Networking

Wireless LAN in the Arctic: A cool solution

How do you wire a 25-year-old, concrete-and-steel building for Internet access by mine workers on an island far above the Arctic Circle? You don't! See how one network guru overcame physical limitations with wireless LAN technology.

One reason often cited for installing a wireless LAN is to overcome a challenging wiring situation, such as an old building or a physical location that would be difficult to cable. In this week’s From the Trenches, we’ll look at this kind of situation as we tag along with Claude, a systems coordinator faced with the task of providing Internet access for 50 to 100 workers in their residential quarters at a mining operation on an island north of the Arctic Circle.

We will see how Claude:
  • Justified implementing Internet access in the company’s residential quarters.
  • Set up a test network.
  • Constructed the working wireless LAN.
You can learn quite a bit by reading about the methods other administrators and engineers use to resolve challenging technology issues. Our hope is that this column will provide you with unique solutions and valuable techniques that can help you become a better IT professional. If you have an experience that would be a good candidate for a future From the Trenches column, please e-mail us. All administrators and their companies remain anonymous in this column so that no sensitive company or network information is revealed.
Taking it from the top
There are few workplaces more remote than the mining operation north of the Arctic Circle where Claude works as a systems coordinator. Communications and entertainment are costly and difficult in such a locale, yet they are critical elements of maintaining a successful operation.

Employees complained because Internet access on the corporate LAN was limited during working hours. After hours, employees could use a satellite telephone connection from their residential quarters, but that proved impractical because it had limited speeds of 4,800 baud and there is a 10- to 15-minute time limit.

Thus, Claude presented a business case to corporate officials to provide Internet access to employees in their living quarters as an extension of the frame relay network that connected the corporate LAN to the Internet. He presented the following benefits to management:
  • Increased productivity during the work day if employees weren’t surreptitiously surfing during working hours
  • Training opportunities via the Internet, which employees could use on their own time (Some employees, including Claude, are working on an MBA.)
  • Benefits associated with a morale boost

Once Claude won over management to the idea of Internet access in residential quarters, he was able to make a business case for a wireless LAN because wiring the residential building would have been very expensive. The building is 800 meters long (about 2,400 feet) and consists of four 3-story living areas separated by two-story common areas. The building is 20 to 25 years old and constructed of concrete and steel.

It would have been extremely expensive and impractical to wire all the rooms. The construction costs for such a project would have been phenomenal, and the project would have taken a lot of time to complete. “To wire this building normally would have cost thousands in hubs. I figured 16 hubs [at about $200 per hub] and switches and cabling costs,” Claude said. “The cost for wireless was $6,000 plus the wireless NIC cards and the cost to run four cables.”

He also ended up needing two inexpensive passive hubs to connect the wireless access points (APs) and to segment the wireless network from the business LAN. However, before Claude designed the topology of his wireless LAN, he engaged in some thorough testing to make sure wireless would be a viable solution.

Testing the wireless solution
Even though the cost of a wireless LAN looked appealing, Claude wasn’t sure if the wireless signals would make their way through the massive concrete-and-steel walls and steel fire doors that form the residential building.

“My major concerns in making it work were basically range—connectivity—and bandwidth. Would it be fast enough?” Claude said.

He contacted 3Com Canada Inc., and a representative there sent him a starter kit, which included a site survey tool. “I set it up and used the site survey tool to determine the number of APs needed and how many floors each one would cover,” Claude said. “The test was far better than expected, and I got fantastic results.

“The site survey tool is a ping/ICMP—Internet Control Message Protocol—tool that measures a flurry of packets between a wireless client and a host. I ran 50 sets of 100 packets for each survey. It gave time responses for each packet and averages,” he said.

Through his testing, Claude was able to figure out that he would need four APs to cover the entire living-quarters building. One problem he discovered with wireless during his tests was that he needed to keep the access points out of the kitchens in the communal areas between the living areas.

“I quickly learned that microwaves and APs don't mix well, so keep them apart,” he said.

Building out the wireless LAN
Putting the wireless network together certainly wasn’t the logistical nightmare that a hardwired network could have been in the residential building. “The hardware setup was extremely easy, as there was only one location for each AP. It took about a week total to do it all,” Claude said. “The wiring took several days to cable due to the construction of the building.”

The wiring Claude is referring to is the Cat5 cabling to connect each of the four APs spread throughout the building. About midway through the building, Claude placed one of his two hubs to act as a repeater for the two APs farthest from the hub that sits between the APs and the firewall for the corporate LAN. To power the APs, 3Com includes PowerBase-T modules that send electrical power through the Cat 5 cable to the APs.

Positioning the APs took the most planning, and Claude found that while the survey tool was best for quickly testing the network, another software tool included in the 3Com solution was even more helpful.

“I split up the building and basically chose the center of each section and used that as a starting point. I then just placed the hub on a counter, floor, or chair and tested the area using the 3Com Launcher,” Claude said. “[The Launcher] has a nice little graph that shows real-time connection speeds and noise. I then walked around, recorded results, moved the AP, and started over.

“Positioning is the key thing, and I still have one floor of one section that is giving more trouble than the rest. There is a big dead spot, and I’m having a hard time figuring out why.”

The number of barriers between the AP and the individual wireless NICs are the limiting factor in placing the APs, and while steel and Gyproc didn’t seem to affect the signal strength, cement seemed to have the biggest effect. Claude also found that placing the APs in open air worked best, after having little success trying to place one above the suspended ceiling in the building.

As for configuration and management, the APs use a Web interface, and Claude found that it worked well after he was able to upgrade the firmware in the APs. That process was somewhat labor-intensive, however, since he had to use a direct serial connection to each AP to upgrade the firmware.

Insights gained
Although Claude’s situation is fairly unusual, it is a good example of a topology where a wireless LAN can provide excellent cost and implementation benefits. It’s also a pretty good example of how to make a good business case to management for implementing technology to improve the organization.
What is your experience with wireless network connection speeds? Is it a viable option for certain office situations? Share your thoughts on the matter in a discussion below or send us a note.
0 comments

Editor's Picks