Wi-Fi, or Wireless Fidelity is freedom :it allows you to connect to the internet from your couch at home, in a hotel room or a conferance room at work without wires . Wi-Fi is a wireless technology like a cell phone. Wi-Fi enabled computers send and receive data indoors and out; anywhere within the range of a base station. And the best thing of all, it is fast.
However you only have true freedom to be connected any where if your computer is configured with a Wi-Fi CERTIFIED radio (a PC card or similar device). Wi-Fi certification means that you will be able able to connect anywhere there are other Wi-Fi CERTIFIED products - whether you are at home ,office , airports, coffee shops and other public areas equipped with a Wi-Fi access availability.Wi-Fi will be a major face behind hotspots , to a much greater extent.More than 400 airports and hotels in the US are targeted as Wi-Fi hotspots.
The Wi-Fi CERTIFIED logo is your only assurance that the product has met rigorous interoperability testing requirements to assure products from different vendors will work together. The Wi-Fi CERTIFIED logo means that it is a "safe" buy.
Wi-Fi certification comes from the Wi-Fi Alliance, a non profit international trade organisation that tests 802.11 based wireless equipment to make sure that it meets the Wi-Fi standard and works with all other manufacturer's Wi-Fi equipment on the market. The Wi-Fi Alliance (WELA) also has a Wi-Fi certification program for Wi-Fi products that meet interoperability standards. It is an international organisation devoted to certifying interoperability of 802.11 products and to promoting 802.11as the global wireless LAN std across all market segment.
IEEE 802.11 ARCHITECTURES
In IEEE's proposed standard for wireless LANs (IEEE 802.11), there are two different ways to configure a network: ad-hoc and infrastructure. In the ad-hoc network, computers are brought together to form a network "on the fly." As shown in Figure 1, there is no structure to the network; there are no fixed points; and usually every node is able to communicate with every other node. A good example of this is the aforementioned meeting where employees bring laptop computers together to communicate and share design or financial information. Although it seems that order would be difficult to maintain in this type of network, algorithms such as the spokesman election algorithm (SEA)  have been designed to "elect" one machine as the base station (master) of the network with the others being slaves. Another algorithm in ad-hoc network architectures uses a broadcast and flooding method to all other nodes to establish who's who.