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WLAN growing up -and growing out

When the first wireless LANs appeared on the scene, no one expected the uptake would be so fast and furious. As the mobile workforce takes hold and more and more of the population expects anytime, anywhere connectivity, WLAN boundaries are constantly being pushed beyond their intended limits to accommodate their needs.


September 1, 2008  


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Andrew Mitchell, regional manager of Wireless Solutions for Bell Canada in Toronto recalls that when the first WLAN was deployed at Union Station in the city’s downtown core, “We all wondered if it would take off. Obviously it has proven itself to be an invaluable asset to enterprises, small businesses and consumers. Now it is a utility that can support anything from commercial and manufacturing functions to retail POS (point of sale) applications.”

This steep adoption curve has been largely driven by the fact that equipment has proved itself to be remarkably easy to deploy and use, and the costs keep going down.

Over time, bandwidth, availability and security have also continued to improve to support more robust applications.

“There are a couple of characteristics of WLANs that have been important drivers of their success,” Dragan Narandzic, CTO of Ericsson Canada in Toronto confirms. “First, they use open standards that are globally accepted. Secondly, they utilize unlicensed spectrum, which puts the end user in full control of both the equipment and spectrum use.”

These factors have allowed free wireless access and connectivity that is not dependent on operators or licenses. As a result, the entry barriers for establishing networks are very low and equipment production has now achieved very large economies of scale.

Given the relative economies associated with WLAN deployment, it comes as no surprise that more creative-minded network specialists are keen to push WLANs further to deliver continuous coverage over progressively larger geographical areas.

Recent projects in the works range from campus-level wireless networks (see sidebar) to the establishment of municipal wireless LANs.

Mesh has become an increasingly popular approach for backhauling traffic from one WLAN access point to another using the same signal. “The attractiveness of mesh relates to the fact that it’s an easy-to-deploy blanket solution for larger coverage areas,” Mitchell says. “If you are looking at an outdoor venue for example, the challenge of running cabling or fibre to access points disappears when you go with mesh.”

However, access point density and distance can create problems in some scenarios depending on the geographical area and bandwidth requirements.

Narandzic notes that where metro area networks have been attempted, many have yet to achieve ubiquitous coverage. “You need a very large number of nodes to establish that level of coverage, so it would simply be too cost prohibitive. Some U. S. and international cities that have deployed WLAN in metro area networks also found they had to deal with different types of complexities, including interference, signal strength and the inability of equipment to stand up to weather conditions.”

Meshing in Moncton

The IT department for the City of Moncton & Magnetic Hill were among the first to overcome the limitations for metropolitan area networks when they unveiled its community-wide WLAN initiative last year.

Director of Information Systems Dan Babineau reports that when it first deployed WLAN five years ago, the city’s focus was on enabling connectivity in its corporate buildings for employees and visitors.

“Having done that, we saw a greater need to extend outside the perimeters of the standard facilities to bring anywhere/anytime access to the people of Moncton and visitors. So we started with the brick and mortar part, and then decided to go outside the walls using Cisco wireless mesh technology.”

The downtown core pilot project has already grown to a one kilometer radius, with plans to triple that by the end of the fall season.

An important aspect of the mesh configuration is that it has allowed the municipality to keep the landscape — and the heritage buildings — intact.

The network uses an 802.11a radio system to transmit signals from the access points back to city hall where they connect to the Internet. “One big issue we had was around cabling and infrastructure costs,” Babineau says. “This approach helped us to streamline cabling and keep those costs down.”

Four Cisco controllers located at city hall are used to identify each access point on the mesh, record their location, monitor traffic and determine the best communications path back to city hall. The controllers also detect if an access point is down and intelligently reroute the signal, as well as looks for rogue access points and security violations.

Babineau adds that the biggest surprise in establishing the expanded WLAN services was the speed of deployment. “We simply identified the poles we wanted to use, mounted the equipment, plugged it in and turned it on. Within three days of starting work, we had it up and running. We were told it was quick and efficient but we didn’t quite believe it. We do now.”

The ability to stretch WLAN beyond building boundaries has been facilitated to a large extent by the evolution of standards, says Narandzic. “Many enhancements in the 802.11 standard have increased throughput and modulation schemes, which in turn have increased the potential size and reach of WLANs.”

With the added speed and performance of the latest standards however, comes the usual challenges when it comes to testing says Ron Groulx, product manager, Fluke Networks Canada in Mississauga.

“One of the biggest WLAN issues for the cabling industry right now is the emerging 802.11n standard,” he says. “That’s definitely a challenge for testing because it uses multiple streams for transmission that fundamentally represents a new approach for access point signaling. It makes it hard to know how to test it and understand where the bottlenecks take place.”

In addition to standards issues, Groulx notes that an equally significant challenge for WLAN deployment is security. “With the first wireless implementations about five years ago, security was very weak. Although encryption and security techniques have evolved considerably since those early days, the problem we are seeing now is that there are so many implementations of these (security) techniques. IT departments are struggling with understanding multiple encryption types and confused over what to use…or not.”

Another challenge is getting an understanding of how to marry internal security processes with wireless applications. “It’s difficult to know how to manage it all and take advantage of the right technologies,” Groulx says. “A lot of IT engineers think they are fully secured but not taking advantage of everything they could.”

One way to ensure a clear path to WLAN success is putting in the work upfront, advises Mitchell. “Anyone looking to WLAN deployment should never overlook the importance of robust design. It’s important to make sure you undertake a site survey and spectrum analysis so you don’t end up spending money later on mitigating problems and trying to get your network to perform at the expected bandwidth levels.”

The future is friendly: Despite the challenges, WLAN remains a “full steam ahead” proposition for the foreseeable future. As networking specialists continue to test WLAN boundaries, there is now talk of using Wi-Max (Worldwide Interoperability for Microwave Access) to push wireless access that extra distance.

Babineau says Moncton did look at Wi-Max at the outset of the project but wasn’t convinced of the need at the time. Next year all that will change. “Now we’ve built Wi-Max into the plan for backhaul because it’s more forgiving in terms of line of sight. This is very compelling for us since we have to deal with a lot of trees and infrastructure issues that pose a challenge to mesh and limit our growth.”

Wi-Max will definitely play a role in supporting WLAN deployments in the months to come as far as Sai Subramanian, director of marketing for Broadband Wireless Business Unit for Cisco Systems in Dallas, Tex. is concerned. “Wi-Max will do for broadband what cellular phones did for voice. It will deliver the same freedom to end users that
have come to expect WLAN access at home, work or on campus. It has the potential to take wireless access to a larger scale. Over the next two to three years, I expect to see Wi-Max embedded in the same way Wi-Fi is today.”

Subramanian also believes the Wi-Max could be a significant revenue generator for cabling professionals looking to enter the wireless market space.

“By bundling cable as your broadband wired piece with Wi-Max as your wireless service, you can give customers broadband at or outside their homes/offices. Because Wi-Fi has been so popular and so successful in enterprise and home setting, we need to do the same in a wide area setting.”

An added bonus he adds is that for the most part, mesh and Wi-Max can easily operate in tandem.

“Wi-Max would never be used in a building. By the same token, you can’t use Wi-Fi to cover all of the country. Leaving those two extremes aside, they will meld to each other very well. In either case both have big role to play in delivering wireless broadband in the future.”

Denise Deveau is a Toronto-based freelance writer. She can be reached at denise@denised.com.