Chapter 1: What is Wi-Fi

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Overview

"Wi-Fi" is a play on the old audio term "Hi-Fi" (high fidelity). The term also has been trademarked by the Wi-Fi Alliance (formerly the Wireless Ethernet Compatibility Alliance). Today, Wi-Fi is most commonly used to describe a wireless local area network based on the IEEE 802.11 series of standards, which is a set of wireless technical specifications issued by the Institute of Electrical and Electronic Engineers (IEEE). The IEEE is an international professional organization for electrical and electronics engineers, with formal links with the International Organization for Standardization (more commonly known as the "ISO").

The IEEE 802.11 standards specify an "over-the-air" interface consisting of radio frequency (RF) technology to transmit and receive data between a wireless client and a base station or access point (an "infrastructure" configuration), as well as among two or more wireless clients that happen to be within communications range of each other (an "ad hoc" configuration).

The IEEE 802.11 standards resolve compatibility issues between manufacturers of wireless networking equipment operating in specific frequency bands within the unlicensed spectra of 2.4 GHz and 5 GHz. (Unlicensed spectrum refers to airwaves that haven't been allocated to an exclusive user.) This wireless, flexible data communications system can be implemented either as an extension to, or as an alternative for, a wired local area network (LAN). As such, it is a wireless networking standard that's accepted worldwide and, consequently, has rapidly gained acceptance as an alternative to conventional wireline technologies.

The term "Wi-Fi" began life a few years ago as the IEEE 802.11 High Rate (HR) Standard, which later became known as the IEEE 802.11b standard. Originally, "Wi-Fi" was used only in place of the 802.11b standard (operating at 2.4 GHz and 11 Mbps), in the same way that the term "Ethernet" is used in place of the wired LAN standard, IEEE 802.3. However, in October 2002, the Wi-Fi Alliance extended the "Wi-Fi" trademark to include both 802.11b and its higher-bandwidth brother, 802.11a (54 Mbps).

In case you're wondering, 802.11g will also fall under the Wi-Fi banner. Furthermore, since in many ways, 802.11g is a higher-bandwidth version of the 802.11b specification, the Wi-Fi Alliance also has stated that when it does certify 802.11g products as interoperable, the organization won't label them "802.11g." Instead, it plans on calling such products "54 Mbps 802.11b," because focus groups of potential customers have shown that users are confused by the alphabet soup nature of the IEEE's designations for the various 802.11 standards.

Note 

Specific groups, known as "Task Groups" inside the 802.11 standards body oversee enhancements ranging from bandwidth to specific portions of the 802.11 standard. The appearance of each new "flavor" of the technology results in a new suffix to 802.11, i.e. 802.11a, 802.11b, up to 802.11n. While there is a method for the IEEE standards naming scheme, the alphanumeric nature of these standards can be confusing, which is why the moniker "Wi-Fi" caught on. A complete technical discussion of each individual specification or standard can be found in Chapter 6.

Ultimately, the term "Wi-Fi" will probably end up as a generic description of all 802.11 networks, in much the same way that "Ethernet" is used to describe all IEEE 802.3 networks. Coincidentally, since 802.11 networks are considered wireless extensions of wired Ethernet, they can handle conventional networking protocols such as TCP/IP, AppleTalk and PC file sharing standards.

The opportunity for wireless data communication in the United States and elsewhere is huge. According to the research firm Gartner, Inc., as revealed in its Dataquest Market Analysis Perspective entitled, "Wireless Data in the United States: Pieces of the Puzzle are Missing, but a Picture is Taking Shape," more than 25 million of the U.S.'s 112.1 million workforce have a mobile job requirement and that number is steadily increasing.

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