Press Release

CIENA ENHANCES BROADBAND SERVICE DELIVERY FOR SPAIN'S ARSYS INTERNET WITH LAUREL NETWORKS B-RAS SOLUTION

CIENA-Laurel Partnership Supports Rapid Growth of Spanish ISP Customer Base

HANNOVER, Germany - March 18, 2004— At CeBIT 2004, CIENA Corporation (NASDAQ: CIEN), a global provider of innovative network solutions, today announced that Arsys Internet S.L., a leading Internet Service Provider (ISP) in Spain, selected CIENA to supply a next-generation Broadband Remote Access Server
(B-RAS) solution for its growing network. Through its strategic relationship with Laurel Networks, CIENA will provide Laurel's ST200™ Service Edge Router to resolve Arsys' challenge of economically scaling to meet its aggressive growth plans for the delivery of broadband services.

After engaging several B-RAS vendors in extensive technology evaluations, Arsys selected CIENA to provide the Laurel Networks ST200 platform to meet rapid subscriber growth and customer demand for higher connection speeds. With support for an
industry-leading 128,000 subscriber sessions per chassis, the ST200 will enable Arsys to provide its customers high-bandwidth services while lowering the average cost per session.

"CIENA emerged as the most suitable vendor to provide the high subscriber session support required to overcome Arsys' primary obstacle of cost-effectively supporting a demand for high session counts and high bandwidth per session," said Rafael Citoler, General Director at Arsys Internet, S.L. "In addition to reducing our cost per connection, the ST200 also enables exceptional Quality of Service and carrier-class stability, so we can be confident that our guarantee to customers of service availability and bandwidth allocation is upheld. The combined solution, CIENA's local presence and Laurel's platform, creates a complete service portfolio for us to increase the efficiency and profitability of our network and cost-effectively attract new customers."

As Arsys continues to evolve its network for the future, the Laurel
B-RAS solution allows for additional sophisticated broadband services for businesses, including VPNs (Virtual Private Networks) and VPLS (Virtual Private LAN Services) over broadband access, to be simply turned on via software. And, for Arsys' consumer customers, the ST200 includes the high bandwidth-per-subscriber, advanced QoS and integrated routing and switching required to offer triple play services including voice, video and data over a single connection.

"The ST200 B-RAS solution will help Arsys launch new high-value broadband services and facilitate the creation of integrated IP and Internet-based services for business customers, in addition to affording critical scalability features," said Nick Jeffery, senior vice president of worldwide sales at CIENA. "Demonstrating our flexibility and responsiveness as we diversify our portfolio, CIENA delivered the ST200 B-RAS solution to Arsys less than one month after design customization began, helping to quickly increase Arsys' position as a vanguard ISP in its area of operation."

Jeffery added: "This customer win is evidence of the successful partnership between CIENA and Laurel Networks. Integrating the Laurel platform into the CIENA portfolio is further enabling networks, like Arsys', to better capitalize on the profit potential of data and broadband services. By extending our reach into Layer 3 edge routing, Laurel's ST200 brings additional value to CIENA's comprehensive, next-generation networking solution, and reinforces our commitment to improve the economics of network ownership and provide value to our customers."

ST200 B-RAS Solution
The ST200 is dramatically more scalable than existing B-RAS devices, enabling broadband service providers to cost-efficiently evolve beyond basic Internet service to sophisticated services that can immediately begin impacting revenues such as IP VPNs and multimedia content delivery over broadband access networks. Only the ST200 B-RAS includes the high bandwidth-per-subscriber, advanced QoS, carrier-class availability and integrated routing and switching required for complete and reliable broadband service delivery. Unlike solutions that require service-specific line cards, ST200 B-RAS functionality is implemented in its ShadeTree™ System Software, enabling B-RAS support on any card installed on the ST200 platform with no additional hardware required.

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.

About Laurel Networks
Laurel Networks is leading the creation of The New Service Delivery Architecture to enable profitable delivery of data and IP services at the edge of carrier IP/MPLS networks. Laurel's service edge routers and service management software are evolving carrier architectures from multiple data networks to a single packet-switched architecture with minimal capital investment. Combining carrier-class routing, data switching, advanced QoS and high availability, Laurel service edge routers support both routed and switched services. This unmatched service agility allows carriers to evolve their service portfolio to meet changing market requirements. Laurel Networks was founded in 1999 and is headquartered in Pittsburgh, Pennsylvania. For more information, visit www.laurelnetworks.com.

Notes 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.

Press enquiries:
CIENA: Denny Bilter or Aaron Graham
CIENA Corporation
tel: (877) 857-7377
pr@ciena.com

Laurel Networks: Kimberly Booth
Laurel Networks, Inc.
tel: 412-809-4298
email: kbooth@laurelnetwoks.com

Investor Contacts:
CIENA: Suzanne DuLong or Jessica Towns
CIENA Corporation
tel: (888) 243-6223
ir@ciena.com