BellSouth Awards DWDM Contract to CIENA for Long-Haul Interoffice Facility Relief.

LINTHICUM, Md.--(BUSINESS WIRE)--May 17, 1999--

CIENA's MultiWave Sentry(tm) Initially Deployed In Five States

BellSouth today announced that it has contracted with CIENA Corporation (Nasdaq: CIEN) to supply the MultiWave Sentry(tm) dense wavelength division multiplexing (DWDM) optical transport system for long-haul interoffice facility relief in its network. Initial deployments of CIENA's equipment, which started in January, already cover five states including Georgia, Alabama, Mississippi, North Carolina and Florida.

"Deploying CIENA's MultiWave Sentry provides immediate bandwidth relief in BellSouth's long-haul interoffice facilities (covering distances of 15 miles or more) and gives us a scalable, flexible platform for network growth and service delivery," said Dr. David Kettler, vice president - BellSouth Science and Technology.

Kettler indicated that BellSouth expects to deploy more CIENA DWDM systems during 1999 "in order to provide the increasing bandwidth requirements our customers demand while reducing capital outlays for fiber reinforcement." He also said DWDM technology enables BellSouth to reduce provisioning time associated with additional network capacity.

"While BellSouth's initial deployment of DWDM will be focused on opening bandwidth-constrained pipes, economic benefits and network scalability also are important features of CIENA's MultiWave Sentry," said George Peabody, managing director of telecommunications research at the Aberdeen Group. "Given its stringent testing process, BellSouth's choice sends a strong message to other RBOCs and CLECs about CIENA's performance and reliability. Down the line, CIENA's vision of an intelligent optical network and its LightWorks Initiative(tm) will have network-wide implications."

"As one of the first RBOC's to deploy optical transport, BellSouth is clearly running at the forefront," said Patrick Nettles, CIENA's president and chief executive officer. "Through its ability to simultaneously support multiple traffic types and transmission rates, CIENA's MultiWave Sentry maximizes the performance capabilities of BellSouth's existing network infrastructure and enables enhanced high-bandwidth service offerings required by customers."

About BELLSOUTH

BellSouth (NYSE: BLS) is a $23 billion communications services company. It provides telecommunications, wireless communications, cable and digital TV, directory advertising and publishing, and Internet and data services to nearly 34 million customers in 19 countries worldwide. In the U. S., BellSouth provides telecommunications services in nine Southeastern states, including Alabama, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina and Tennessee. With its headquarters in Atlanta, BellSouth serves more than 24 million local telephone lines and provides local exchange and intraLATA long distance service over one of the most modern telecommunications networks in the world. More information on BellSouth is available on the World Wide Web at http://www.bellsouth.com.

About CIENA

CIENA Corporation's market leading optical networking systems form the core of telecommunications networks worldwide. CIENA's LightWorks(tm) Initiative changes the fundamental economics of service provider networks by simplifying the network architecture and reducing the cost to operate it. CIENA's networking solutions utilize bandwidth expanding dense wavelength division multiplexing (DWDM) technology and include the MultiWave(R) family of products for long-haul, short-haul and metropolitan applications. CIENA's CoreDirector(tm), an intelligent optical core switch, delivers dynamic provisioning, grooming, flexible capacity management and survivability. Through its CIENA Services subsidiary, CIENA provides a range of engineering, furnishing and installation (EF&I) services for telecommunications service providers in the areas of transport, switching and wireless communications.

Additional information about CIENA and its LightWorks Initiative can be found on its worldwide Website: http://www.ciena.com.

NOTE TO INVESTORS:

Forward-looking statements in this release, including those referring to network-wide implications of CIENA's vision and of its LightWorks Initiative, are based on information available to the Company as of the date hereof. The Company's actual results could differ materially from those stated or implied in such forward-looking statements, due to risks and uncertainties associated with the Company's business, which include difficulty in anticipating core demand for bandwidth as well as other risk factors disclosed in the Company's Annual Report on Form 10-K, as filed with the Securities and Exchange Commission on December 9, 1998, as supplemented by the Company's Quarterly Report on Form 10-Q as filed with the Commission on February 18, 1999, and as updated and restated into "plain English" format in a Form 8K filed April 5, 1999.