Dominating discussions at this month's National Fiber Optic Engineers Conference in Dallas are optical platforms that allow carriers to incorporate next-gen services such as IP VPNs, a flexible range of Ethernet-based applications and video-oriented capabilities into the existing infrastructure while streamlining the operations, interconnection and provisioning aspects of that infrastructure. Raise revenue, cut opex and, voila, the capex pain goes away, or so a lot of vendors are hoping.
One of the first carriers to put these new capabilities to use on a massive scale is WorldCom Inc. Notwithstanding its financial difficulties, the company is rolling out a comprehensive suite of Ethernet services over its SONET footprint using the Resilient Packet Ring capabilities of the optical Ethernet platform provided by Nortel Networks Ltd. By supporting provisioning in bandwidth increments of 1mbps and allowing the carrier to maintain quality-of-service control in accord with service level agreements, optical Ethernet becomes "an optimized platform for services like Internet access, IP VPNs, Web hosting and Web centers," says Joe Cook, senior vice president for global engineering at WorldCom.
The carrier is delivering metropolitan and private line Ethernet over the platform to 84 U.S. cities and launched Internet access over Ethernet and Ethernet VPN in seven of those markets, including Chicago, Dallas, New York, San Francisco, San Jose, Northern Virginia and Washington, D.C. The steps WorldCom is taking widely are seen as harbingers of what's to come now that capabilities such as RPR over SONET are entering the marketplace.
"We believe the retail metro Ethernet services revenue is set to increase sharply over the next five years, reaching over $4 billion by 2006," says Marian Stasney, senior analyst at The Yankee Group. "WorldCom's Ethernet services meet the demand that is clearly there."
Nice Timing
Vendors report the Bell companies quietly are pursuing use of these new optical capabilities at an aggressive pace to enable new applications in the Ethernet and other domains as well as to establish the means for efficiently provisioning and managing all types of legacy services.
"We're coming into the market at precisely the right time, because, no matter what you're hearing about capex spending cuts, carriers realize they need to make use of new technology in order to expand revenue and lower their operational costs," says David Frost, director of marketing for startup Meriton Networks. Meriton brought its first product to market at the recent SUPERCOMM convention in Atlanta.
Meriton has lined up a "Tier 1 North American incumbent" to test its new optical add/drop switch, Frost says. The company sees an opportunity for technology that supports delivery of transparent wavelength services across the metro all the way to end users -- the provisioning of services by wavelengths in such a way that allows all points of interconnection and transport to accommodate added services without having to make adjustments at every ring junction, he says. Rather than treating each wavelength as a point-to-point connection between cross-connects, the Meriton OADX sets up any-to-any connectivity so the wavelength is bridged across connection points and "rolled" to an available wavelength on the next link.
"By performing the switching between access rings and core rings in this fashion we reduce the number of fiber links and WDM channels, which translates into a very significant cost reduction," Frost says. The OADX product suite, including a 128-by-128 wavelength core and a coarse WDM access ring switch, employs the optical network management capabilities embodied in GMPLS (generalized multiprotocol label switching) to keep tabs on service performance and to reserve paths across the network, he notes.
Fujitsu Network Communications Inc. is another vendor embracing DWDM metro technology on the assumption that, done right, the efficiencies of such architectures are too great to ignore. The company's next-generation Flashwave 7500 metro ring platform includes an all-photonic protection switching capability based on use of a tunable laser in each line card that obviates the need for two transmitters and an OEO conversion.
Fujitsu executives dismiss the notion that DWDM isn't a good solution for the metro core. They suggest the mistakes of the past have provided a roadmap to success that their company now has navigated successfully. The 7500 system allows wavelength services such as gigabit Ethernet to be added incrementally and scaled to reach more customers on a node-by-node basis without disruption to existing services, says Bill Erickson, senior vice president of product planning at Fujitsu.
"Many early generation metro DWDM products failed to provide carriers with a viable, long-term migration plan," Erickson notes. The problems included lack of in-service scalability, no access to individual wavelengths at connection points across the metro, the need for manual power balancing and conformity to carrier-class transport requirements.
The 7500 is designed to support all metro applications with up to 10 nodes in a 400km ring at a density of up to 40 wavelengths per fiber. Once the system is engineered, carriers can add line cards to support new services and connect any wavelength between any two nodes automatically, says Eric Koopferstock, product director for metro optical networks at Fujitsu. "Each wavelength is fully independent, which allows you to add or delete wavelengths at any point without having to match bands at the nodes," he says. "System gain balance is done dynamically from the core platform."
