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Optical/IP

Germany To Push Limits On Scalability

A project that pushes the limits on large scale optical networks got off the ground in Germany last Thursday, when the first sites were connected to G-WIN (Gigabit-Wissenschaftsnetz), an Internet backbone serving the country’s research community.

Over the next few months, the network’s operator, DFN http://www.dfn.de, will connect a total of around 700 sites making it by far the largest research network of its type anywhere in the world. (DFN is short for Verein zur Förderung eines Deutschen Forschungsnetzes e.V, an association for the promotion of German research networks).

Comparable networks in North America – the Abilene backbone underpinning Internet 2 in the U.S. and Canarie's CA*net 3 backbone in Canada – only connect 60 to 80 sites, according to Marcus Pattloch, a member of DFN’s steering group. That’s because these backbones only provide very high bandwidth connections. Research establishments wanting smaller bandwidths – 45 Mbit/s or less –connect indirectly, through ISPs, according to Pattloch.

In Germany, every member of DFN will get a direct connection to G-WIN - at a breathtakingly low price. “We’re giving them 622 Mbit/s and 2.5 Gbit/s for the same price as a 2 Mbit/s connection,” says Pattloch.

The bargain isn’t likely to be replicated in commercial networks anytime soon, partly because DFN is subsidized by the German government. The government also put “enormous political pressure” on Germany’s incumbent carrier, Deutsche Telekom AG http://www.dtag.de to give DFN a good deal, according to Pattloch.

In addition, Cisco Systems, Inc. http://www.cisco.com donated 10 of its GSR12016 core routers to the project. That put paid to going with Juniper Networks Inc. http://www.juniper.net, according to Pattloch.

Under government pressure, Deutsche Telekom has sold dark fiber for the first time on the G-WIN project. It's a big breakthrough and it makes a huge difference, according to Pattloch. It means that optical equipment can be housed in DFN facilities rather than Deutsche Telekom sites, which makes troubleshooting far simpler.

Deutsche Telekom has also developed a management system that speeds up the provisioning of connections over the G-WIN backbone and enables DFN users to see what's happening on the network, via a Web site. Much of this is based on software from Alcatel SA http://www.alcatel.com, which supplied the DWDM and SDH equipment on the project.

This doesn’t make G-WIN “the world’s first optical virtual private network”, as Alcatel claimed in a recent press release (see Alcatel Claims First "Optical VPN"). “For an open research network to be considered a VPN is a contradiction," says Pattloch. The management software also doesn't use any sort of IP tunneling protocols or VPN standards, he adds.

Nevertheless, the ability to monitor G-WIN and troubleshoot optical equipment without any difficulty is likely to prove crucial in the coming months, as DFN connects more and more sites. Pattloch recognizes that the association will be sailing into uncharted waters in optical networking. “We hope it will work. We think it will work. It’s really a question of how the network will scale internally,” he says.

Right now, the scalability of management software such as Alcatel’s is a big unknown. Carriers are worried that they’ll run into similar problems to the ones some of them experienced when frame relay networks grew to a large size – problems that led to prolonged black-outs of large numbers of customers. At present, the only way of allaying these fears is to emulate large scale networks (see Sycamore Demos Software Scalability).

For these reasons, DFN's experiences with G-WIN are likely to attract world-wide interest. Like other operators of research networks, it’s in the fortunate position of having users that don't rely on continuous network availability. In many cases, they're developing high bandwidth applications that won’t find a use in commercial environments for a few years.

The timescale on rolling out DFN's new network is much tighter. All 700 sites must be connected to G-WIN by November 15, because the contract for DFN’s existing backbone will expire at the time. There are no plans to continue its operation after that date, says Pattloch.

By Peter Heywood, international editor, and Marguerite Reardon, senior editor, Light Reading http://www.lightreading.com

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