What is Wi-Fi

Wi-Fi is a marketing phrase that is short for wireless fidelity. It compliments the over geekafied moniker IEEE 802.11x, where x is a,b, or g. When you sit down at a networked desktop computer it is connected by a network cable to a hub, router, or switch. The computer's network interface card sends zeros and ones down the cable by changing the voltage on the wires from +5 volts to -5 volts in a prearranged cadence. Wi-Fi simply replaces these cables with small low powered two way radios. Instead of changing voltage on a wire it encodes the zeros and ones by laying an alternating radio signal over a constant existing signal, again in a prearranged cadence. The alternating signal encodes zeroes and ones on the radio waves. This is an over simplification, but you get the idea. The 802.11b specification allows for the wireless transmission of approximately 11 Mbps of raw data at distances from several dozen to several hundred feet over the 2.4 GHz unlicensed band. The distance depends on impediments, materials, and line of sight.

Thanks, you say. So what does this mean for me? Well, it means you can slip a $78 PC card into your laptop or PDA and be as connected to the Internet or your corporate network as if you were still tied to your desk. There are a handful (6 at last count) of laptops that have WiFi built in. By the middle of 2002 IBM states that all of their laptops will have Wi-Fi built in. There are even USB devices that will get you on a WiFi network. This is good. For some real world examples please review our industry solutions section.

This specification started to appear in commercial form in mid-1999, with Apple Computer's introduction of its AirPort components, manufactured in conjunction with Lucent's WaveLAN division. (The division changed its named to Orinoco and was spun off to the newly formed Agere corporation with a variety of other Lucent assets in early 2001.)

802.11b is an extension of Ethernet to wireless communication, and as such is ecumenical about the kinds of data that pass over it. It's primarily used for TCP/IP, but can also handle other forms of networking traffic, such as AppleTalk or PC filesharing standards.

Each radio may act, depending on software, as a hub or for computer-to-computer transmission, but it's much more common that a WLAN (wireless local area network) installation uses one or more access points, which are dedicated stand-alone hardware with typically more powerful antennae. The access point often includes routing, DHCP server, NAT, and other features necessary for small to large business operation. Similar to access points are residential gateways, a new class of device, which offers similar features but without the advanced management required for corporate networks or high-traffic installations.

The standard is backwards compatible to earlier specifications, known as 802.11, allowing speeds of 1, 2, 5.5 and 11 Mbps on the same transmitters.

Several new, incompatible protocols are in the process of being released, including 802.11a (54 Mbps over the 5 GHz band), 802.11g (22 Mbps over 2.4 GHz), and Texas Instruments' PBCC 22 Mbps standard. The good news is, the silicon is getting so powerful that several 802.11a/b chipsets have just been released.

An industry group known as the Wireless Ethernet Compatibility Alliance (WECA) certifies its members equipment as conforming to the 802.11b standard, and allows compliant hardware to be stamped Wi-Fi compatible. The Wi-Fi seal of approval is an attempt at a guarantee of intercompatibility between hundreds of vendors and thousands of devices. (The IEEE does not have such a mechanism, as it only promulgates standards.)

802.11b has become the only standard deployed for public short-range networks, such as those found at airports, hotels, conference centers, and coffee shops and restaurants. Several companies currently offer paid hourly, session-based, or unlimited monthly access via their deployed networks around the U.S. and internationally.