Friday, May 02, 2003
Wireless Computer Networking Takes Off
“Wireless” literally means “without wires.” The British used it in the past as a synonym for “radio.” Now the term is cropping up in the computing world: wireless mice and keyboards, wireless Internet, wireless networking. To make matters even more confusing, it comes in a proliferation of flavors (Wi-Fi, AirPort [AirMac in Japan], Bluetooth), together with the associated alphabet soup (802.11b and all the rest). What does it all mean?
What Wireless Used to Mean
Until recently, wireless communication between equipment used infrared signals, the same technology used by most remote control devices to operate audiovisual equipment. For example, many personal digital assistants (PDAs) incorporate an infrared transceiver to enable the “beaming” of data to similarly equipped siblings and synchronization with computers with an infrared port. Some cellular telephones and public telephones also have this capability, allowing wireless connection to the Internet, and it is sometimes possible to print using a printer equipped with an infrared connection.
I say “sometimes” for a number of reasons. First, and most important, infrared is a line-of-sight technology. An object coming between the computer and the printer disrupts the print queue. You can therefore forget about printing on a printer in the next room if a wall is in the way. Second, three meters is the maximum practical operating range for most infrared devices. This distance is suitable for swapping electronic business cards between PDAs but useless for more demanding applications. Third, infrared is slow. Under excellent conditions, infrared can transmit about 120,000 bits/second (or about 10,000 characters/second). This figure sounds like a lot, until you realize that 120,000 bits is the size of a medium-sized Web graphic or a single-page Word file. Therefore, infrared is not really suitable for moving large amounts of data between devices. For keyboards and mice, this slow speed is no disadvantage (how many people do you know who type at 10,000 characters/second?), but the line-of-sight limitation has always constrained the practical implementation of infrared technology.
Biting Off What We Can Chew-Today’s “Wireless”
Today, when we refer to “wireless,” we mean high-frequency radio wave technology.
With the development of new chip technologies to empower very local digital data streams, the system known as Bluetooth (named after Harald Blatand, the Viking king reputed to have united Norway and Denmark) has the potential to replace infrared as a low-cost wireless medium. Embedded technology can be used to identify other Bluetooth-equipped devices and exchange data between them at more than ten times the speed of infrared transmission. The distance at which Bluetooth devices can be separated is only two to three times that of infrared, but the line-of-sight issue is no longer a problem. Furthermore, Bluetooth can synchronize and exchange data between devices, talk to printers, and receive signals from keyboards, mice, and other devices, automatically adding devices to and removing them from the system as needed.
In contrast, setting up a network of devices connected by cables is a complex business. The devices need to be intelligent enough to handle the overhead required as part of a network and therefore larger (in software terms, at any rate) and more complex. (Think of overhead as the difference between a freelancer and an in-house writer: a freelancer simply picks up the phone to talk to a contact, whereas an in-house writer needs to arrange a meeting room, time, and place, prepare an agenda, etc.) Each device on the network requires an address (or the use of a master address donor). And don’t forget all those cables and hubs and routers. A well-designed wireless network can relieve you of at least some of these problems.
Basing Your Network on Wireless
Wired networks are pretty fast. Compared with infrared, which operates at 120,000 bits/second, the slowest Ethernet network operates at 10,000,000 (10-Base), and 100-Base, ten times faster, is now the norm. By comparison, the slowest wireless networking standard (and currently the most common), 802.11b, transmits data at just over 11 Mbps. That’s faster than 10-Base Ethernet and marginally slower than the theoretical speed of the fastest asynchronous digital subscriber line (ADSL) now available in Japan.
To implement wireless networking, you need a wireless transceiver in your computer (usually a card but sometimes a USB device) and a wireless hub or “base station.” The base station connects wirelessly to the “hosts” (computers, printers, etc.) and by cable to a conventional wired local area network (LAN) or the Internet. In other words, the high-frequency radio waves between the hosts and the base station take the place of Ethernet cables. Anything you normally do using Ethernet over a LAN, such as connecting to the Internet, sharing files, or printing, can be done over the wireless network.
