In it for the long haul: Optical transport systems go the distance

A change is brewing for long-haul networks. Companies such as Qtera and Corvis are developing ultra long-haul optical transport systems that can send traffic as far as 3200 to 5000 kilometers without electrical regeneration. These systems could encourage carriers to rethink their network architecture.

Reaffirming the importance of long-haul optical networking, Nortel Networks acquired Qtera in December and gave carriers a glimpse into the future.

The main advantage of ultra long-haul optical equipment is that carriers do not have to bring all traffic down to the electrical layer every 600 kilometers for regeneration, said Scott Clavenna, principal analyst for Pioneer Consulting. Only the traffic that needs to be added or dropped must be brought down to theelectrical layer, improving network efficiency, he said.

These ultra long-haul optical systems also allow carriers to deliver services faster, thanks to network management capabilities that allow for instant wavelength provisioning. "It's not only what you can do on the hardware side, it's also what you can do on the operational side," said Glenn Falcao, executive vice president for Corvis.

Although the ultra long-haul market is young, Nortel's purchase validated the space and spiced up competition among optical equipment providers. Qtera has completed field trials with Qwest Communications, but Corvis is hot on Qtera's trail, running trials with Qwest, Williams Communications and Broadwing. Although comfortable with metropolitan area optics, Ciena caught on to the trend and added long-haul capabilities to its CoreStream product. Sycamore Networks offers a similar long-haul platform that extends traffic 1600 kilometers with regeneration.

Williams, currently testing Corvis' CorWave long-haul system, has high hopes for these systems and their network management capabilities, especially as they relate to provisioning services, said Matt Bross, senior vice president and chief technology officer for Williams. "Turning up services that may have taken 100 days will [now] take 10 days. Services that may take 10 days [to turn up now] will take one day," he said.

Williams' goal for long-haul systems is to reduce network buildout costs and improve service allocation speeds by one magnitude. "We need to meet the bandwidth-on-demand requirements of our customers," Bross said. "The pent-up demand for bandwidth has no end in sight."

Qwest also wants to meet bandwidth demands. Building an all-optical network should allow customers to raise applications to the next level without having to worry about capacity, said Vab Goel, vice president of the emerging technologies group for Qwest. "Unforcasted events happen on the Net. On top of the forecasted events, you have to be able to handle the thousands of unforeseen events."

As Internet traffic continues to grow, carriers' carriers such as Qwest and Williams look to provide low-cost bandwidth and reliability. Qtera touts its system's ability to go 5000 kilometers without regeneration as a cost-effective solution for survivability.

"It eliminates the need for regeneration on diverse paths," said Fahri Diner, CEO of Qtera. Sometimes twice as long as the primary path, backup routes can be expensive due to the electrical switching. By keeping the diverse path traffic in the optical layer for up to 5000 kilometers, carriers can provide survivability at low cost.

While the Qtera and Corvis systems enable traffic transmission from 3200 to 5000 kilometers, the network of the future will not be a point-to-point network that connects big cities. Instead, a mesh network with optical switches at smaller cities across the country, where carriers will add and drop traffic, is more likely, said Steve Alexander, vice president and chief technology officer for Ciena. "Fixed traffic patterns only make sense if you can predict the pattern."

Predicting a pattern is as tough as predicting a leader in long-haul systems because the market still is young, Clavenna said. While the Corvis and Qtera systems are similar, Nortel's acquisition of Qtera and the fact that Qtera's system already has been proved on Qwest's test bed are plusses. "In terms of delivery and positioning, Qtera has to be considered a leader," he said.