A Drive-By Wi-Fi Overview

Wi-Fi is a technology that connects computers (and other computerish devices like printers and game consoles) without wires, in a particular and standardized way. A Wi-Fi connection moves data files between devices precisely as a wired connection would, albeit not as quickly. From the perspective of your computer, there is no difference between a connection created with cables and a connection created with Wi-Fi equipment. To Windows, a network is a network. Windows doesn't care how the hookup is accomplished.

Even though it doesn't use cables, Wi-Fi is nonetheless a hardware solution. Each computer or other device that will connect to a Wi-Fi network requires a small device called a client adapter. This is usually a plug-in card of some kind (there are several different kinds) but can also be a USB (Universal Serial Bus) device. In addition to one client adapter for each connected device, a Wi-Fi network also requires a centrally located device called an access point. The access point is Grand Central Station for the wireless network, and coordinates the connections among all the various connected computers and other devices. To send data to one another, client adapters must transmit their data to the access point, which then relays it to the client adapters to which the data is addressed.

Client adapters do have the power to connect directly with one another, but this feature is less useful than it sounds and few people in my acquaintance use it much.

Virtually all Wi-Fi networks are set up to work with an Internet connection, ideally a high-speed broadband connection like cable or DSL. Connecting a Wi-Fi network to the Internet requires some additional hardware, specifically something called a router. A router is a device that connects one network to another network, and the Internet is also a network. The router sits between your (small) network and the (huge) Internet, directing traffic and perhaps more importantly, limiting the sorts of connections that occur between your network and the Internet. There is a class of products that combine a router and a Wi-Fi access point into a single box. These are sometimes called wireless gateways or wireless residential gateways. A gateway makes it very easy to share an Internet connection among several machines around your house or small office.

The connections between Wi-Fi adapters are accomplished with microwave-frequency radio waves. There is a small microwave transmitter and receiver in every client adapter and access point. This is obvious in some Wi-Fi devices, which come with small antennas. The strength of the microwave energy used is so minuscule as to not be any sort of health risk. Wi-Fi, in fact, uses less powerful transmitters than the cellphones we mash up against our faces most of the livelong day, and its microwave energy is almost a million times less powerful than the microwave energy used in microwave ovens. (It's also helpful that Wi-Fi devices aren't held right up against the side of your head!)

The range of Wi-Fi devices is fairly short, no more than a couple hundred feet at very best, and usually less. (Within a building, it can be as little as 80 or 100 feet.) This range can be increased when necessary by using special antennas and by careful placement of access points. For larger homes and especially offices, it's possible to build Wi-Fi networks with multiple access points, connected by cables, allowing seamless roaming access anywhere in the building where one of the network's access points is within range. If designed and installed carefully, such a network can allow people to carry their laptops and PDAs (while their batteries hold out) anywhere in the building and never lose their connections to the network. Roaming is considered a 'premium' feature and costs more, but it's there if you decide you need it.

Wi-Fi has been around for several years, but until fairly recently the gear was so expensive that consumers couldn't afford using Wi-Fi in home networks. That was then. These days, client adapters have a typical street price of $35 to $75, and access points can be had for $80 to $120. Wireless residential gateways cost in the neighborhood from $100 to $140. Rebates and sales can bring prices down even further, and many people have equipped their home Wi-Fi networks for well under $200.

Among the most enthusiastic users of Wi-Fi networking are business travelers, who are taking advantage of the proliferation of Wi-Fi hotspots at coffee shops, hotels, conference centers, and even city parks, to connect their laptops to the Internet while on the road. A hotspot is simply a wireless access point that is connected to the Internet and available to the general public. Most of these hotspots are feebased, but many are part of community networks and may be used for free.

Among computer enthusiasts, Wi-Fi has become a hobby with a vigor I haven't seen in computing for quite a few years. People are building Wi-Fi antennas out of coffee cans and potato chip cans, and modifying and enhancing Wi-Fi gear in a lot of really creative ways. I'll speak to that phenomenon later in this book as well.

Because Wi-Fi data is passed around the network on radio waves, it's possible for outsiders to listen in unless you take certain precautions like turning on Wi-Fi's built-in encryption system. Security is a very big issue in Wi-Fi, and I devote four whole chapters (Chapters 11 through 14) to security later in this book. Please read them before you install your Wi-Fi network!

Why 'Wi-Fi?'

