continued

Once you have a laptop or personal digital assistant (PDA) set up to receive Wi-Fi transmissions, you can go to a free Wi-Fi location and ask your computer to show you the available networks. Some networks may ask you to register or log in. For instance, the Boston Public Library asks you to provide your name and library card number. But other networks are simply open to all comers without restrictions.

In some cases, you don't even have to go into the building. Before the Boston Public Library opened one Sunday morning, I found I could log into their wireless network from across the street. In New York City, Bryant Park is an outdoor Wi-Fi hot spot.

Setting up a Wi-Fi Network

Terminology for wireless local area networks (WLANs) revolves around the "802.11 specifications," standards established by the Institute of Electrical and Electronic Engineers (IEEE). There are three variants of this specification, 802.11a, 802.11b (Wi-Fi), and 802.11g which is typically also compatible with 802.11b.

Setting up your own Wi-Fi network is actually surprisingly simple. First you must have an Internet connection of some type (preferably broadband: cable modem, DSL, or T1), or, with Apple Airport base stations, simply a phone line. Then you need a "broadcast station" (a wireless gateway, or router) at that "access point" and a wireless adapter at each workstation.

The wireless access point (WAP) is the gateway, or the point where the hardwired network ends and the radio transmission starts. This is where your wireless router is plugged in, usually between your cable modem or DSL connection and the computer (which may be a server) that connects to it. The router's setup software uses that computer to configure the router so that it works with your Internet connection and/or network.

Most wireless routers come with optional firewall and encryption software, called wired equivalent privacy (WEP), that will give you an added level of security — and complexity — if you feel you need it. But whatever protections you install, we recommend that you always think of wireless communications as an "open line."

The job of the wireless router is to be a traffic cop between all the stations and the Internet connection (and/or the rest of the network) and to regulate between the sending and receiving between station and Internet and between stations.

Wireless adapters are used on all other computers to which you want to provide network access. These adapters come in three forms: expansion cards for desktop machines, PC cards for laptops — conveniently included in all current Apple laptop models — and also conveniently, USB jacks. USB jacks are small enough to fit on a keychain if you want to port your wireless connection from one computer to another. You can even get 802.11b flash cards to connect your PDA to the wireless network.

Because your router is like a radio station, it has a transmission range that radiates out in a circular pattern. The range varies according to the model you purchase. Just like with radios, transmission and reception may be affected by interference from microwave ovens, cordless phones, and even tinted windows, so experiment a bit on router location before you settle on a spot.

Security

The biggest conceptual drawback to wireless networking is a potential lack of security. A wireless network is like a radio station that anyone can tune into. To protect your network from outsiders using it, you should put up a firewall at your access point and activate an encryption protocol. This capability is built into the Apple Airport implementation, for instance.

Alternatively, if you are concerned about protecting your data but not about limiting access to your Internet connection, you can simply put up a firewall (like the excellent ZoneAlarm) at each station. Windows XP also provides an optional firewall program.

The security issue is also important when you are using free public Wi-Fi hot spots. Unlike with a cable connection, you are broadcasting your data through the airwaves which can be tuned into by a knowledgeable hacker with the right equipment. Therefore, I recommend not doing any financial transactions over a free Wi-Fi connection.

Wireless networking brings us tremendous new freedom in how we operate with our office networks and with our connections to the Internet. But, as with all new freedoms, it comes with new responsibilities and new dangers. Take a little extra care in setting up proper firewall protections and you will rest easy and enjoy immensely this new wireless environment.

Discuss this article in the Architecture Forum...

Evan H. Shu, FAIA is an architect with Shu Associates Inc. in Melrose, Massachusetts. He is a contributor to publications such as The Architect's Handbook of Professional Practice and Architectural Record and is publisher and editor of Cheap Tricks, a monthly newsletter for DataCAD users and computer-using architects.

This article was reprinted from the February 2004 issue of Cheap Tricks © Shu Associates Inc. with permission of the publisher.

All modern operating systems automatically detect and list available wireless networks. Image: Evan H. Shu, FAIA With a single click, users can switch from one wireless network to another. Image: ArchitectureWeek A wireless access point can be easily added to an existing hardwired ethernet network. Image: ArchitectureWeek Some third-party shareware and freeware programs provide additional information about wireless networks, including each network's security level. Image: ArchitectureWeek   Click on thumbnail images to view full-size pictures.