Originally created 09/15/03

The ABCs of Wi-Fi



Q: I'm thinking about getting a wireless card for my laptop, but I'm a bit confused about the different kinds. What's the difference between 802.11a, 802.11b, or 802.11g?

A: Wi-Fi, the technology that creates "hotspots" where computers can connect wirelessly to the Internet, is a big hit, but buying into it has become a bit more difficult.

There are now several different flavors of Wi-Fi, unfortunately only told apart by the letters that describe the technical standards.

The original Wi-Fi technology is 802.11b, now widely deployed at universities, Starbucks stores and techie homes. The equipment for "b" is the cheapest, with a laptop card costing maybe $50. Most of the laptops that come with built-in Wi-Fi use "b."

However, I would recommend spending another $20 or so to get a card that does 802.11g, the up-and-coming standard. (Some manufacturers are trying to give it less geeky names. Apple calls it AirPort Extreme; Linksys calls it Wireless-G.)

802.11g is about four times as fast as "b," and connects to the older hotspots, albeit at the slower speed.

You may not see much of an advantage from a "g" card at first, since most hotspots still use "b." Also, the speed of wireless Web surfing is usually not limited by the wireless connection, but by the speed of the connection between the hotspot's base station and the Internet.

But 802.11g looks set to become the new standard. Equipment for it has sold strongly since it was introduced earlier this year, and analyst Greg Collins at Dell'Oro Group, which tracks sales of networking equipment, sees it surpassing 802.11b in consumer sales by the end of the year.

You'll want to stay away from cards that only do 802.11a. They won't connect to "b" or "g" hotspots. 802.11a is an older technology that is as fast as "g," but it hasn't caught on widely since it doesn't work with "b."

There are more expensive cards that do both "b," "g" and "a," which can be useful if your hotspot does "a." Dell'Oro said multimode devices were about 3 percent of Wi-Fi sales in the second quarter.

The advantages of 802.11a are that it can support more users and is not susceptible to interference from 2.4 gigahertz cordless phones, which can make hotspots using the other standards unusable. 802.11a uses the less crowded 5-gigahertz band.

Another letter is set to drop into the Wi-Fi alphabet soup late this year or early next year. 802.11i will be a new standard aimed at making the wireless network more secure from eavesdropping and unwelcome guests.

Many corporations have delayed deploying Wi-Fi because of its well-publicized security flaws - it's not too hard for a hacker to access a poorly set-up company wireless network from outside the building, for instance.

802.11i aims to remedy that with encryption technology. The bad news is that it will most likely require new equipment. If you're really concerned about security, you may want to wait for that.

On the Net:

http://www.wi-fi.org

http://www.hotspotlist.com