Wi- Fi is Wireless Ethernet. This is a recent technology which is available for connecting many nodes within some specified radius. These nodes communicate each other through an Access Point (AP). These access points are set up few meters from each other, so that all the nodes in the locality are connected. Wi-Fi is of high speed access and it is largely replacing the high speed LANs. Other networks like ATM, Ethernet and high speed LANs are connected through a portal, a point connecting two different networks. These nodes along with the access point form the Base Service Set (BSS).