CIENA's MultiWave Metro Selected by Cable & Wireless USA for Nationwide High-Capacity Internet Network Build.

LINTHICUM, Md.--(BUSINESS WIRE)--June 7, 1999--

CIENA Corporation (Nasdaq: CIEN) announced today that Cable & Wireless USA has selected CIENA's MultiWave Metro(TM) dense wavelength division multiplexing (DWDM) optical transport system as a key building block for Cable & Wireless' nationwide, next-generation, high-capacity Internet network. CIENA is expected to begin shipping equipment in July 1999, for the first phase of this project, which is expected to provide intra-city connections for more than 20 metropolitan areas in the United States.

"The next critical bandwidth bottleneck in carrier networks lies in the metropolitan area," said Scott Clavenna, chief analyst at Pioneer Consulting in Cambridge, MA. "Bringing the benefits of optical layer scalability and survivability to this market will greatly improve the competitiveness of carriers that adopt metro DWDM solutions." Clavenna continued, "A deployment of this scale will play a key role in enabling the metro optical networks market, which is forecast to exceed $1 billion by 2003."

During the next two years, Cable & Wireless expects to spend $670 million in order to build a new Internet network connecting more than 60 metropolitan areas across the Untied States. Phase one of the project, connecting approximately 20 to 25 cities, is expected to be completed by the fourth quarter of 1999 with the remaining cities to be connected in 2000.

"Cable & Wireless is committed to providing 100% reliable high-bandwidth services to our metropolitan customers and with CIENA's help, we are building the best Internet network to deliver those services," said Denny Matteucci, chief executive officer of Cable & Wireless USA. "CIENA's optical networking solutions offer enormous flexibility, enabling us to offer our customers multiple voice and data services on the same optical backbone."

"Customers of Cable & Wireless are likely to benefit significantly from this carrier's industry-leading and no-nonsense approach to the challenges of deploying and operating metropolitan networks," said Patrick Nettles, CIENA's president and chief executive officer. "Metro's ability to support a variety of survivable network topologies simultaneously will give Cable & Wireless the flexibility it needs as it builds a next generation network capable of integrating and transporting Internet, data, voice and messaging communications. In addition, Metro's scalable architecture will allow Cable & Wireless to more easily manage network growth in frequently unpredictable metropolitan networks."

The Cable and Wireless urban buildout is believed to be the largest scale metropolitan deployment of DWDM systems to date. Nettles noted that: "This is another indication of CIENA's position as once again being first out of the gate with real-world deployable optical technology, and confirms our vision that an important new opportunity in DWDM networks will be in support of Internet applications in metropolitan environments."

CIENA's MultiWave Metro will be used to connect Cable & Wireless' long-haul network to the short-haul network. MultiWave Metro rings will be used to migrate traffic from the current point-of-presence to Cable & Wireless' new network.

CIENA's MultiWave Metro is a ring-based optical networking transport system using DWDM technology, designed for service provider metropolitan applications. Logically configurable in point-to-point, mesh or ring topologies, MultiWave Metro enables deployment of SONET/SDH, IP, ATM, or private line services with ring, mesh, or point to point logical connectivity.

Metro's ability to drop any wavelength at any location enables the system to support a variety of virtual networks efficiently on a single fiber pair, dramatically increasing a service provider's ability to support both current and future services. The system provides carriers up to 60 Gb/s of voice, data and video traffic over a single fiber pair. CIENA's MultiWave Metro differs from other solutions by being a complete carrier-class solution for a wide variety of protocols, data rates and network survivability options.

ABOUT CIENA

CIENA Corporation's market leading optical networking systems form the core of telecommunications networks worldwide. CIENA's LightWorks(TM) architecture 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 architecture can be found on its worldwide Website: http://www.ciena.com.

NOTE TO INVESTORS:

Forward-looking statements in this release 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 updated and restated into "plain English" format in a Form 8K filed April 5, 1999, and as further updated by the Company's Quarterly Report on Form 10-Q as filed with the Commission on May 21, 1999.