Mobile working Toolkit

Birmingham students get Wi-Fi freedom of speech

Tags:
Coverage,
Throughput,
Cell,
Survey

Richard Thurston ZDNet.co.uk

Published: 14 Apr 2008 15:34 BST

...anywhere on campus. So, not only is fast roaming essential but also comprehensive network coverage, to stop calls dropping out.

To survey or not to survey?
Usually, organisations requiring blanket wireless coverage of a particular area would undertake a site survey to find out where the access points need to be located. It is all too easy to guess where to put access points and then discover the black spots when it's too late.

But the university declined to use site surveys beyond some initial in-building work and is instead relying on a more iterative approach for its outdoor coverage. "Traditionally, site surveying has been time-consuming," said Turnbull. "The traditional set-up is to survey so there's no interference."

Turnbull claimed that, between himself and Lea, they had a good feel for where the access points needed to be located.

The virtual-cell feature wasn't the only reason the university chose Foundry's technology; it calculated that the equipment outperformed that of Cisco.

"We wrote a tender, and Cisco, Foundry, Extreme, Nortel and a few others came back," said Turnbull. "We asked for a sample of equipment, which we rigorously tested in our lab. We blasted the network and found that Foundry network equipment, in terms of performance, outstripped Cisco and Extreme."

Turnbull added that he was further put off Cisco's equipment because the proposal the company had put forward was based on three different platforms. Cisco has, over its 24-year history, bought 126 companies, which means that, despite all its integration work, the company's products are still based on a wide range of operating systems and user interfaces. "Cisco suggested three switches from different families of products. The complexity of it would have been massive compared with what we got from Foundry," Turnbull said.

A phased approach
The university is adopting a two-phase approach to building its Wi-Fi network. In phase one, which is complete, Turnbull and Lea installed 300 access points in numerous academic buildings, libraries and coffee areas. Some of that wireless coverage propagates outside to areas such as the sports fields. Phase two, on which the duo are now embarking, will see current black spots filled in across the campus with a further 360 access points.

Once Turnbull and Lea have completed phase two, they will consider focusing their attention on upgrading the wireless network. Each access point currently supports the 802.11g maximum theoretical throughput of 54Mbps, which the duo believes is sufficient for the university's current needs. However, with an average of 20 students accessing the Wi-Fi network for the first time every week, they said they believed that could change in the future.

Most wireless-networking vendors have already started selling equipment based on the latest generation of Wi-Fi, 802.11n. 802.11n equipment promises a theoretical throughput of 300Mbps, as well as techniques for reassembling radio signals which have bounced off multiple surfaces. Although vendors have started selling the equipment, their kit is only based on a draft specification, not an international standard.

"In the short term, with virtual-cell technology and the ability to increase capacity by throwing in access points, we're covered for performance for some time to come," said Turnbull. "We need to be at the forefront, but it's not clear at the moment how 802.11n is going to be implemented."

One of Turnbull's concerns is over the power requirements of 802.11n access points. Currently the devices cannot be powered using standards-based Power over Ethernet over a single cable; the access points typically use 18.5W, while Power over Ethernet can supply only 15.4W. Given the uncertainty, Turnbull has gone to extraordinary lengths by installing two cables to every access point, in case the problem is not resolved.

The university's technical advancements won't stop there. The institution plans to make full use of the Wi-Fi network to stream live audio and video across its network from campus sports matches. It even has plans to stream live rugby across the SuperJanet academic network to halls of residence at the University of Warwick when the two teams meet next season.

With all these technical achievements, including the convergence of its fixed and mobile networks, the university, surprisingly perhaps, still maintains a separate, legacy voice network. Many universities have already converged their voice and data communications.

But Turnbull is in no rush. He said that trials with Microsoft's Office Communicator and mobile devices will more than suffice for the university's convergence efforts in the short term and it will be "two or three years" before anything changes on the fixed voice network.

With the increasing availability of Wi-Fi voice on campus, Turnbull said he sees little need to invest in fixed-line voice. "Wi-Fi phones raise the question of whether you need a fixed-line phone, " he said.

How the University of Birmingham's network measures up

The Wi-Fi network is scheduled to cover 250 hectares by the end of the year at the university's main campus in Edgbaston. Satellite campuses in Selly Oak and Stratford-upon-Avon are also expected to benefit from Wi-Fi coverage
The campus is so large that the switches have to be 2.5km apart
Secure Wi-Fi access will be granted to 30,000 students and 6,000 staff, as well as visitors
Each week, twenty students access the network for the first time
The university has purchased 660 access points at a cost of around £250,000
LAN cost savings of £87,000 have been achieved
Over 45,000 ports have been connected using Category 6 copper
A fibre backbone and four access points have been installed in the university's Great Hall, a listed building in which nothing can be attached to the walls