Case study: wireless rises to university challenge

The University of Birmingham is one of the biggest in England, with 30,000 undergraduate and postgraduate students, as well as 6,000 staff. The main campus in Edgbaston covers more than 250 hectares, with a second site in Selly Oak stretching over 80 hectares.

To help the work of staff and students, the university embarked on a major network upgrade in 2004 that has seen it install a 10Gbit/s core and 1Gbit/s links to desktops across both sites. As the university’s network manager, John Turnbull has been a very busy man for the past four years. Not only has he overseen the upgrade to the wired network, but he has also been managing the deployment of a separate wireless infrastructure covering the entire university.

“The network rollout has been a massive job. We’ve built telecoms rooms in every building and put flood-resistant Category 6 network cabling in all of them,” he said. “The standard desktop connection speed was 10/100Mbit/s, but now we have gigabit connectivity as standard.”

This boost in bandwidth has been welcomed by a number of the university departments, Turnbull said, citing the nuclear magnetic resonance (NMR) laboratory, which needs to transfer huge amounts of data contained in NMR spectral data files.

As to why it decided to deploy a campus-wide wireless network when it was already in the process of rolling out high-speed connectivity across the campus, Turnbull said, “We wanted to enhance the user experience for staff, students and visitors to the university, giving them convenience and more flexibility.”

Turnbull’s decision to build a separate wireless infrastructure in parallel to the wired LAN was driven by the need to ensure the highest levels of security and resilience. But there was another factor: Turnbull could not bring himself to waste all the old fibre left over from the wired network upgrade.

“When we moved from 8Gbit/s connections made up of eight 1Gbit/s links to 10Gbit/s connectivity across a single pair of optical fibres, we were able to recycle around 35 expensive single-mode fibre pairs, and also some 1000Base LX mini-gigabit interface convertors for the wireless network,” he said.

Turnbull said security was the overriding consideration, however. “The main reason we haven’t integrated the wireless access points within our main campus network is that I wasn’t convinced about wireless security,” he said.

The university’s security architecture is built around Juniper NetScreen 5200 Series firewalls. There is an overall site firewall, and firewalls installed in each building. “If you have access points [APs] inside the building, then a security incident on the AP could mean somebody has penetrated the secure side of your network,” Turnbull said.

Keeping the two networks separate minimises the threat to data should either one be compromised. “At one point the wireless network does link back into the main wired network via another firewall, so if there was a security incident on the wireless network, then all we have to do is pull out a couple of fibre connections and the wireless network would be completely isolated,” Turnbull said.

This parallel architecture has the added benefit of ensuring that users have a backup means of accessing data in the event of one of the networks going down.

The university built its wireless network using technology from Foundry Networks. It aims to deploy more than 650 IronPoint Mobility APs as well as five IronPoint Mobility wireless controllers. Power-over-Ethernet is provided by 140 Foundry FastIron 2402-PoE switches and 30 FastIron 12GCF edge switches.

The university’s senior network specialist, Chris Lea, said the key feature that attracted it to Foundry was its virtual cell technology, which is designed to reduce channel interference, allow better roaming performance and preclude the need for site surveys.

According to Foundry, this virtual cell technology allows a client device to see the wireless LAN as a single large AP as opposed to a series of individual APs.

“This allowed us to install APs into a building, and set them all to a single channel, creating a ‘blanket’ WLAN,” Lea said. “With this ‘channel blanket’, roaming decisions are taken away from the client and handled by the wireless controller in the background, giving automatic hand-offs.”

Lea said the alternative to this would have been to use a traditional non-overlapping 1-6-11 channel structure, whereby APs are separated by enough channels to limit so-called adjacent channel interference. With this approach, wireless LAN managers normally need to do a site survey to ascertain optimum position and coverage for the APs.

Lea also pointed to the benefits of the “switch-like fairness” of the Foundry wireless kit, which uses a time-slicing system combined with a round robin approach, and is designed to give all users an equal share of bandwidth. “This means users downloading large data files don’t hog the network and makes for far better quality of service,” added Lea.

Turnbull said the fact that his department has not had to conduct an extensive site survey or spend time troubleshooting interference has meant a considerable cost saving.

The wireless rollout, which is one of the biggest of its kind in the UK, was planned in phases. “In phase one, we deployed wireless in lecture theatres and student congregation areas such as coffee lounges. In phase two, which is under way now, all the areas not covered by the initial rollout, like the rest of the building spaces, other open areas and the sports fields, will be backfilled,” said Turnbull.

By the end of this year, the university hopes to have complete coverage. “So far we’ve installed 300 of Foundry’s APs, and we’ll be installing a further 360 to complete the job,” he added.

Turnbull said visitors to UoB will see three service set identifiers (SSIDs) when they fire up their laptops. “First, there’s UOBWLAN for staff and students, using wireless protected access and 802.1x authentication against Active Directory, which is populated by our identity management system,” said Turnbull.

There is also the eduroam SSID, which provides roaming access to the Janet academic network for visitors from other participating sites. “Somebody from another university could come to Birmingham and access our wireless network, but the authentication would be dealt with by their home network site,” said Turnbull.

Lastly, the UOBGUEST SSID is for people who are not part of the university, but require guest internet access. “We provide a web page re-direction for them, and they’re connected by a private ISP to the internet,” said Turnbull.

The university has staged major conferences using its WLAN and students can access their own web portal, together with a virtual learning environment, which has lecture notes posted by staff. “We staged the international Prince English Squash Grand Prix last year and laid on wireless access for journalists covering the event,” pointed out Turnbull.

Future plans for the network include an 802.11n rollout in around 18 months’ time. However, Lea said users are happy with the current performance, adding, “We do have to get some return on investment.”

Turnbull said, “We’re also trialling Wi-Fi phones, which we’ve had good results with, and looking at multicasting live video of sports matches and conferences over the wireless link. We’ll also be offering the students IPTV later.”

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