Adding to the flexibility, Fujitsu supports multiple services from each category of line card, eliminating the need to change out cards as services are added or altered. For example, one line card supports 10 gigE and OC192 SONET, Koopferstock says. Other line cards offer a variety of options in Ethernet, SONET, Fibre Channel and other service classes in the range of line rates from 100mbps up to 2.7gbps and, in the case of OC3 and OC12, the software to support changeover to those services will be delivered later, he adds.
Good Grooming
Sycamore Networks Inc., focusing on DWDM inefficiencies at the points where long-haul and metro networks meet, has introduced a new optical switching platform that compacts the wavelength grooming and, in the case of ultra long-haul applications, super forward error correction as well into a single OEO module. Company officials say the benefits of the new platform include a 66 percent reduction in the cost of optical transponders used at interconnection points between metro core and long-haul networks. Sycamore also is one of the first suppliers to introduce ITU G.707-based virtual concatenation for metro optical switching of gigE services.
Bonnie Sitsis, director of product marketing at Sycamore's network switching unit, says that, along with cost reductions, the company is making it much easier to manage services across mesh as well as ring networks. For instance, the new switching platform collapses all the grooming into a single transponder, thereby eliminating the bridging to 1310nm lightwaves in the conversion process from 1550nm wave-lengths on one side of the network interface to 1550nm wavelengths on the other side, she notes. It also incorporates an optical bypass so only wavelengths that need to be groomed go through the OEO conversion.
With the introduction of virtual concatenation, which breaks Ethernet packets down into the basic TDM frames used in SONET in a way that maximizes use of available time slots, Sycamore is making it possible for service providers to create services that feature mixed gigE protection schemes on a per-circuit, per-application basis, including mesh protection, Sitsis says. Carriers can offer full protection services for a portion of the overall service rate and partial protection for the remainder of the service rate, she explains.
The company is augmenting the G.707 capability by supporting transport of constituent circuits in this service package along independent circuit paths, which improves use of available capacity and enables the traffic to avoid network choke points, Sitsis says. "If you're out of capacity on a particular link, you can't take that path until you upgrade the node," she adds, noting that in a big city like Atlanta, there can be as many as a hundred rings to traverse from one end of the metro to the other. "Basically, we've added mesh restoration to SONET."
Shifting Responsibilities
Along with support for concatenated Ethernet over SONET, one major trend in optical product developments entails a shift of grooming and switching functions away from the central office toward the network edges, which eliminates a lot of the backhaul transport and space-consuming processing associated with traditional central office-based operations. A case in point, Metro-Optix has taken this trend to a new level with the introduction of release 2.0 of its CityStream 5000 platform.
"We're adding wideband cross-connect functionality, which we're discovering is in high demand right now," says Dana Hartgraves, vice president of product marketing at Metro-Optix. "So now, in one platform, we can support next-generation SONET add/drop multiplexing at OC3 to OC48 rates, ATM edge switching and service multiplexing, as well as offering 10,752-by-10, 752 VT 1.5 (virtual tributary) circuit switching capacity."
This moves the company a step closer to creating an environment where the intelligence of cross-connects, ATM switches and IP routers resides at the edge of the network, Hartgraves notes. "We'll be adding support for IP and Ethernet next year," she says.
Tellabs reports it, too, is getting traction for combined cross-connect/ADM functionality as embodied in its 6400 edge platform, which it has augmented with Ethernet-over-SONET virtual concatenation.
Broadwing plans to deploy the 6400 switch to accommodate demand for its new MultiConnect product suite, which supports rapid provisioning of services to a customer's multiple locations. "This is an excellent example of our success-based capital model," notes Ed DeLong, Broadwing's vice president of network planning and engineering. "The deployment of the Tellabs switch has enabled us to cost effectively add a next-generation optical grooming platform that can profitably scale with demand at a fraction of the cost of traditional grooming."
The Broadwing and WorldCom deployments appear to be representative of the adaptation to new technology across the industry now that the lid is tightly on capex. Both companies tested the waters with launches of new services before plunging ahead with the capital spending required to support those services on a ubiquitous basis.
With plenty of technology to use in moving up the revenue curve over the networks they have in place, carriers are positioned well to insulate themselves against unnecessary spending binges. Now it's just a matter of how far market demand for new services will drive spending for these new platforms.
METRO OPTICS FACTOID
The latest market and technology assessment report from Pioneer Consulting, Metro DWDM: Global Opportunities and Strategies in the Metro Market, predicts the market opportunity for Metro DWDM systems will increase from almost $1.4 billion in 2001 to nearly $12.6 billion by 2006.
