A cloud with a silver lining

A mesh networking initiative is bringing Internet access to a UK school - and its students' homes.

On first inspection Broad Oak High School, a specialist sports college in a deprived area of Bury, Lancashire, is an unlikely technological pioneer. In 2006 the school had been earmarked for closure due to falling pupil numbers, and was only saved following lobbying from the local community. Fast forward to today and the latest Ofsted report says the school is doing good work. Broad Oak is also being cited for its £140,000 scheme to construct a wireless mesh network, which will provide Broad Oak students with broadband and network access at school, and in their homes.

The scheme, known as NET@BOSC, is the latest in a series of technological solutions adopted by the school, which includes interactive whiteboards in every classroom and a cashless payment system that uses students' fingerprints instead of money. NET@BOSC has been developed in response to fears that the digital divide would see Broad Oak students fall behind pupils from richer areas, many of whom take a home broadband connection for granted.

"Bury on the whole is regarded as an affluent community," says head teacher Neil O'Connor. "But we've got levels of deprivation that nationally would be considered deplorable. Our section of the community is not affluent.

"I want these youngsters to feel as if they're at the forefront of technology because it's a massive motivating factor. Currently 40 per cent of our students don't have broadband access at home and that needs addressing."

Wireless cloud

With 90 per cent of Jobcentre adverts now stating that computer experience is required, it's clear to see why the issue of the digital divide is rising up the political agenda. During his keynote speech at last autumn's Labour Party Conference, Prime Minister Gordon Brown promised £300m of funding to provide up to £700 worth of vouchers to England's poorest families for home broadband access. However, having examined its options, Broad Oak felt that a wireless mesh network was a better solution.

"The big advantage of providing a wireless cloud is that after the initial cost of the equipment you're really just redistributing the school's existing 10Mbit/s broadband connection, so there are no ongoing costs," explains Ian Taylor, wireless specialist with Bury-based Pennine Telecom, which designed and implemented the system. "Some schools have provided 3G dongles or subsidised cable connections to pupils but when the funding runs out, so does the Internet connection. With a wireless cloud the school can even look at extending it to the local community and making money from it."

Although wireless mesh networks are not new - over 100 American cities have used the technology to deliver free wireless - NET@BOSC is the first time that the technology has been used by a UK school to provide free home Internet for its students. Encouragingly, according to ICT specialist Chris Lishman, the design and implementation of the scheme has been "really simple". The area that the school wants to cover with the cloud has been split up into several zones, which are being commissioned in stages to iron out any bugs.

The wireless network is based on the school's 10Mbit/s connection, which is distributed around each of the zones using typically five or six 'mesh heads', which are attached to lamp-posts in strategic positions around the zone. Each of these routers forms a node on the network and communicates with users and other mesh heads using the 802.11a, b and g stan-dards. Within each mesh there is a single wireless point-to-point link which acts as a backhaul to take the collected signal back to the school.

"If you have five routers in a ring, essentially each one of those routers creates its own wireless cloud - but they also talk to each other. And they're positioned so each user can access at least two or three of these nodes, so it load balances the traffic between them," says Taylor. 

Self-healing mesh network

The ability to spread the load across multiple nodes means that the system is self-healing - should one of the nodes be damaged or blocked for some reason then it shouldn't cause a disruption in service. Dynamic routing means that the signal is delivered by the other nodes. This should allow the cloud to provide students with a consistent connection that will deliver speeds between 512kbit/s and 1Mbit/s.

"Some people might think that's not very fast, especially if you're used to an 8Mbit/s connection, but you have to remember that it's virtually uncontended, synchronous and many of the students haven't had access at home before, so it's better than what they've got," says Taylor.

The NET@BOSC system is being tested in the most complex of the zones.

"My feeling is that I'd rather do the toughest zone first and nail any problems straight away," says Lishman. The biggest issue for the design of the system has been in overcoming the obstructions to the signal.

"It's a radio signal that the nodes use to communicate, so anything that blocks that signal is a problem for us," says Taylor. Consequently, much of Lishman's time implementing the system has been spent driving around the area with a pump-up mast with a mesh head on it, trying to work out the optimum position. "If it was a nice, flat open area we could calculate that the signal was going to go 500m but with so many tall buildings and trees that the radio waves can't penetrate through, it takes more time to work out where we should deploy the heads."

Should a user find that their signal is compromised, one of the simplest ways around the problem is to provide a signal booster for that home; however, an even more low-tech solution will hopefully mean that signal interruption is less of a problem.

"The council has been working with us throughout the scheme," says Taylor. "When we've worked out which points are ideal, rather than using the existing six-metre concrete lamp-posts, we will replace them with eight-metre metal ones. These not only support the weight of the units but are in the optimum positions to deploy the signal around the mesh."

Despite the effort and expense of providing the mesh network, Broad Oak's head teacher is adamant that the investment in technology is more than about having the latest gadgets.

"For me, ICT is all about trying to make our kids feel that they're at the cutting edge and they deserve that because it's huge for their learning," says O'Connor.

The reaction to the scheme also suggests that Broad Oak's experiments will become a blueprint for other schools to follow and that in future your local school might also be your ISP.

"I've had half a dozen schools getting in touch to talk about how it's worked and I believe the local authority has had other councils getting in touch about how to replicate it. Plus, the kids are really excited because the 'Newsround' TV show is coming to do a piece about it."

It seems that Broad Oak is living proof that some clouds really do have silver linings.

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