The curse of emerging technologies is 'soft standards.' Standards are supposed to ensure that devices made by different vendors can work with one another, but sometimes things don't work out, and subsequent chaos (and angry consumers) can sink a promising technology before it ever achieves critical mass. 802.11b is a fairly young standard (it was only finalized in 1999) and as communications standards go is relatively complex. Early in the life of 802.11b a group called the Wireless Ethernet Compatibility Alliance (WECA) created a logo-certification program for 802.11b devices. The 802.11b certification program was named 'Wi-Fi,' for 'Wireless Fidelity,' hearkening back to the Hi-Fi audio systems of the 1950s. WECA began testing vendor products for adherence to the 802.11b standard, and products that pass may display the Wi-Fi logo. Consumers are encouraged to see the Wi-Fi logo as indication that a product is fully compatible with the 802.11b standard. In this, it's directly comparable to the Microsoft Windows logo program that allows software vendors to indicate that their products have been tested for Windows compatibility.

As odd a term as it is, Wi-Fi was an unqualified success, with many millions of units now out there in the hands of consumers. For that reason, WECA changed its name to the Wi-Fi Alliance in mid-2002. The WECA acronym remains mostly in its Web address: www.weca.net.

There are still weak spots and soft spots-and a few empty spots-in the 802.11b standard. Additional task groups have been convened by the standards-setting body (a group called the IEEE, for the Institute of Electrical and Electronic Engineers) to fill in the holes in the 802.11b standard. Many of these task groups are still working, and thus the problems they are in the process of solving aren't quite solved yet. I'll be mentioning quite a few of these task groups later on in this book, and will summarize the whole lot of them in the IEEE Task Group Encyclopedia at the end of this book.

IEEE 802.11: How It Came About

Wireless networking has been around for some time. The University of Hawaii pioneered the wireless LAN idea with an experiment called ALOHANET way back in 1971. ALOHANET was an expensive, big-iron system solving a serious problem-trading data among university sites scattered across four islands-but the principles are the same as those that govern data-trading between the machine in your den and the one in your kids' rooms. Sun Microsystems created a prescient hand-held mini-tablet computer called the Star 7 in 1992, which included 900 MHz wireless networking, but it never made it to market. (Sun, like my alma mater Xerox, has a bad habit of pioneering technologies it never markets, and then watching other companies make their fortunes doing the same things ten years later.)

The first wireless LAN technology I ever saw was a 900 MHz UHF ISM band WaveLAN system, which was demonstrated at a COMDEX trade show in 1994. The demo consisted of a laptop with a PCMCIA card (physically identical to today's Wi-Fi PCMCIA cards) networked to a PC about ten feet away. The data rate was 1.6 Mbps, which seemed mighty fast at the time. I wanted one, but couldn't afford it-both ends of the connection would have cost me almost $2,000!

The WaveLAN system worked, and worked well. It was expensive, but the people who needed it needed it badly, and WaveLAN and numerous systems like it became a small and little-known sliver of the networking industry, mostly used by highpriced consultants to create proprietary solutions to specific problems, usually for big corporations. Everybody had a different scheme for bundling data into packets and spinning it off into the airwaves, and nobody's scheme talked to anybody else's scheme. That was the way all the vendors in that era wanted it; their customers had money and were willing to spend lots of it, so there was bottom-line value in keeping them captive to a proprietary system.

In 1997, the Institute of Electrical and Electronic Engineers (IEEE) released their 802.11 standard for wireless networking, and everything changed.

The Magic of (IEEE) Numbers

The IEEE is a large and influential body of engineers that does a great many things, but what they do that matters most (in my view) is develop and establish technology standards. Standards are important because they enlarge markets, and make it possible for technologies manufactured by different vendors to interoperate and communicate with one another. This is especially important in the area of computer communications, in which the whole idea is to get the machinery talking.

The IEEE has been doing this for a long time, and in many areas, some of them pretty far removed from computing. The process, however, happens in pretty much the same way: The IEEE establishes a 'working group' to pursue a particular standards issue. The group meets and hashes out the issue, sometimes for several years, and eventually creates a document that defines or modifies a standard. The document is then sent out to interested IEEE members for a mail vote. Based on the results of that balloting, the document is either sent back for further work or is adopted as a new (or modified) standard.

