Posted: 07/2000

Qwest, Broadwing to Buy Intelligent Optical
By Charlotte Wolter

Qwest Communications International Inc.
(www.qwest.com) and Broadwing Communications, a wholly owned subsidiary of Broadwing Inc.
(www.broadwing.com), have announced large deployments of intelligent optical technology in their long-haul and metro networks.

They join Williams Communications Inc.
(www.williamscommunications.com), Level 3 Communications Inc.
(www.level3.com) and several European long-haul service providers as members of the small but significant intelligent optical club companies that have deployed DWDM networking technology that includes mesh topologies and intelligent routing of lambdas.

CIENA Corp.
(www.ciena.com) announced that Qwest had signed an agreement to buy CIENA’s MultiWave CoreStream and MultiWave Metro intelligent optical transport system, as well as its MultiWave CoreDirector intelligent optical core switch.

The equipment will be deployed in long-haul and metro networks operated by Qwest. In addition to its national, IP-based fiber optic network, Qwest has initiated a local service, Qwest Local Broadband. For this service, Qwest is building fiber networks in 25 metropolitan areas, including Dallas/Fort Worth, Houston, Kansas City, Los Angeles, New York, St. Louis and Washington D.C.

Similarly, Corvis Corp.
(www.corvis.com) announced that Broadwing will buy $200 million of
Corvis’ optical products for a network that will support 2.5gbps and 10gbps transmission.

The CIENA and Corvis products, and similar products from Sycamore Networks Inc.
(www.sycamorenet.com), provide a new approach to high-capacity long-haul optical networking. In a traditional SONET infrastructure, multiple rings are used to create a large network, such as a national network across the United States with protection against network outages.

In so-called intelligent optical networks, traffic is routed on multiple wavelengths, and a mesh topology with multiple nodes is used to provide protection. Intelligent nodes have the ability to find a new path for waves through the network if there is a fiber cut. They can also reroute traffic if there is network congestion.

The mesh topography approach to optical networking is just beginning to be introduced to the metro arena, where SONET rings have also predominated. Mesh topology, vendors assert, can also help manage traffic and prevent congestion in metropolitan areas. Although metro areas typically enjoy greater fiber resources than long-haul networks, they also face growing capacity demands and less predictable traffic flow.

The Corvis product had several advantages for Broadwing, says Dale Richardson, director of engineering. “One of the nice features about that system is that we can deploy a mesh, ring or linear system because our topology is probably going to entail all of those.”

Chris Rothlis, vice president of engineering, says, “We will test all topologies and initially deploy a ring and eventually a mesh.”

The mesh topology, he adds, needs less redundancy to provide protection than a ring architecture, freeing up more bandwidth
for transport.

Another advantage is the long reach of the Corvis optical transmitters. “It gives ultra-long reach without regeneration,” says Richardson. “In today’s systems, you have to regenerate every 400 km, which is the bulk of the cost over the system’s life. This allows us to go 3,200 km or more without regeneration.”

The long reach will allow Broadwing to exploit the Corvis network’s ability to do “optical routing and wavelength switching without having to break those signals down electrically,” Richardson says. “We will have optical routers that we will deploy at our major

junction points.”

The system’s ability to scale to 1260 OC-192s or 12.6 terabits of capacity is an economic advantage. “That is where the economics come into play that make it worth it to deploy,” Richardson says. “We have had difficulty finding equipment that scales to that range.”

Customer bandwidth demands used to cluster around DS-3s or OC-3s. “Those have now gone to OC-12s and even OC-48s today, and carrier connects OC-48s to OC-192s,” Richardson says. “We are definitely seeing movement upwards in bandwidth requirements, so we have to stay one step ahead of the game, and this is an important piece for us to do that.”