A league of its own?

Sprint's most recent network upgrade activity is a strong indication of why the company tends not to associate itself with any of the labels assigned to the various categories of public network operators.

Just last week, the carrier made early strides into the next generation of networking when it announced a major overhaul designed to push the voice and data capabilities of its long-distance network to local customers as well (see story on page 8). The move strengthened what was already a highly organized view of how Sprint's existing network could be altered and expanded to provide the higher speeds and capacity that data networking demands have created.

Sprint's vision of the network of the future-even before it unveiled its local market attack strategy last week-revealed a fiber core made hearty by wavelength division multiplexing (WDM), reliable by Sonet four-fiber, bidirectional line-switched rings, and pulled together by asynchronous transfer mode switching. Now Sprint plans to leverage multiple technologies in the access network-some wireless, some wireline and some that hinge on the cooperation of local network operators-that will allow it to extend that long-haul backbone to serve customers in the local loop.

The transport portion of Sprint's network has evolved to a highly reliable and scalable fiber backbone, says Marty Kaplan, senior vice president and chief technology officer at Sprint.

"The survivability is there with Sonet, and the scale is there with WDM," Kaplan says. Sprint has a long-standing commitment to ATM as a key component of its switching fabric, and with last week's plan the carrier made a marked move away from traditional circuit-switched architectures. ATM will serve as the integrated switching platform that will help the carrier guarantee quality of service and economic efficiencies, Kaplan says.

"ATM that is in the core today will be pushed to the edge. As things become more efficient, they go to the edge," he says. Sprint's traffic today carries approximately seven times more voice than data traffic, but Kaplan maintains that the carrier would stand by its network construction and expansion strategies even if data were the more dominant driver.

"If I reversed those numbers, my technology and architecture would be the same," he says. "Even if I was 75% data and 25% voice, I would only be paying a very small penalty to run those services over that ATM fabric."

WDM technology is crucial to the carrier's capacity issues because of its ability to carve out additional fiber paths from existing fiber plant.

Sonet technology will begin to play a varied but still crucial role in Sprint's network. The transport technology in its ring architecture will continue to be a part of the carrier's backbone network-Sprint recently deployed its 100th Sonet ring-but it will also be pushed toward the edges of the network and used as an access method, Kaplan says. "You adapt that as the entrance and exit vehicle for all bandwidth demands," he says.

The role of optical networking in Sprint's future network evolution will play an increasingly important role as the carrier begins to implement optical switching methods, Kaplan adds.

"In the future, the transport and switch level demarcs will get cloudier when you get into optical or wavelength switching," he says. "You will have a switching and transport fabric that is going to be blurred.">CNSpecial Re port