Working groups are given numbers. When a working group is tasked with modifying an existing standard that already has a number, the group is given a new number that has either additional digits or else letters appended to the existing standard number.

The 802 Standard

The mother of all IEEE networking standards is the 802 standard, which was under discussion for most of ten years. This standard, which was finally adopted in 1990, governed the lowest level of networking functions: Physical and link control. (These are the bottom two layers of the Open Systems Interconnection model for networking. If you're reasonably technically inclined, the OSI model is worth some study, as it is enormously useful in keeping the countless network standards and mechanisms separated and correctly related. Unfortunately, it's a big subject, and I cannot cover it in detail in this book.)

The overall networking standard was numbered 802. Different standard areas within the greater 802 standard were given decimal qualifiers. The original Ethernet protocol invented by Xerox in the early 1970s was refined slightly and given the number 802.3 when it was standardized as part of the 802 definition. The Token Ring networking technology introduced by IBM in the mid-1980s was given the number 802.5.

In the mid-1990s, the IEEE created a working group to develop a standard for wireless networking. The working group was given the number 802.11 (which is the eleventh working group under the 802 standard, not a refinement of 802.1) and it was adopted in 1997.

The original 802.11 standard specified a frequency of 2.4 GHz with available data rates of 1 and 2 megabits per second (Mbps). 802.11 products were marketed almost immediately, but were slow to be accepted, at least in part because the data rates were so slow compared to contemporary wired networks. 802.3 wired Ethernet technology had gone from 10-Base-T (10 Mbps) to 100-Base-T (100 Mbps) at about the same time, and 2 Mbps looked pretty grim by comparison. Furthermore, radio hardware that could work effectively at 2.4 GHz frequencies was still pretty expensive at that time. The end result was that 802.11 networking did not exactly set the world on fire. The IEEE almost immediately created several task groups to begin work on improving 802.11, especially in the area of data rate.

The fire came in 1999, when the 802.11b amendment to 802.11 was accepted and published. 802.11b was formerly known as '802.11 High Rate' because it added 5.5 Mbps and 11 Mbps data rates to the existing 1 and 2 Mbps rates. 802.11b was the right spec at the right time, and most manufacturers who had been selling 802.11 hardware wasted no time updating their products to adhere to the new 802.11b standard. Although still fairly expensive (I paid $1,200 for an 802.11b access point in 1999) the higher bit rates were enough to put 802.11b wireless networking on the radar screens of large and mid-sized companies that could afford it.

Apple Pioneers Consumer Wi-Fi

High prices kept 802.11b networking out of the hands of ordinary consumers (quite apart from technowhackos like me) until 2000, when Apple's AirPort wireless networking system took prices down into consumer territory. After that, it was le deluge, especially once an industry consortium called the Wireless Ethernet Compatibility Alliance (WECA) created the Wi-Fi compatibility testing program. (WECA changed its name in 2002 to the Wi-Fi Alliance.) These days, wireless access points can be had for under $100, and client adapters for as little as $50.

802.11b remains the most significant 802.11 standard extension, but others have now been released and still more are in process. 802.11a products reached the market late in 2001, with still-faster bit rates (though much higher prices), and 802.11g products are on the horizon. (Note that the letters are assigned when a task group is formed, not when the eventual standard is finalized and adopted. The 802.11a and 802.11b task groups were formed at the same time, but the 802.11b folks had a less difficult job to do and finished first.)

Some 802.11 task groups are addressing only specific features of 802.11 networking, like encryption. Not all letters in the 'alphabet soup' are full upgrades to the whole 802.11 idea.

Competing wireless network technologies are out there, but none have the same sense of destiny that 802.11 has. A technology called HomeRF hit the market early in 2000, and although slower than Wi-Fi, it was at its introduction much cheaper, and has arguably better security and built-in machinery for handling telephone calls. (In a sense, HomeRF merges wireless LANs and cordless phones.) However, HomeRF never achieved what 802.11 achieved: The magic of an IEEE standards designation.

The IEEE imprimatur, with its respect among major industry hardware vendors, is what makes the magic happen. Unless or until a directly competing technology gets that imprimatur, I don't see anything knocking 802.11 from its leadership position in wireless networking.



Jeff Duntemann's Drive-By Wi-Fi Guide
Jeff Duntemanns Drive-By Wi-Fi Guide
ISBN: 1932111743
EAN: 2147483647
Year: 2005
Pages: 181

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