Innovation thrives in optical transports

When the National Fiber Optic Engineers Conference opens today in Orlando, Fla., it will gaze out at a landscape parched by three years of drought in the optical-transport industry. When broadband end users and access carriers show few signs of a business upturn, what hope is there for equipment and carrier players in backbone markets still suffering from fiber overcapacity?

With fiber so plentiful from long-haul to enterprise access point, design engineers would seem to have little incentive to experiment with concepts that improve bandwidth utilization. The biggest surprise of the recession has been the continued efforts, ranging from the physical up through the application layer, to optimize optical-transport channels.

Sometimes, this means returning to old friends. In this week's InFocus, Nortel Networks and Mahi Networks both find common cause in Sonet, which some predicted would be dead by the 21st century. Because it can meld data and circuit traffic effectively, Sonet is finding new life, carrying storage-cluster traffic and serving as an enabler for generalized multiprotocol label switching (G-MPLS).

At the physical layer, another old friend, the four-wave multiplexed LX4 standard for 10-Gbit services, finds new respect. Bill Woodruff of BitBlitz compares this trend to the story of the tortoise and the hare, and provides arguments for looking again at LX4 transceivers.

At Layers 2 and 3, MPLS continues to find favor for more services than just flow definition for quality of service. It is being used for Layer 2 and 3 virtual private networks and for special Ethernet private-line service. Riad Hartani shares Caspian Networks' perspective on using MPLS and Internet Protocol together in flow-based networking, while Esmeralda Swartz of Avici Networks describes how the melding of Sonet and IP/MPLS features provides the equivalent of "real-time IP." And Stephen Thomas of Wave7 Optics defends Layer 3 switching as more efficient than Layer 2 flows.

Together, our six contributors in print and online show that while optical-transport markets may still be stuck in the doldrums, innovation continues in making that transport as efficient as possible.