Combat-ready Optical demonstrations display next generation network >BY SANDRA GUY, News Editor

A battlefield commander needs a quick, reliable damage assessment of the latest bombing mission to make strategic decisions. Should he risk another pilot's life in a second strike to defeat the enemy? Obtaining and assessing such complicated information from satellite intelligence requires lots of planning with today's technology. "By the time you finish planning, the war is over," said Ben Hui, program manager for the Defense Advanced Research Projects Agency's technology office.

The agency is helping fund a consortium that is developing technologies to speed critical information over a fiber optic network. Two local area networks-one in New Jersey and another in Washington, D.C.-would be connected over an AT&T long-distance link (see figure). The optical networking layer ideally would support all telecommunications standards, including broadband, multimedia, asynchronous transfer mode and Sonet services ranging from OC-1 to OC-192.

The Multiwavelength Optical Networking consortium, or Monet, last week announced that it has demonstrated two networking testbeds. The technology uses multiple wavelengths, or colors of light, to transmit billions of bits of information per second through optical fibers with greater flexibility and reliability than ever before. The achievement is considered a step beyond wavelength division multiplexing (WDM). Carrier members include Bell Atlantic, BellSouth, Pacific Telesis and Southwestern Bell Technology Resources Inc.

The testbeds are designed to help the National Security Agency in Fort Meade, Md., and the Naval Research Lab in Washington send critical and encrypted messages more quickly and accurately.

But the commercial implications may be just as meaningful. The technologies underpin next generation Internet capabilities that can speed less dramatic but no less important communications such as e-mail.

Scientists from Bell Labs and AT&T Labs demonstrated one of the testbeds, which sends 2.5 billion bits of digitized information per second and features an optical layer that is format- and bit-rate independent.

"The greatest benefits of multiwavelength technology will be realized in local exchange networks when it's possible to dynamically set up an optical path to meet a customer's service request, supporting whatever bit rate or signal format the customer wants," said Joseph Berthold, executive director of network systems research at Bellcore. The ultimate goal-a mostly optical network-would let carriers transmit a variety of services without having to buy or upgrade equipment each time a new service is added.

The second testbed, demonstrated by Bellcore scientists, features a self-healing ring. Experimental network equipment on the ring would provide safe traffic delivery across a regional multiwavelength network, even when part of the network was damaged. This is the first part of a local exchange networking testbed in Red Bank, N.J., that will later include several kinds of multiwavelength switches and wavelength-routed stars, designed to determine the best mix of equipment for LANs.

"We're trying to understand the right combination of these all-optical technologies," which would have high-speed electronic switches hanging at the edges, Berthold said.

Carriers that wanted to connect Internet protocol routers that have 2.5 Gb/s output transmission ports, for example, could put those routers onto various nodes of a WDM self-healing ring without having to use Sonet transmission equipment. Carriers would benefit from the streamlined optical path, and the ring would provide survivability at a lower cost, Berthold said.

The Monet consortium is researching a third testbed with a cross-connect system that would configure networks by switching wavelengths from place to place.

Some hurdles remain, including setting network power levels properly when bandwidth is determined on the fly, Berthold said.

Douglas Pompey, program manager for Bell Atlantic, sees the accomplishments as evidence that WDM will be used extensively throughout the network. Bell Atlantic, which is involved in other WDM activity that Pompey declined to identify, has sufficient fiber in the ground to accommodate a phased introduction of WDM, he said.

Others appear equally optimistic about the technology. The Monet consortium is racing against other groups, including the National Transparent Optical Network and research teams sponsored by Japan and Europe.