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No Strings Attached

Wireless Technology Has Gained Great Momentum -- Not to Mention Capability -- Over the Past Few Years. Does This Mean War Against Its Traditional Hard-Wired Counterpart? or Will the Two Technologies Find a Peaceful Way to Co-Exist?


January 1, 2000  


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At a Royal Bank of Canada office in Toronto that helps commercialize Canadian research and development, staff who work with startup companies are constantly on the move. People switch “on a fairly dynamic project basis from one project to another,” explains Charles Houen, a senior consultant with responsibility for the unit’s networks. So the bank needs an easy way to handle moves, adds and changes without costly and time-consuming rewiring.

Northern Alberta is a long way from downtown Toronto. And the problem facing the Northern Lights School Division is rather different from the one confronting the Royal Bank. The sprawling school division covers more than 5,000 square miles in northeastern Alberta, and its challenge is to connect all of its schools and maintenance facilities.

Yet, while these two problems are quite different, both the Royal Bank and the Northern Lights School Division have turned to the same solution: wireless networking.

The Royal Bank’s need for flexible, easily updated networking on one floor of a Toronto office building led them to install two WaveLAN wireless local-area networks (LANs). Supplied by Lucent Technologies Inc., the WaveLAN system covers about 12,000 square feet and moves data at up to 11 Megabits per second (Mb/s).

The bank has implemented one network for its own employees and another for employees of an early-stage seed capital company that shares the space and is partially owned by the bank. The two networks operate in the same physical space without interference, Houen notes.

The Northern Lights School Division chose a Hopper Plus wireless system from Wi-LAN Inc. of Calgary. The Hopper Plus system is limited to two Mb/s but can operate over long distances. Gary Krawchuk, Secretary-Treasurer of the school district, says Northern Lights’ longest single link reaches about 30 kilometres.

Each company turned to different wireless products designed to suit their particular needs, but their experiences serve to illustrate that wireless is a versatile way of solving several kinds of networking challenges.

Wireless Comes of Age

Wireless networks are not new, but they have taken some time to come of age. In the past couple of years, the completion of an international standard known as IEEE 802.11 has brought the promise that wireless products from different manufacturers will soon be able to interoperate, and the speed of wireless LANs has begun to compete with that of commonly used wired technology.

Until recently, wireless network speeds topped out at about two Mb/s — just one fifth of standard Ethernet’s 10 megabits. However, the 802.11b standard, an extension of 802.11, can support 11 Mb/s. The first wireless network products actually delivering that speed have started to hit the market.

The availability of wireless LAN products that can compete on speed with the most commonly used hard-wired networks, coupled with trends such as telecommuting and “hotelling” — in which several employees who spend much of their time outside the office share a desk when they are there — will greatly increase the use of wireless data networks, says John Williams, Program Manager for WaveLAN products at Lucent’s Canadian office in Toronto.

Voice transmission is a different matter, at least for now. While wireless telephony is becoming ubiquitous outside the office — the cost of cellular telephones and services has become very affordable and the services have become more useful with the arrival of widespread roaming and better coverage — wireless telephones have yet to catch on within the walls of most offices.

Williams, whose company makes both data and voice communications equipment, says wireless phone systems are not likely to offer all of the capabilities of hard-wired systems any time in the foreseeable future. Since most organizations have existing phone wiring, there is less incentive to consider wireless as an alternative for voice transmission. The exceptions are workplaces where mobility within the workplace is vital. With a wireless telephone a doctor can move around a hospital and still be easy to reach, or a busy manager can go from office to conference room to manufacturing floor without being out of range of the phone.

Combining Voice and Data

The long-range promise, of course, is voice and data together on the same wireless network. Combining voice and data over the same wires is a hot topic these days, and the same voice over Internet Protocol (IP) technology could eventually let wireless data networks carry voice as well, says Nick Tidd, President of 3Com Canada Inc. in Toronto. This will appear first in small work groups and clusters.

However, Williams says, it is not quite there yet. IP needs quality of service capabilities to ensure good voice transmission, and these are not readily available in the wireless world today, he says. Tidd says policy-based network management will eventually be able to allocate bandwidth as needed to make voice and data work smoothly over the same wireless network.

Both data and voice communication can take place within an office, over short distances between facilities or over the long haul. Today, wireless voice is most popular for the long haul — in the form of cellular telephone systems — and less so over short distances. Wireless data is the opposite. It is primarily used within buildings and between two or more buildings that are fairly close together.

The arguments for wireless technology are different in each of these cases.

Wireless within a single building is attractive where no suitable wiring already exists and installing it would be a problem for one reason or another, or where frequent moves, adds and changes will be much easier with wireless technology.

“We have the flexibility of reorganizing your organization almost at a whim,” says Williams. If employees move from work group to work group, “they can just move the computers over, plug back in, and the network is established immediately.”

If your workplace does not require that kind of flexibility — and installing cabling is not especially difficult, as it would be for instance in a stone-walled historic building — then wireless probably is not the answer, Williams says. “If the desktop is not going to move for two or three years, it’s more cost-effective to hard-wire.”

