A Wi-Fi® or WiFi® network is the most familiar type of wireless network used to connect computers and share online access at home or at the office. A WiFi® network does not require cabling, but broadcasts network traffic over radio waves. It does this using a central device that is often three components in one: a network hub, router, and high-speed Internet modem. For simplicity we'll refer to this device as a router, though in some cases the router, which has a built-in hub, is purchased separately from the modem.
Each machine on a WiFi® network must have an installed WiFi® card or an external WiFi® adapter. These devices incorporate a receiver and transmitter to send and receive data over the network to the router. Broadcast range varies up to 300 feet (~100m) or more, but is fairly centralized, creating what is termed a local area network (LAN). The WiFi® router, cards and adapters use a common language or protocol to communicate that is compliant with a standard known as IEEE 802.11.
Within the 802.11 standard there are different generations of protocols, each designated by an additional letter. Generations to date include 802.11a, 802.11b, 802.11g and 802.11n. The first two flavors are now legacy, but as of spring 2009, 802.11g is still in widespread use with the newer and faster 802.11n on the road to replacing it.
All WiFi® components in the network must support the same flavor or generation of 802.11 standards to communicate. If the router only supports 802.11g, the WiFi® cards and adapters must also support 802.11g. If the router supports 802.11n, the cards and adapters must also support 802.11n.
Some routers, cards and adapters manufactured during transitional periods between changing standards will be designed to support both the current and the new protocol for maximum flexibility. These devices will be more expensive since the “g” and “n” networks utilize different frequency bands, requiring two radios instead of just one.
Components made for a WiFi® network might be certified by the Wi-Fi Alliance. Certification ensures the product is fully compliant with the standard(s) it supports. Only a wireless network that has certified components is a true Wi-Fi® network by technical standards, as Wi-Fi® is a trademark of the Wi-Fi Alliance. However, “WiFi” or “wifi” has been generalized to mean any wireless network that complies with 802.11 whether components are officially certified or simply marketed as compatible.
When setting up a WiFi® network it’s best to use the newest technology available in order to future-proof the investment. For home use, non-certified WiFi® components might save a little money and will more than likely do the job just fine. If setting up a wireless network for a business, a true Wi-Fi network with certified components that have been fully tested and are known to be fully compliant might be a more prudent choice.
The 802.11 standards used in a WiFi® network differentiate it from other types of wireless communications that use radio waves, such as Bluetooth® networks. Bluetooth uses a weaker, less robust radio band that travels a much shorter distance of up to about 30 feet (~10m). Bluetooth is primarily designed to connect battery-operated personal devices to one another for interoperability, creating a personal area network (PAN). Bluetooth might be used to pass files from a cell phone to a computer, to synchronize a personal digital assistant with a laptop, or to connect a wireless headset with a cell phone or MP3 player.