SuperJANET was not built to handle the vast amounts of data now generated by facilities such as Cern, but a new network will be able to beam even the biggest packages round the globe. Judy Redfearn explains
Some modern research techniques generate too much data to send across the academic network SuperJANET4 without causing serious jams for everyday network traffic. So the Joint Information Systems Committee is commissioning a different type of network, UKLight, to keep data-intensive research traffic separate from routine SuperJANET use. Some early adopters have been putting it through its paces.
For many researchers, the big attraction is UKLight's ability to continuously stream data down dedicated optical fibres between network nodes, making it particularly suitable for applications where enormous amounts of data need to be sent from one point to another, for example from a radio telescope or particle accelerator to a data-processing centre.
SuperJANET4's packet-switched architecture is best for sending many small messages, such as e-mails, between a large number of sites. But using a packet-switched network to send vast amounts of data from one site to another is a bit like posting a PhD thesis to an examiner one word at a time - a highly inefficient process. So although UKLight's nominal top data transfer rate is the same as SuperJANET4's (10 gigabits per second), the different network architecture means that research users are far more likely to achieve these rates.
The United Kingdom Education and Research Networking Association (UKerna), the organisation that provides SuperJANET, is managing and installing UKLight on behalf of Jisc. So far, nine main nodes are available for regional networks to connect to. But by the end of the year, UKLight will become an integral part of the SuperJANET upgrade (SJ5) and all 19 regional networks will have access to a main node. To use the UKLight network, a researcher needs to establish a connection between his or her application and the nearest node via the regional or local network.
Particle physicists have been among the first users to do so. They are building an international computing Grid to handle the enormous surge in data expected when the latest particle-smashing machine comes on line at Cern, the European particle physics laboratory in Geneva, in 2007.
The Large Hadron Collider will produce 15 million gigabytes of data a year (enough information to fill almost a million DVDs) when it starts to probe the physics of the universe just after the Big Bang. All this data will need to be shared, stored and analysed around the world. The UK's contribution to this international effort involves the Rutherford Appleton Laboratory receiving data from Cern and sending it on to 16 UK university sites.
During the latest challenge, a data-transfer rate of 900Mb/s, equivalent to transferring the whole of The Lord of the Rings film trilogy on DVD every three minutes, was sustained for almost four days, some of it via UKLight links.
Radio astronomers have also been using UKLight and other similar networks around the world to demonstrate how major radio telescopes, widely dispersed across the globe, could be linked to become the equivalent of one vast telescope. At the Supercomputing conference in Seattle last November, they sent data collected from the same region of the sky at the same time by radio telescopes in Europe, Japan and the US to a data-processing centre - and got an image of a distant quasar.
Other early users have been taking advantage of UKLight's enhanced quality of service. This means that data can be transferred almost instantaneously from one node to another in a very precise time sequence.
The Spice (Simulated Pore Interactive Computing Experiment) project makes use of this property to simulate and visualise a biological process of greater complexity than would otherwise be possible: the movement of a DNA molecule through a protein nanopore embedded in a cell membrane. The simulation can be shared among supercomputers at different sites and visualised at another site - even sites on different sides of the Atlantic.
The enhanced quality of service provided by UKLight's optical links allows the researchers to steer the simulation - that is, they can change an initial condition of the simulation and watch the response in near real time.
"We're transferring modest amounts of data compared with some applications," says Shantenu Jha from University College London. "What's important for our simulations is the quality of service we get with UKLight. There's no loss or reordering of data, which means that we can steer the simulations interactively."
Other applications waiting in the wings include heart modelling and music and performance projects. The latter would achieve virtual distributed performances by linking performers in different locations so that they could view each other in real time.
Connecting these applications to UKLight, however, is throwing up new issues and taking longer than originally envisaged. The problem is often in making the final connection in an institution or on a local or regional network.
"Connecting the end user's box to the UKLight node involves the end user's network administration team working in a way they're not used to," says Colin Greenwood of the National e-Science Centre (NeSC), who is managing the project to co-ordinate early users of UKLight.
The challenges are social and organisational as well as technical and scientific. "There are lots of issues involved in getting connected to UKLight. It's not simple, so projects must be prepared for that," says NeSC deputy director Peter Clarke, who helped get UKLight off the ground.
Despite these difficulties, Clarke feels that a threshold has been crossed.
"The network need no longer be viewed as a fundamental limitation to collaborative research and ultimately UK competitiveness," he says.
After a late start, the UK is now a first-class player on the global stage of optical research networks, alongside such pioneers as the Starlight hub in the US and the Surfnet and Canarie networks in the Netherlands and Canada.
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