What makes wireless networking particularly useful is that devices connect to and disconnect from the network as needed. For example, I started writing this article at home, continued writing it on the train, and am now at home again. In that time, I’ve successfully disconnected from and reconnected to my home network, all without touching a single cable and without rebooting or reconfiguring my computer.
For a computer to join and leave the network as needed, its operating system must support this functionality. Currently, Mac OS X v. 10.2 and Windows XP are the leaders. AirPort (known as AirMac in Japan for copyright reasons) is Apple’s implementation of the 802.11b wireless standard, which is also known as Wi-Fi, from “wireless fidelity.” Although it did not invent the standard, Apple was responsible for making it accessible to the world. Wi-Fi is not only used for home networks but also used at coffee shops, fast food restaurants, and other public areas in Tokyo and other major Japanese cities to provide free or fee-based public wireless Internet access.
What are the disadvantages of wireless networking? It runs down the batteries on your laptop computer. All those radio waves coming into and going out of your computer consume power. Wireless networking operates at a range of about fifty meters. My local park seems to be fifty-one meters from my base station, which means I can’t sit in the park and work on sunny days, as much as I’d like to. Health hazards from the radio waves? I don’t like to think about that while resting a wireless-connected laptop computer on my lap.
Security is another concern. A good base station will prevent other computers from using it except those you explicitly specify. (All wireless adapters have a number “burned into” the hardware that can’t be changed.) You can also use passwords to restrict access to the base station. These measures stop others from using your Internet connection for free and from accessing the data on your network in the event you have left passwords unset and doors for snoopers to walk through on your computers. Most good base stations also support encryption, which prevents eavesdroppers from outside the network from looking over your shoulder electronically. Although encryption will deter 99% of casual snoopers, it is not unbreakable, so if you’re involved in rocket science or work for a three-letter agency, I suggest that you do not use wireless networking. If you do “go wireless,” make sure you read about and implement the security features of your base station. I have successfully logged into several wireless networks around Tokyo that were not meant to be open but turned out to be freely available to the nearest taker. One of my neighbors regularly turns on his or her base station, allowing me to use that network. I’ve tried to warn the owner but have not yet discovered his or her identity.
Looking Ahead
The 802.11b standard provides reasonable networking speed, but as anyone who works with large files and has made the leap from (wired) 10-Base to 100-Base Ethernet knows, you can never have enough bits per second traveling between computers. The 802.11a wireless standard provides up to five times the speed of 802.11b but at a cost: it’s incompatible with 802.11b networks, which are widely used. Enter 802.11g. (Extensions c, d, e, and f aren’t relevant to this discussion.) Recently introduced by Apple as AirPort Extreme (AirMac Extreme in Japan), 802.11g provides five times the speed of older networks and greater compatibility with them. The range is about the same as before with 802.11b.
The ideal situation for technophiles is the ability to log on to the Internet at broadband speed from anywhere. We have a little way to go before that happens, but in the meantime, you may want to check out the cellular and PHS modems (another form of wireless) allowing access from a wider variety of places, although at a slower speed. I use an NTT DoCoMo PHS modem that allows me to log on and check my email within a minute. Since this service is priced on a per-minute basis, it’s not suitable for extended surfing, but it’s fine for a quick mail check. Other cellular carriers provide similar hardware, and a variety of cables and related hardware is available to enable your laptop or other portable device to access the Internet through your mobile phone.
What’s next? Now that hardware components have been standardized, more software embedded in the networking equipment itself to make wireless networks easier to set up and maintain is on the horizon. At present, although computer manufacturers have produced wireless networking equipment that doesn’t require expert help to use successfully, it’s not as easy to set up and use as, say, a CD player. Apple is currently leading with self-configuring networks, and Microsoft is pursuing a rival standard that also holds great promise. But even with today’s software, for anyone who has successfully set up a home LAN, a simple wireless network is easy enough to install and provides freedom from the tyranny of spaghetti-like cables.