEE 802.11g accommodation and offers several levels of security such as WEP or WPA and.
In a cable network, one can often, in some degree, access to the network is physically closed. Geographical distance from the wireless network will be significantly larger, more often than enclosed office or home; neighbors or arbritrary violators may be able to smell and all traffic and non-authority access internal network resources as the Internet, it might send spam or perform activities illegal use of IP address owners, if security is not made seriously.
Some advocates will see all available access points openly available to the public, on the basis that everyone would benefit from when the traffic gets online.
Source :http://id.wikipedia.org/wiki/LAN_nirkabel