Networking

What CIOs should know about wireless networks before choosing a solution

Wireless got you worried? Here are a few issues to consider before committing to a wireless networking solution.

It’s relatively simple to install a wireless LAN, according to Yuval Goren. So easy, in fact, he uses a wireless network both at the office and at home.

But then again, Goren is the vice president of product engineering for BreezeCOM, a major wireless equipment vendor whose core technologies include spread spectrum radio, digital signal processing, modems, and networking protocols.

Goren contends that wireless LANs are simple and, compared to wired LANs, economical to install. Often, an organization’s own MIS team can handle the task without any extra support—depending on the size of the office.

When wireless makes sense
Goren identified two reasons to choose wireless: cost and simplicity. While it might take you months to wire a building and lay cable to connect multiple locations, you can install a wireless network between buildings in an afternoon.

“It’s going to be much cheaper than any wired technology,” Goren said. “It is really a plug-and-play solution.”

For example, BreezeCOM leases a second building, roughly 1,000 feet away from its main office, on a month-to-month basis. The company wanted the building networked. However, since the company isn’t sure how long it will lease the space, it did not want to pay the cost of laying cables and installing a wired network. So they chose to install a wireless network and connect it to the wired network in the main office building.

“I can take my computer and go anywhere in those two buildings and between those two buildings, and I am connected all the time,” Goren said.

BreezeCOM’s wireless network also encompasses a nearby hotel, so guests can be logged in to the network from their rooms. Goren said that if you place an antenna on a main building, a wireless network also can provide access for remote users and mobile workers, provided these users have a line of sight to the building and are less than ten miles away.

Vobix CEO and TechRepublic columnist Tim Landgrave used wireless to resolve a similar problem. When the application service provider company first formed, it leased temporary space.

“We ended up having to be at three different locations in this park, and we could literally put an antennae in each window and all be connected to the same network. Whereas if we had been wired…you can’t take a wire and run it across the parking lot to the building next door,” Landgrave said. “It’s all logistics problems.”

The point isn’t to make wireless omnipresent. Instead, organizations should use it when it makes sense, Goren said.

“The idea for the office is not to replace the wired connection by a wireless connection for everybody. Many people are stationary. They sit in their cubicles all day; they don’t need the mobility,” he said. “It’s typically a combination. People don’t go all wireless or all wired, but use a combination of both, based on their needs.”

Sometimes, companies use wireless when what they really need is a wired network, explained Jim Geier, an independent wireless consultant and author of Wireless LANs.

“I've seen some companies implement wireless networks for applications where a wired solution made more sense,” he said. “If application requirements support the need for a wireless network, a company should assess the many technologies and choose the one that best satisfies requirements and constraints.”

Frequency hopping versus direct sequence
There is primarily one standard for wireless LANs and WANs: IEEE 802.11, the standard produced by the Institute of Electrical and Electronics Engineers (IEEE).

IEEE 802.11 equipment uses unlicensed radio frequencies of 2.4 or, in rare cases, 5.7 Gigahertz. This is different from broadband wireless, which uses frequencies that require an FCC license.

Most equipment today conforms to the IEEE standard. There are two choices for creating a wireless network:
  • Frequency hopping
  • Direct sequence
You may have heard a lot about broadband wireless Internet and Bluetooth technology, but these really aren’t applicable for a wireless LAN. Bluetooth, for instance, is limited to a relay distance of 30 feet, making it more appropriate for a personal network. And broadband is more of a backbone technology, the equivalent of cable Internet or ADSL.
Frequency hopping and direct sequence are types of spread spectrum radio area frequencies. According to the Wireless LAN Association, spread spectrum is “a wideband radio frequency technique developed by the military for use in reliable, secure, mission-critical communication systems.” It’s designed to trade bandwidth efficiency for reliability, security, and integrity.

Frequency hopping and direct sequence are not interchangeable, and each has different uses. “Frequency hopping is known to be much more immune to interference,” Goren said.

This doesn’t just mean interference from the outside, like cell phones and radio signals, he explained. When there are numerous users in a small area, the system is less likely to experience interference between users on a frequency hopping system than with a direct sequence system. Typically, frequency hopping systems can support more users. Frequency hopping is also a better option over a wider area.

But direct sequence does offer a higher performance—up to 5 megabits per second. “Direct sequence is really good when you have a small number of users and you can put a few cells—let’s say up to three—access points to cover a specific building,” Goren said.

Security
Landgrave said it is technically possible for him to connect to the Vobix network outside the company’s office. But that’s a mixed blessing.

“I could pull up to the outside of my building, open my laptop and turn it on, and be on the network. This is great for me because I happen to be using encryption keys,” he said. “But if someone doesn’t have encryption keys turned on, I could technically pull up outside their building, set it to any network, get a DHCP address, and start hacking their network.”

Because of this possible security issue, Landgrave suggested that businesses considering a wireless LAN should decide how to secure that network.

But Goren said wireless networks are no less secure than wired networks, which, he pointed out, radiate signals. In fact, he contends, wireless may be more secure. For instance, with frequency hopping technology, you change frequencies every 100 milliseconds. If you don’t know the frequency being used, you can’t intercept the information, he said. According to the Wireless LAN Association, spread spectrum appears as noise to unintended receivers.

Support, user needs, and scalability
Choosing a wireless LAN or WAN solution requires you to evaluate your specific business needs and to consider the following issues:
  • Non-PCs: Will the system support non-PC devices, such as PDAs?
  • Bandwidth: What are the bandwidth needs of users? Wireless LANs carry about 2 to 3 megabits per second, which is enough for most users, but you may need to have fewer users per access point if you have high-bandwidth needs.
  • Radio frequencies:Geier suggests your company perform a radio frequency site survey to determine the effects of radio frequency propagation in your office before purchasing solutions. (See Geier’s Web site for his column “Avoiding wireless woes: Survey your site.”)
  • Roaming:While cell phone conversations can lose a quarter of a second without a problem, a network could lose packets in that time. It’s important that the system switch from access point to access point without compromising data.
  • Load balancing:“You want the system to balance itself so you will have the maximum performance per user,” Goran said. “So if you have five access points and 50 users, you want it to balance so you get 10 users per access point.”
  • Vendor support:“If you have a problem, will you have somebody to call?” Goran asked. “What kind of response will you get? Will they send someone to help you if you have a major issue?”
  • Scalability:Goran advised finding a system that can grow along with a company.
We’re curious: Will you go wireless? E-mail us and let us know if your company is ready for a wireless LAN.
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