Qwest unveils all-optical-network plans

Jan. 1, 2000

Qwest Communications International Inc. (Denver) has placed its optical future in the hands of a pair of startup companies as it embarks on an aggressive move into all-optical networking. When completed in the third quarter of this year, the carrier's new Internet-protocol (IP) network should significantly cut operating costs, network complexity, and service provisioning times, while increasing overall capacity and flexibility of service provision, according to a Qwest spokesperson.

Qwest expects to begin equipment deployment this spring. The move to an all-optical network will provide several advantages, according to Vab Goel, a vice president of Qwest and head of the company's new Emerging Technology Division. Qwest expects the use of all-optical equipment will cut operating costs by 70%, decrease the number of network regeneration points by as much as 90%, and reduce backbone provisioning cycles by 95%. The carrier will increase its IP transmission speeds to OC-192 (10 Gbits/sec), thus boosting network capacity significantly over its current OC-48 (2.5-Gbit/sec) infrastructure.

Qwest has tapped a pair of emerging optical-networking companies--Corvis Corp. (Columbia, MD) and Qtera Corp. (Boca Raton, FL)--to provide photonic transmission equipment for the backbone upgrade. At the same time, it plans to extend its current relationships with Nortel Networks (Brampton, ON, Canada), which supplies much of Qwest's current optical-networking gear, as well as with Cisco Systems (San Jose, CA) and Lucent Technologies (Murray Hill, NJ) for data switching. Qwest will turn to another startup, Siara Networks, for optical IP transmission gear for its 25-city metropolitan networks, as well as Cerent Corp., recently acquired by Cisco. Qwest also has an equity position in Juniper Networks (Mountain View, CA), a startup in the terabit IP switching space.

Goel reveals that Qwest has already begun evaluating equipment from both Corvis and Qtera over what he describes as the first coast-to-coast optical testbed. "We want to enable terabit capacity on a single fiber, we want to enable wavelength switching, we want to enable cheaper bandwidth for all our customers," Goel says. Qwest will construct a mesh-based infrastructure to provide these characteristics and will determine how well the products of the two startups meet this goal. "We're looking at the whole suite of products--the DWDM [dense wavelength-division multiplexing] and the wavelength routers. Both of them have a different way of doing the service," he reveals.

The primary difference between the way the two companies approach optical networking lies in where the restoration functions reside. Qtera's product line, which will have its official unveiling at this year's OFC show in March, revolves around a single platform that can provide terminal multiplexing, optical amplification, add/drop capabilities, and interconnection functionality when fully configured. In essence, the DWDM device hosts the restoration functions.

"At Qtera, we favor the integration of such functionality into the DWDM equipment, and we use the optical-interconnect-type devices for wavelength provisioning, not for restoration," says Fahri Diner, the company's CEO. "This enables you to get to a very scalable architecture. You do not want to force yourself to use a crossconnect that you have to scale on a port-by-port basis. Once the ports are completely used up, you can run into scalability restrictions."

This kind of integration allows network designers to simplify their topologies. "In the core of the network, we really believe that the ideal infrastructure is one in which the terabit routers are interfaced directly into a survivable photonic transport platform, and those are the only two network elements that you would need. And within that context, we are providing the survivable photonic transport piece of this puzzle," he says.

The advent of all-optic networking enables more-efficient restoration, Diner says. "When we talk about mesh, you can talk about mesh architectures where the traffic is essentially meshed and flat across the network, or you can talk about mesh-type restoration where you are trying to share protection bandwidth. Either of those scenarios works," he explains. "However, as you make the cost of bandwidth very, very low by the elimination of optoelectronic regeneration, the simplest architectures and the architectures that provide the fastest restoration, such as 1+1 schemes--or in our case, the optical 1+1 schemes--really start proving in economically. And nobody will dispute the performance advantages that you get from a simple optical 1+1 type of a scheme, simply because all restoration decisions are made locally."

For its part, Corvis favors the use of an optical switch in the network core. The company debuted its CorWave product line last June; products include the Corvis Optical Network Gateway, the Corvis Add/Drop Multiplexer, and the Corvis Optical Router. The product line is designed to aid in the evolution from a Synchronous Optical Network (SONET) ring architecture to one more conducive to very-high-speed data transmission. Both the Network Gateway and the Optical Router have a hand in restoration under the Corvis philosophy.

"In a mesh architecture, [the router] plays a very important role," says Glenn Falcao, executive vice president at Corvis. "However, until you do get a mesh architecture, a lot of the restoration function is done from the end points, from the terminal sites, similar to the way SONET [Synchronous Optical Network] would do it today. So I would say the restoration will change as the network evolves from path-diverse networks, point to point, to a full mesh network. You'll see the restoration capabilities changing in that."

