How fast are wireless LANs?
Wireless LAN specs suggest much faster rates than can ever be achieved in the real world
If you bought a new car that ran at less than half the advertised top speed you'd take the manufacturer to task. Likewise you'd complain if it took twice as long as promised to fly to your holiday destination.
But when it comes to wireless networking it seems we're happy to swallow whatever performance figures manufacturers feed us, no matter how far from the truth they turn out to be.
The distance between hype and reality is, in fact, quite disturbing, as highlighted by our various lab tests of wireless products undertaken over the past two years. In those tests, current 802.11b products, for example, struggled to deliver more than 5Mbit/s even though some vendors claim throughput rates of up to 22Mbit/s. Similarly, with the latest 802.11a and 802.11g solutions the results show actual rates failing to top 20Mbit/s despite claims of up to 54Mbit/s in both cases.
For home users wanting to connect a couple of PCs and share a broadband internet connection, this lack of speed is unlikely to be a problem. After all, most home broadband links deliver a lot less bandwidth than even the slowest wireless technologies. However, if you rely on your network for business, and have opted for wireless rather than wired technology, you will be very disappointed.
On a switched wired network, for example, you can confidently expect close to 100Mbit/s of bandwidth per user. Splash out on Gigabit Ethernet and you can get a lot more but, even without it, taking a backup of a 1GB Outlook personal storage file would take around 80 seconds on most fixed LANs. According to the results obtained in tests, on the top-performing Cisco 802.11a wireless network, the same transfer would take five times as long, or nearly seven minutes.
And there is another complicating factor, usually only mentioned in the small print, concerning what happens when upgrading to high-speed 802.11g wireless technology, which uses the same waveband as current 802.11b hardware.
The bad news is that if you mix the two together, throughput drops like a stone. Down, in the worst case, to the level of the slowest technology, so that a 1GB data file would then take nearly half an hour to copy.
And there are other things that manufacturers exaggerate or gloss over, such as range and the effect of interference. As wireless networking proliferates interference is becoming an ever greater problem.
Convenience is the big advantage of wireless networking and key to its popularity. But that shouldn't blind us to the realities of the technologies involved. The old saying "buyer beware" applies, making it important for any business to do its homework before ditching wired infrastructure.