Wi-Fi wireless networking has been a great success over the past two years. Intel has even been advertising the unwired life on prime-time television: wireless networking is included in its Centrino chip set. But no technology is without problems, and Wi-Fi has a couple that could trap the unwary.
The Wi-Fi logo is supported by the Wireless Ethernet Compatibility Alliance, and can be applied to wireless local area networking products that pass its interoperability tests. The underlying standard is IEEE 802.11b.
As usual, there are other versions of the standard designed to offer even faster wireless connections. The leading contenders are 802.11a and 802.11g. Both offer a nominal speed of 54 megabits per second, which compares with 11Mbps for 802.11b.
Surprisingly, since this standard has not been ratified, you can already buy 802.11g equipment. I wonder how many of the people who have been rash enough to buy unratified products have also been circumspect enough to get a money-back guarantee if they turn out not to be compatible with the final specification.
The attraction of 802.11g is that it operates at the same frequency as 802.11b. This should mean that 11g products will be able to talk to 11b products. And the whole history of the data processing industry, from Herman Hollerith's 80-column punched cards to the 80-character screens still in common use today, suggests that backwards compatibility is essential.
However, 802.11g is also a compromise with major drawbacks. It actually has to support two wireless systems: the old one from 802.11b and, ironically, the new one from 802.11a. Unfortunately, the 802.11g implementation of the 802.11a system is crippled.
Why is 802.11a - which we can now call Wi-Fi5 - better than 802.11g? First, it uses the 5GHz wireless frequency range. This means it does not suffer from interference from Bluetooth wireless, cordless phones, microwave ovens, and all the other rubbish that uses the same unlicensed 2.4GHz frequency as 802.11b and 802.11g. Second, Wi-Fi5 supports eight simultaneous communications channels instead of three and 2.4GHz simply does not have enough capacity to support eight channels.
As for the incompatibility of 802.11a and 802.11b, you can solve that by installing separate hubs (or wireless access points) for each system. Alternatively there are "bridging" 802.11a/b hubs, such as the Cisco Aironet 1200 series, and dual mode notebook cards such as D-Link's AirPro DWL-AB650.
We've already seen a hint of problems with 802.11b at the recent CeBIT computer trade show in Germany. So many companies were trying to run separate Wi-Fi networks side by side that everybody's throughput approached zero. Things could get a lot worse , as Wi-Fi becomes more popular, and as more and more radio gadgets pile in using the same bandwidth.
It could be better to go for 5GHz and 802.11a now, when it will hurt a bit, rather than later, when it might hurt a lot.
