Diversity rules

Bell Atlantic's recently announced plans to upgrade its networks is a prime example of how a multitechnology evolutionary strategy can be applied to a legacy network. In March, the Bell company announced that it would buy $240 million in switching equipment and software from Northern Telecom to help diversify its service capabilities. The deal included processor upgrades for the Nortel DMS SuperNode switches the carrier already has in place, as well as DMS Enhanced Networks and primary rate ISDN hardware and software.

But the bulk of the deal came a week later, when Bell Atlantic unveiled the details of a $1.5 billion upgrade plan that encompasses multiple vendors-Lucent Technologies, Ciena, Fujitsu, DSC Communications and Tellabs among them-and multiple technologies. One of the more noteworthy components of that strategy is the fact that the carrier will be one of the early local network operators to turn to wavelength division multiplexing technology as a way to upgrade its existing fiber plant.

"If you're really trying to increase the capacity of a fiber route, you have the choice to put traffic on another fiber or to start multiplexing," says Ray Albers, vice president of network architecture at Bell Atlantic.

Bell Atlantic will also continue its allegiance to Sonet transport systems, Albers says, partly because of the reliability of the format. "The ring architecture makes protection switching a lot simpler to do," he says.

Part of the carrier's mission is to enhance the optical capabilities of its networks and eliminate some of the optical-to-electrical-to-optical conversions required over its Sonet rings-conversions that can drag down transport speeds and reduce capacity. "In a few years we'll be able to eliminate some of those steps," Albers says.

As for the access network, Bell Atlantic announced just last week that it would begin deploying ADSL in several mid-Atlantic markets beginning in September (see story on page 14).