Ciena Achieves Milestone with CNX-5 Broadband DSL System; More Than 18,000 CNX-5 Systems Shipped with Capacity to Serve More Than 2.5 Million Homes.

LINTHICUM, Md. -- Ciena(R) Corporation (Nasdaq:CIEN), the network specialist, today announced it achieved an important milestone with its CNX-5(TM) Broadband DSL System. With more than 18,000 systems shipped since 2001, Ciena's CNX-5 currently supports capacity to serve more than 2.5 million homes with broadband services. This milestone coupled with quarter over quarter shipment growth the first two fiscal quarters of 2005 indicates that Ciena's CNX-5 system is the most widely deployed legacy DLC upgrade in North America and affirms Ciena's role as a key broadband solutions provider.

Designed to DSL-enable the more than 17 million phone lines connected by Lucent's SLC(R) Series 5 (SLC-5) Digital Loop Carriers (DLC), Ciena's CNX-5 offers service providers a simple line card replacement to deploy DSL services from their existing network infrastructure without reducing plain old telephone service (POTS) port density. Since its introduction in 2001, the product has been a catalyst in helping to expand all four RBOCs' DSL customer bases throughout North America by enabling enhanced service offerings. Additionally, the CNX-5 system helps address the broadband divide that exists between metro and suburban areas by extending DSL services beyond Central Office DSLAM locations.

Ciena's unique SLC-5 upgrade kit not only simplifies the delivery of DSL services, but also offers significant CAPEX and OPEX savings when compared to alternative overlay solutions. The simplicity of the CNX-5 system allows service providers to economically deploy DSL services at an attractive price point to better attract dial-up subscribers to upgrade their service. With DSL currently outpacing cable and dial-up access technologies, evidenced by the DSL Forum's estimates of 41.5 percent growth in subscribers in Q4'04, DSL upgrades continue to be a viable and lucrative market.

"Service providers are in a challenging phase right now as they look to find a balance between reducing operating and capital expenditures while also delivering the value-added services demanded by their customers," said Ron Westfall, principal analyst of broadband infrastructure, Current Analysis. "Ciena's CNX-5 has proven a valuable system in aiding the RBOCs at balancing out expenses in the delivery of cost-effective DSL services, while also enabling them to bring on new customers who migrate from dial-up services."

Ciena recently enhanced the CNX-5 by introducing a standards-compliant ADSL2+ Enhanced Channel Unit (ECU) to deliver downstream data rates of up to 24 Mbps for bandwidth-hungry applications. In addition, Ciena added a Symmetric Channel Unit (SCU) supporting two standards-compliant SHDSL ports to deliver symmetric data rates of 2.3 Mbps to support the high-speed upstream needs of advanced business applications.

Some of the unique features of the simple and cost-effective CNX-5 solution include:

--Requires no costly additional remote terminal infrastructure (i.e. no adjunct cabinets, pads or POTS splitters);

--Offers a plug-and-play DSL upgrade with minimal technician training;

--Supports both T1 copper-fed and fiber-fed SLC-5s to broaden network deployments, utilizing a fiber ring to aggregate traffic from multiple CNX-5s onto a single DS3 interface;

--Offers enhanced network management including an Historical Statistics Collector, which collects performance monitoring and subscriber metrics for improved customer support and network planning;

--Managed by an OSMINE-compliant Element Management System (EMS) that provides seamless integration into northbound NMS and OSS legacy systems to achieve true DSL flow-through provisioning.

"As service providers continue to court dial up subscribers to upgrade their services, and push DSL into historically underserved areas, Ciena's CNX-5 offers an unrivalled solution to grow their addressable market while protecting existing investments," said Malcolm Loro, director of product marketing for Ciena's Broadband Access Group. "As demonstrated by this milestone, Ciena's CNX-5 is helping service providers meet the seemingly insatiable customer demand for broadband and the recent addition of ADSL2+ interfaces for advanced data and IPTV applications only expands the platform's versatility."

For more information on Ciena's CNX-5 Broadband DSL System and other broadband access solutions, please visit Ciena at SUPERCOMM 2005 (Booth #22039), which is being held June 6-9 at McCormick Place in Chicago.

ABOUT CIENA

Ciena Corporation is the network specialist, focused on expanding the possibilities for its customers' networks while reducing their cost of ownership. The company's systems, software and services target and cure specific network pain points so that telcos, cable operators, governments and enterprises can best exploit the new applications that are driving their businesses forward. For more information, visit www.ciena.com.

NOTE TO INVESTORS

This press release contains certain forward-looking statements based on current expectations, forecasts and assumptions that involve risks and uncertainties. These statements are based on information available to the Company as of the date hereof; and Ciena's actual results could differ materially from those stated or implied, due to risks and uncertainties associated with its business, which include the risk factors disclosed in its Report on Form 10-Q, which Ciena filed with the Securities and Exchange Commission on June 2, 2005. Forward-looking statements include statements regarding Ciena'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. Ciena assumes no obligation to update the information included in this press release, whether as a result of new information, future events or otherwise.