Moving employees and computers within the office is not the only kind of potential move that might justify choosing wireless, though. If you move the whole operation to a new location in a couple of years, any new wiring you install will be left behind. When such a move is likely, a wireless network may be more attractive because you can take your investment with you.

When the problem is to connect two or more buildings over a moderate distance, the main alternative to a wireless link is a public carrier. There may be cases where an organization can string its own wires to link neighbouring buildings, but those are rare, says Pierre Deschenes, President of Microroute Inc. in La Prairie, PQ. The usual way is to lease capacity from a carrier. “If you try to go with Bell it’s going to cost you lots of money for a small bandwidth,” says Deschenes, who points out that the two-megabit capacity of a wireless link looks good next to a single T1 line, which carries 1.54 megabits per second. Such a line costs $1,000 to $1,500 per month, he adds, and the equipment at either end is another cost on top of that.

Addressing Concerns

Wireless LANs are now beginning to offer enough speed to serve the average desktop computer quite well. Houen at the Royal Bank says that when his business unit put in its WaveLAN network, some employees thought the new system was actually faster than the 16-Mb/s Token Ring network they were using before. In reality the new wireless network was quite a bit slower, since the cards the bank put in at first were two-megabit cards — but as each workstation had its own wireless link to the hub, rather than sharing the 16-megabit capacity of a ring, performance actually looked better.

Other concerns about wireless networks in
clude interference and security. One of the greatest fears about wireless transmission is that a neighbouring wireless network might either pick up your sensitive data and put it in the wrong hands, or cause transmission errors on your own network. Other factors, such as electrical currents, certain kinds of obstructions, or in the case of outdoor connections, weather conditions, may also cause interference.

Today’s wireless networks use two main tricks to address these concerns. First, they support multiple channels so that if there is an interference problem on one channel, the network administrator can simply switch to another. Houen’s installation at the Royal Bank is a good test case; two separate WaveLAN networks serve different groups of users in the same physical space, and he says there are no interference problems.

Jason Hill, President of Total Network Solutions, London, ON, says there are no guarantees when installing wireless links between buildings. “Someone else can put one up next door and interfere with your signal and effectively bring you down.” However, he says, the selection of channels that many systems provide generally offers a way out.

From a security point of view, the second line of defence is encryption, which ensures that even if a neighbour’s network picks up your data, unauthorized eyes will not be able to read it. Another trick that helps is frequency hopping. Richard Chown, Director of Business Development for Symbol Technologies Inc. in Kanata, ON, explains that networks that do this switch frequencies constantly, following a pattern so devices on the network can stay in touch, but making it much harder for an outsider to pick up the network traffic.

Weathering Storms

Outdoors, it is important to think about weather conditions. Hill, whose company specializes in building-to-building links, says “rain fade” needs to be taken into account when installing outdoor wireless links. Rain fade is more of a problem with infrared links than with 2.4-gigahertz wireless technology, he notes.

This does not mean wireless networks will shut down in bad weather, but it does mean an experienced installer will allow for the effect of weather on the signal, and this depends to some extent on the local climate. There are other factors affecting signal loss as well, including the choice of frequency and the curvature of the earth. The best way to avoid problems like this, Hill adds, is to turn to an experienced installer: “Far too often we see people trying to do it themselves and then blaming the technology.”

While most ordinary obstructions have little effect on the systems used for indoor transmission — a wireless LAN will work through an ordinary wall, for instance — outdoor transmissions are different. The general rule is that you need a line of sight between transceivers. Hill advises allowing some margin for error and for changes in the terrain when installing. For instance, a signal that barely skims the tops of trees today may be blocked in a couple of years as the trees grow taller.

A problem that is harder to prepare for is the construction of new buildings. “If you’re in a long-standing business park, chances are they’re not going to be putting up a high-rise next door,” Hill says — but businesses in areas just being developed may want to think carefully about this.

Backbones Staying Wired

There is one area where wireless data transmission cannot compete with wires, and that is the network backbone. With Fast Ethernet and even Gigabit Ethernet moving into the backbone, even 11-Mb/s wireless technology is left behind.

It seems likely that backbones will continue to rely on wires — or in a growing number of cases, optical fiber — while wireless links will be reserved for the desktop. Tidd adds that some workstations with high bandwidth requirements will probably always need wired connections as well.

Fortunately, according to Williams at Lucent, there are no significant problems in mixing wired and wireless technology in whatever way best meets your needs. So, while wireless networking has come a long way in the past few years, to the point where it is a good alternative to wires in many situations, do not hold your breath waiting for the network to be unplugged entirely.CS

Grant Buckler has written about information technology and telecommunications since 1980. He is now a freelance writer and editor living in Kingston, ON.

One of the greatest fears about wireless transmission is that a neighbouring wireless network might either pick up your sensitive data and put it in the wrong hands, or cause transmission errors on your own network.


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