CIENA SUPPLIES LIGHTWORKS SOLUTIONS TO IRELAND'S ESAT TELECOM, FURTHER EXPANDING EUROPEAN PRESENCE

Esat Telecom, CIENA To Connect Ireland And UK With All-Optical Transport Systems

Linthicum, MD — 02/10/2000

Ciena Corporation (CIEN) today announced that it is supplying intelligent optical transport solutions to Irish telecommunications carrier Esat Telecom (Nasdaq/Easdaq: ESAT; ISE: ESAT.I), further expanding Ciena's growing base of European customers. Under the agreement with Esat, Ciena will provide systems from its LightWorks™ suite of intelligent optical solutions for deployment in network spans connecting Ireland to the UK.

At nearly 260 km long, the companies believe that Esat Telecom's cable links between Ireland and the UK represent some of the longest unamplified multi-channel optical fiber spans in commercial deployment. Ciena's extended-reach optical technologies make it possible to network optical systems located in Ireland and the UK without intervening amplification and regeneration.

"We're building a state-of-the-art infrastructure to take on the booming wholesale and ISP markets in Ireland and the UK, and our goals for establishing market share are very aggressive. Broadband connections that can be turned on fast are instrumental," said Nic Stirk, Director of Engineering at Esat Telecom. "Ciena can quickly deliver the high-bandwidth solutions for the applications we need, and we like the intelligence and value that Ciena brings to the network."

"This deployment is particularly important to Ciena. It represents further development of our European operations and a significant entry into the growing Irish market," said Patrick Nettles, Ciena's president and CEO. "Our comprehensive suite of carrier-class intelligent optical networking solutions gave us an edge in winning this key project. Ciena's ability to quickly extend LightWorks solutions to support long unamplified network spans further rounds out our networking portfolio and is further evidence of our leadership in the industry."

Ciena's optical transport solutions are a key element of Ciena LightWorks, a comprehensive blueprint for building intelligent optical networks. With this next-generation architecture, Ciena enables carriers around the world to rapidly transition to dramatically simpler yet higher capacity networks while achieving greatly reduced equipment and operating costs. Ciena's recently unveiled LightWorks Toolkit™ offers technologies to help carriers build and deliver differentiating dynamic optical services.


About Ciena

Ciena Corporation's market-leading optical networking systems form the core for the new era of telecommunications networks worldwide. Ciena's LightWorks™ architecture changes the fundamental economics of service-provider networks by simplifying the network and reducing the cost to operate it. Additional information about Ciena can be found at www.ciena.com.
About ESAT TELECOM
Esat Telecom Group plc comprises business telecommunications company, Esat Telecom, corporate Internet Service Provider, Esat Net, networking systems integration company, BridgeCom Group as well as 49.5per cent of GSM mobile phone operator, Esat Digifone. Esat Clear, a division of Esat Telecom, provides home phone and Internet services to the residential market. The Group is also the official National Partner of Global One in Ireland. During 1999, the Group acquired the data and Internet services provider, PostGEM and its wholly owned subsidiary, Ireland-On Line and the systems integration companies, Viewpoint DataComms and the Kedington Group. It also took a 51per cent shareholding in Labyrinth, an award winning Irish eBusiness company. Esat Telecom Group plc is subject to a recommended cash offer by BT Hawthorn Limited, a wholly owned subsidiary of British Telecommunications plc. For more details on Esat Telecom, visit the website: www.esat.ie
Note to Investors
Forward-looking statements in this release, including, but not limited to, the cost, deployment and network management benefits of the Company'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 10K filed with the Securities and Exchange Commission on December 10, 1999.
Press Contacts:
Nicole Anderson
Ciena Corporation
(877) 857 -7377
pr@ciena.com
Investor Contacts:
Marie Downing
Ciena Corporation
(888) 243-6223
ir@ciena.com