radio

U of L wireless network – hurdles and behind-the-scenes efforts

Last year the University committed $20,000 to upgrade the wireless in some of the older residence buildings which dramatically improved coverage for students there, plus another $80,000 to improve the coverage in classroom spaces, says Jeff Oliver, Network Team Lead in IT Services. “Over the next few months, we will be conducting tests across the campus to determine where other gaps exist.”

Wireless surveys have already been completed in University Hall and Markin Hall which has helped us to identify some issues already. IT Services staff need to physically pace off every space with equipment that measures the wireless signals which then provides visual heat maps of how well wireless signals are reaching offices and workstations. “These heat maps help us figure out where new access points will help, and where they won’t,” adds Oliver.

E8 HeatmapWi-Fi coverage in E8 of University Hall: the darker colors represent good Wi-Fi coverage and are generally closest to the access points. The lighter areas show poorer Wi-Fi signals. The green line indicates where a staff member walked the area and the dots on the line represent ‘pings’ to the access points.

Wi-Fi signals do not penetrate solid materials well, particularly steel and concrete, or fluids. A person standing between a device and an access point can interfere and simply absorb the signals. The more obstacles, the weaker the signals.

Imagine being in a room with 10 radios that are all tuned to different radio stations…

“Noise, also known as an abundance of radio signals, is also a big problem with wireless. The more noise, the worse the connection. Imagine being in a room with 10 radios that are all tuned to different radio stations – can you listen to them all, or pick out just one? Can you pick out an individual conversation in a room where 100 people are all talking at the same time? In the wireless spectrum the same concepts apply. The more conversations going on at the same time, the more noise overall.”

The number of wireless devices brought on campus is increasing every academic year. With each additional faculty, staff or student come one to three or four additional devices, all requesting network access–many at the same time. This means that every access point must support more and more individual devices, and the access points need to be closer together as each one can only service a limited number of clients.

…there are about 25,000 wireless devices on campus of which more than 10,000 can be active and connecting to the wireless network over the course of a day.

Oliver adds there are about 25,000 wireless devices on campus of which more than 10,000 can be active and connecting to the wireless network over the course of a day. “Our maximum concurrent connections this semester so far has been 7,000, and that number can fluctuate wildly depending on the day.” Early in the semester we were alerted to the fact that some of the network infrastructure supporting the Student@UofL and Guest@UofL networks was running at capacity, which prompted us to replace some equipment with newer technology.

So how much network traffic does this number of devices equate to?

Guest student before new router

The graph above illustrates the amount of Wi-Fi traffic on the network during one week in September: it peaked out at 300MB per second. Once the new router was installed, the higher demand was easily managed as shown in the graph below and no longer has “flat spots.”

Guest student after new router

Network staff have been working to add additional access points in 80 classrooms over the past year, and expect to be finished by December. The largest classroom, PE250, will have six access points. The rest will have roughly double what they originally had, which will greatly increase the number of concurrent connections available in classroom spaces. “We are targeting approximately 40 users per access point.”

It isn’t just a matter of attaching an access point on the ceilings, additional wiring must be installed as well as network infrastructure such as switches and routers to support the increase in the wireless footprint. Much of the work must be done when the rooms are not in use.

The demand is not only on campus. Last spring, outdoor access points were added at the stadium to provide coverage in the bleacher and track areas. “The University’s wireless network is in a perpetual state of upgrade.”

The team is constantly planning and preparing for future changes in technologies. Next year about 250 aging access points are scheduled for replacement to keep up with the changing technology used in mobile devices today.

The next time you use wireless on campus, whether it works immediately or there’s a delay connecting, keep in mind the hurdles and ‘behind-the-scenes’ efforts and costs to provide the service. Oliver reminds people to report any issues to the Solutions Centre (help@uleth.ca) so that steps can be taken to correct them.