Figuring out DWDM: Digital Lightwave intros optical test system

Dense wave division multiplexing received a long-awaited blessing last week when Digital Lightwave announced a remote testing and monitoring system based on the transmission technology.

The company's Network Access Agent for DWDM is the first commercial release of a centralized DWDM testing and monitoring system. Others currently are working on testing and monitoring systems, but the optical testing market has not kept up with the carriers using the technology.

"That is the real problem with DWDM. The market moving toward optical testing equipment is really slow," said Bill Gorsuch, senior engineer at Level 3 Communications. Level 3 is testing the NAA for DWDM for use with its network.

Digital Lightwave's system allows carriers to test up to 25 DWDM fibers and embedded OC-48 signals on equipment from various vendors. "This will actually let them look at the individual channels inside the DWDM network," said Reuben Prichard, director of systems engineering and architecture at Digital Lightwave.

Testing DWDM networks at the optical level is essential to bringing the technology to the forefront. "DWDM is going through an evolution at the moment. What Digital Lightwave is looking at is when it starts carrying data, voice and video," said Alan Stewart, president of Network Interface Corp. For DWDM to be useful, "you've got to be able to run not only transmission tests, but tests above the transport and data link."

The testing system is geared toward long-haul systems and is placed at the optical amplifiers, which are 80 kilometers apart. The units are controlled centrally, which enables carriers to constantly see what is happening at the optical level. Currently, nodes set off errors, but often they're too general. "The ability for vendors to provide testing inside their boxes right now is minimal," Stewart said.

Key to the system is its preventive approach, which helps carriers fend off problems as they happen. "When you have that much traffic, and the potential for lost profit is that great, you want to be proactive," Prichard said.

Prichard sees potential customers in large companies that already have DWDM systems and smaller carriers just beginning DWDM network buildouts. "The new companies are going to DWDM immediately, and when they grow, they have to be able to manage the network," he said.