Public wireless Ethernets, offering speeds comparable to typical office networks for prices usually around $8 to $10 a day, are cropping up in airports, hotel public areas, coffee shops, and other "hot spots" around the country. Companies such as Wayport and VoiceStream Wireless' T-Mobile (formerly Mobilestar) have offered such services for a couple of years. But several factors are making them more available and easier to use ("All Net, All the Time," Special Report, Apr. 29).
The most obvious factor is that the popularity of wireless networks using the same Wi-Fi technology in offices, campuses, and even homes means that far more laptops are equipped with the proper adapters. In fact, many laptops now come with Wi-Fi (also known as IEEE 802.11b) transceivers built in. Or you can add a Wi-Fi PC card, which starts at about $80.
Microsoft has made Wi-Fi use much easier by building good support for it into Windows XP. When you click on the system tray icon of your Wi-Fi adapter, a menu offers to show you any available network. You click on your choice of network, enter a password if needed, and you're on the Internet. Sometimes you can just take advantage of a network in the neighborhood that has been left open for access by anyone.
Finally, tiny islands of wireless availability are combining into much larger areas of wireless coverage. In the past, an account with Wayport did you no good in an American Airlines Admirals' Club, where the service came from T-Mobile. But aggregators such as Boingo Wireless, iPass, and Gric Communications are striking deals to let them offer a single account that provides access to many networks.
Boingo, for example, offers three service levels: A one-day sign-in for $7.95, 10 connect days a month for $24.95, or unlimited monthly service for $74.95. This gives you access to the networks of Boingo partners, from major providers such as Wayport to little independents (but not at the hundreds of Starbucks shops with T-Mobile service; so far, VoiceStream is going it alone). Boingo's software lets you "sniff" available networks on any version of Windows, but the current version requires turning off XP's built-in Wi-Fi support.
Wonderful as public Wi-Fi is, it still only solves part of the mobile data problem. Availability will probably always be limited to hot spots rather than the wide areas covered by the data services of wireless-phone carriers. Wi-Fi technology is cheap and simple, but only three channels are available in any location. If too many networks are set up too close together, they can knock each other off the air. Since the 2.4 gigahertz spectrum they use is unregulated, there's no good way to resolve conflicts. This situation will improve somewhat with a migration, starting later this year, to a faster 5 GHz standard called 802.11a, which offers 11 channels.
Wi-Fi allows only limited mobility. Unlike cellular networks, Wi-Fi does not provide seamless transfer from one base station to another as you move. This is not much of a problem for laptops, which usually stay in one place while being used, but is a serious limitation for pocket PCs and other handhelds.
Wi-Fi is also inherently insecure. Experiments have shown that even the "strong" 128-bit encryption is easily defeated. Mobile executives should use their companies' virtual private networks (VPN) to encrypt data exchanged with corporate servers. Otherwise, avoid sending sensitive information over a Wi-Fi network.
Despite the limitations, Wi-Fi has tremendous potential to make mobile life easier. Some day, third-generation wireless phone networks may make high-speed data services available everywhere. But that's years away, and Wi-Fi is here today and growing fast. By Stephen H. Wildstrom