CIENA to Help Build Next-Generation Network For MCI.

Business Editors/High-Tech Writers

LINTHICUM, Md.--(BUSINESS WIRE)--Feb. 23, 2004

CIENA's CoreStream Platform To Support Industry's Most Extensive Ultra Long-Haul Network With Integrated Optical Transport and Switching Solutions

CIENA(R) Corporation (NASDAQ:CIEN), a leading global provider of innovative network solutions, today announced that MCI (WCOEQ, MCWEQ) has selected CIENA as a strategic supplier for its new nationwide, ultra long-haul (ULH) network. As MCI converges its legacy networks to deliver voice and data services over a single next-generation infrastructure, the company will deploy CIENA's CoreStream(TM) platform for integrated optical transport and switching.

CIENA is helping MCI build an efficient infrastructure to allow the migration of all types of customer traffic - from voice to IP/MPLS - onto a cohesive and automated network that extends coast to coast. CoreStream will provide a reliable optical ULH backbone that integrates software-configurable wavelength switching. CoreStream's ultra long-haul capabilities will allow MCI to eliminate costly electrical signal regenerations, while automated wavelength switching will allow MCI to remotely provision wavelengths.

"MCI's next-generation network will offer a rich array of new technology and features that focus on driving down operating costs while providing customers with future communication services," said Fred Briggs, MCI president of operations and technology. "This is not merely a network overbuild. We are working to roll out the industry's newest, most advanced network. CIENA understands our convergence networking strategy and offers the latest generation multiservice solutions that will help ensure MCI's converged network is the most robust and resilient communication resource for our customers."

CIENA President and CEO Gary Smith said, "MCI is moving to deploy the industry's most extensive all-service, ultra long-haul network. No major carrier has undertaken such a comprehensive effort, building an entirely new network designed specifically to offer the highest levels of efficiency and reliability for the broadest range of voice and data services. We're pleased that MCI recognizes the economic and competitive value in CIENA's solution for converged networks, and we're proud to serve such a crucial role in MCI's network evolution."

By merging its software-driven optical portfolio with new-generation data networking capabilities, CIENA is enabling service providers like MCI to converge multiple voice and data networks onto a single automated, all-service infrastructure. This strategy for network convergence delivers the carrier-class reliability of circuit-based networks and the service-adaptability of packet-based networks - all under unified control.

CIENA's CoreStream Optical Transport & Switching Platform

CIENA's newest generation CoreStream is designed as a single-platform optical transport and switching solution, providing:

-- Reconfigurable wavelength switching, allowing MCI to adapt its

network to changing traffic demands via software while

providing all-optical connectivity at high-capacity network

nodes.

-- Both 25GHz and 50GHz channel spacing within one system,

allowing MCI to optimize its network for both capacity and

distance all within the C-band. CIENA provides the industry's

most efficient use of optical bandwidth, accommodating larger

channel counts with fewer amplifiers.

-- High-performance amplifiers with dynamic gain flattening for

ULH applications, allowing un-regenerated signal propagation

of 3,200 km and beyond while reducing network costs by

minimizing the number of OEO (optical-electrical-optical)

conversions.

-- Tunable lasers, standard in CoreStream's 10G transceivers, to

reduce network capital and operating costs by streamlining

laser hardware, simplifying management with remote dynamic

provisioning, and dramatically lowering maintenance and

sparing requirements.

-- LightWorks OS(TM) software to reduce the need for manual

intervention by enabling automated network reconfiguration and

remote rerouting of signals - eliminating truck-rolls when the

system configuration is changed.

"As part of our ongoing LightWorks Services portfolio evolution strategy, we are integrating next-generation functionality and data interfaces into the CoreStream system, which helps drive network efficiency for service providers such as MCI while delivering the service convergence their customers want and need," said Francois Locoh-Donou, CIENA's vice president of marketing.

Service providers may choose any combination of features to customize the CoreStream platform, applying only the technologies required for specific applications and network nodes. This approach helps keep costs down while enabling service providers to rely on one platform for the delivery of carrier-class data and voice services across the entire network.

ABOUT CIENA

CIENA Corporation delivers innovative network solutions to the world's largest service providers and enterprises, increasing the cost-efficiency of current services while enabling the creation of new carrier-class data services built upon the existing network infrastructure. Additional information about CIENA can be found at www.ciena.com.

NOTE TO INVESTORS

This press release contains certain forward-looking statements based on current expectations, forecasts and assumptions of CIENA (the Company) that involve risks and uncertainties. Forward-looking statements in this release, including but not limited to the features and benefits of CIENA's products, 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 the risk factors disclosed in the Company's Report on Form 10-Q filed with the Securities and Exchange Commission on February 19, 2004. Forward-looking statements include statements regarding the Company's expectations, beliefs, intentions or strategies regarding the future and can be identified by forward-looking words such as "anticipate," "believe," "could," "estimate," "expect," "intend," "may," "should," "will," and "would" or similar words. The Company assumes no obligation to update the information included in this press release, whether as a result of new information, future events or otherwise.