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.
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.