Both companies appear to provide the characteristics essential to Qwest's vision: OC-192 speeds, multichannel transmission to terabit capacities, software-based flexible bandwidth provision, and extremely long-distance transmission capabilities. Qtera has demonstrated 2400-km transmission on Qwest's testbed, says Diner, while Corvis claims a transmission distance of 3200 km for 400 Gbits/sec.

Qwest hopes to keep its young charges working in parallel through the Emerging Technologies Division. "We're going to drive the new technology in the marketplace and in our network, and also drive open standards and internetworking between all the new vendors," says Goel. Both Diner and Falcao said their companies had been working with Qwest for about a year before the carrier made its announcement and that the carrier had proven extremely influential in forming their view of what functions new optical-networking equipment will have to provide.

Goel doubts that Qwest will choose one company or the other as an exclusive optical equipment vendor for the network.

"Our strategy is a dual-vendor strategy, so our goal will be to have more than one vendor in the network," says Goel, adding, "Keep in mind we already have Nortel in the network, also."

Qwest expects to unleash a wealth of new services once it completes the new infrastructure. "The key goal is, as you start getting rid of regens and you have a new, simpler way of provisioning service, how do you enable fast service activation for the customer so that they can capture nonprojected revenue when they need bandwidth on demand?" Goel says.

Qwest expects its new architecture will enable it to provision new services in a matter of hours or days, as opposed to the current cycles now measured in terms of months. These services can be deployed as wavelengths, rather than fibers, for both wholesale and retail bandwidth applications. In addition, Qwest expects to enable its customers to provision their own bandwidth as their requirements change. For example, customers could be able to switch some of the capacity purchased between Boston and Washington to another route to meet a temporary requirement, then swap it back again.

Qwest plans to pass along at least some of the cost savings to its customers, says Goel; actual pricing will be revealed as the new services roll out. Goel says that customers also will receive additional service options for the prices they are paying now, including a variety of service levels based on different latency, restoration, and bandwidth-availability parameters.

Goel says Qwest is open to the possibility of extending this new technology to other ventures, including the new KPNQwest pan-European network. However, he says the current focus for the all-optical technology remains on the United States for the present.

Williams Communications (Tulsa, OK) continued its move toward optical networking with the announcement that it will purchase the MultiWave CoreDirector from CIENA Corp. (Linthicum, MD). The value of the three-year deal could be as great as $40 million. The carrier also announced a field trial of the CorWave optical-networking product line from Corvis (see accompanying story for details of this equipment).

The CoreDirector was developed by Lightera Networks, which CIENA purchased last March. The optical core-network switching device offers 640 Gbits/sec of full-duplex switching. The initial release of the product will support 256 OC-48/STM-16 or 64 OC-192/STM-64 interfaces in a single bay. It will switch at the wavelength level or to channelized STS-N granularity down to STS-1. The device supports simultaneous ring, linear line, and path-level mesh protection.

"CoreDirector will provide the high-bandwidth switching, protection, and provisioning capabilities for our next-generation optical network, making it possible for us to offer our carrier customers switched optical services ranging from wavelengths to protected private-line services," Greg Floerke, vice president of engineering and construction for the Williams network, said in a prepared statement offered as part of the contract announcement.

Trials and certification of the CoreDirector are expected to be completed by early this year, with actual purchase and deployment following over the three-year period of the contract.

Meanwhile, the field trials of the Corvis products will begin early this year. Williams will test the equipment over a route that runs from Houston to Herndon, VA, via Atlanta. Additional routes will be announced during the first quarter of this year. If successful, Williams may begin commercial deployment of the Corvis equipment in other parts of the network in the second half of this year.

The trial will see initial capacities of 400 Gbits/sec scale to 2.4 Tbits/sec. The equipment will offer same-day provisioning of high-capacity circuits.

The core-switching purchase follows previous deals with Sycamore Networks (Chelmsford, MA), which includes delivery of the optical startup's recently enhanced SN 8000 Intelligent Optical Network system. The enhancements include long-haul system modules and OC-3/12 service modules, which enables the SN 8000 to serve short-, medium-, and long-haul requirements in a single platform.

It offers 1600-km transmission without electrical regeneration. The modules combine the elements of several box-level systems onto a single card. These elements include Synchronous Optical Network/Synchronous Digital Hierarchy add/drop multiplexing and crossconnect functions, bit-error-rate test capability, and dense wavelength-division multiplexing.