Time For Your Office To Go Wireless?

Sep 10, 2002

Dan Orzech

Jim Geier wrote his master's thesis on wireless networks in the late 1980s, and has been working in the field ever since. The author of Wireless LANs and several other books on wireless networking, he is the founder and principal consultant of Wireless-Nets, a wireless networking consulting firm based in Dayton, Ohio. CIN spoke with Geier about the pros and cons of going wireless.

When does it make sense put in a wireless LAN?
Right now, wireless makes sense in two situations: if you want to support mobility, for something like point of sale or inventory bar code scanning, or if you're going into a new facility. If you have an existing facility that is already wired for ethernet and you're only going to be connecting PCs, there?s not much reason to go wireless.

Why does wireless make sense for new facilities?
The price of wireless equipment has been dropping steadily, and it's now to the point where it's approaching the cost of ethernet. Wireless products are still a little bit more expensive, but you can install them faster than you can a wired network, and you're going to have more flexibility down the road, so you won't have as many restructuring costs when you move people into new offices or remodel. If you have to tear down walls, you don't have to worry about cables.

Are there issues a CIO should be concerned about in putting in a wireless LAN?
Security is the probably the issue that tops the list for CIOs. The problem with wireless LANs is that they use radio waves, which makes them susceptible to someone eavesdropping on the network from outside your building.

Wireless networks do have security, for example you can encrypt traffic using Wired Equivalent Privacy, or WEP. But WEP it doesn?t work very well, it's crackable. People can download a utility from the Internet for free, and with the right technical background, they can crack it and get to your information, at least after a period of time. It may take them a while, and it takes someone fairly technically sophisticated to do it, but it's possible.

Within the next year, there should be upgrades to the 802.11 standard that addresses this problem, but in the meantime, it?s an issue to consider.

Does WEP add a performance hit?
In the past, it used to be done in software and it really slowed things down. Now it's done in hardware, so it's pretty much negligible.

Have hackers actually broken into wireless networks?
Some researchers at UC Berkeley have published papers where they described cracking a wireless LAN. But in practice, I don't know of any instances where a company was using WEP and someone broke in.

What has happened is that companies that don't use WEP have been hit. [Consumer electronics retailer] Best Buy was hit, but they were transmitting in the clear. Someone was parking outside Best Buy sniffing the packets being sent, figuring out account passwords, and getting credit card numbers. They were caught, but the lesson about using encryption is clear.

So how secure are wireless LANs?
In my opinion, the security problems with wireless are overblown. There are a lot of things you can do to make wireless just as secure as ethernet. There are proprietary security measures that you can deploy while we?re waiting for 802.11 to roll out the standardized version.

Such as?
There is a standard called 802.1X, which can provide mutual authentication between the user and an authentication server. 802.11 is considering incorporating that standard. There?s another standard called Advanced Encryption Standard (AES), which has recently been kind of blessed by the government. Many of these additional security technologies are included when you buy any equipment from any of the enterprise grade wireless vendors.

Are there other issues that should be considered besides security?
There's the question of interference, although in all the time I've been working with wireless, I've only seen one major case of interference with the radio waves. That was a company that discovered, after they had installed 300 wireless access points, that about half of them didn't work. It turned out that the ones that didn't work were all on one side of the building, which faced a river. Across the river was an air force base, whose equipment was completely blocking their transmission.

But that sort of situation seems to be the exception.
Right. Usually, interference will only cause the network to work a little slower, instead of completely blocking it. And to avoid the situation, I highly recommend that before installing a wireless network, you do an RF (Radio Frequency) site survey. That basically involves walking around your facility with radio frequency testing equipment to see what kind of interference you might have. Although of course, a week after you put your network in, someone could build a big radio tower outside your building and cause interference.

Are there other things you can do to minimize interference?
The 802.11 standard is gradually moving from a version called 802.11B to one called 802.11A. 802.11A operates in the five gigahertz frequency band, which is less susceptible to interference than the 2.4 gigahertz range that 802.11B uses. There are a lot of devices that can cause interference in the 2.4 gigahertz band, like microwave ovens and cordless phones. 802.11B avoids those, and it also has a higher data transmission rate.


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