Vendors look for more 'utility' in optical nets

Two years ago, every optical networking startup claimed to be designing a new type of optical component or network element that didn't compete with existing products-some new niche vital to the future of optical networking. Now it's just the opposite.

Just about every company today, minus some R&D-level startups, has the same pitch: that its product can reduce carriers' operational expenses. Regardless of what the product is or where it fits in the network, its raison d'etre is long-term cost-cutting.

The logic here is straightforward: With their stock prices sagging and their industry under fire, carriers are reluctant to spend much on capital equipment. At the same time, they're anxious to curb losses and tighten up their quarterly reports. So what little they do spend on equipment is going to cover the components and systems that will cut their costs now and save them money in the long term.

To see where losses build up, take a look at the process of provisioning a circuit-that is, setting up a path through the optical network. A connection that spans North America can take weeks to provision because the optical nodes at every step across the continent must be configured manually by a different set of technicians. It's a long, expensive process.

Many vendors believe all-optical switching can play a role here, even though the concept has been shouldered out of the spotlight by the recession. Vendors claim that all-optical nets can cut operational expenses drastically, in part by allowing long-haul connections to travel like an express train, zipping past intermediate nodes without stopping. Current technology has the traffic translated from light into electrical form at each node, so it can be read and regenerated, then converted back into light for transmission to the next node.

With that as their starting point, vendors are trying to find some additional utility in all-optical networking.

This week's In Focus begins with an article on how a more robust management and signaling infrastructure will play an important role in future success. Optical hardware designer, Eddie K.H. Ng and his colleagues at Tropic Networks Inc. discuss how optical management needs to include the monitoring and identification of particular light paths, to allow tracking of the multiple data streams that might be carried within a wavelength.

And Alastair McAulay, vice president of research at All Optical Networks explains in his contribution how how all-optical switching can compensate for the slight wavelength variations in transmitters. McAulay discusses the design benefits of wave-shift multiplexing (WSM) with "the availability of protocol- and bit-rate-transparent optical signals throughout, thus allowing the customer to change protocols or bit rate without reconfiguring the system hardware or software."

And an added advantage to using all-optical channel cards, he notes in his article, is "that they can be inserted into or removed from an operating WSM system without any difficulty. Because photons are uncharged, unlike electrons, there are no voltage or current spikes on breaking or making optical connections."

Several exclusive online articles offer more insights and innovative concepts into new directions for wavelength-based design. Greg Penz, director of product management at Innovance Networks, notes that a particular wavelength's reach depends on the characteristics of the underlying fiber. With some juggling, it's possible to assign network paths based on the distance required, so that wavelengths that have farther to go can travel along cleaner pathways.

On the board-level front, Michael Worry, chief executive officer at Nuvation Engineering, details the construction of Sonet-Ethernet bridges that would allow the optical network's legacy Sonet equipment to interact with newer Ethernet networks. And PMC-Sierra's Sonet/SDH project manager, Greg Wynans, reviews a method for "slicing" data across a switch fabric to increase capacity while avoiding the complexities associated with multistaged architectures.

Sab Gosal, director of product marketing at Polaris Networks, revisits the topic of generalized multiprotocol label switching (GMPLS), which can be used to create label-switched paths assigned to a particular wavelength or group of wavelengths.