Wi-Fi

Wi-Fi (short for wireless fidelity) is a category of networks that use radio signals instead of wires to connect computers and other devices. Another name for Wi-Fi is wireless Ethernet, because Wi-Fi uses many of the same data-handling rules and specifications as a wired Ethernet network. However, every Wi-Fi packet must include additional handshaking data, so the overall data transfer speed is often slower than a conventional Ethernet link.

Wi-Fi offers several advantages: It doesn't need cables to connect every network node, so it's often easier to install and use than a wired network connection. Rather than string cables through walls and provide a network outlet at every desk, you can distribute access to the network through antennas in between each computer and a base station (an access point) in a central location. When you travel with a laptop computer, a handheld PDA (personal digital assistant), or a mobile Internet device, such as a BlackBerry or an iPhone, you can often connect it to the Internet via Wi-Fi by simply turning it on.

Many home and small business networks use a combination of Ethernet and Wi-Fi; the Wi-Fi base station doubles as a connection point for Ethernet cables, so the same LAN includes both wired and wireless nodes. Chapter 8 contains information about installing and using Wi-Fi network links.