RCN CORPORATION SELECTS CIENA'S OPTICAL NETWORKING SYSTEMS TO HELP ACCELERATE COST ADVANTAGE OVER COMPETITORS

Facilities-Based Provider of Phone, Cable and Internet Services Deploys CIENA Gear To Support Internet Growth, Increase Competitive Cost Advantage

Linthicum, MD — 08/17/1999

RCN Corporation (Nasdaq: RCNC) announced today that it has selected Ciena Corporation's (NASDAQ: CIEN) MultiWave Sentry™ dense wavelength division multiplexing (DWDM) optical transport system for deployment in its East Coast fiber backbone. RCN is building a new fiber optic network around the Internet that has the ability to evolve with technology while achieving what RCN believes will be the lowest operating costs of any communications network serving the residential market. Ciena has already received its first $7 million equipment order for a system serving RCN's Boston to Washington, D.C. fiber backbone.

Use of Ciena's MultiWave Sentry system will help RCN maximize the capacity of its most valuable network resource - its fiber optic facilities - by electronically deriving up to 40 wavelength paths over a single fiber strand. This advantage, which increases capacity while preserving RCN's low network operating costs, is critical at a time when service prices are decreasing, and network cost is becoming an increasingly significant factor in calculating the cost of providing service.

"As one of the nation's largest regional Internet service provider (ISP), we look forward to unleashing the significant performance and revenue potential of our advanced fiber optic network, particularly for our rcn.com Internet brand," said Mike Adams, president of RCN's Technology and Network Development Group (TNDG). "Ciena's MultiWave Sentry provides flexible bandwidth capacity that will make it easier to rapidly provision service to our valuable customers, and preserve RCN's status as the low-cost provider in the markets we serve."

RCN is one of the nation's largest single-source, facilities-based providers of bundled communications services to the residential market. In addition to its cable and telephone operations, RCN now provides Internet access to more than half a million Internet customers - nearly all strategically targeted in the Boston to Washington, D.C. corridor.

"The Ciena MultiWave Sentry looks to be a great strategic fit for RCN. RCN has the unique ability to add new services while maintaining its low operating costs, and Sentry's open architecture allows the company to accommodate new technologies and offer new services," noted Charles Chi, marketing vice president at Ciena. "RCN can also cost effectively access wavelengths at an OC-48 rate in numerous metropolitan locations without terminating the entire 40 channels, which is critical on routes within the congested Northeast corridor."

About the RCN Network

RCN's True Local Network™ is a unique broadband fiber optic platform capable of offering a full suite of communications services--including fully-featured voice, video and high-speed Internet--to residential customers. The network employs SONET ring backbone architecture, and localized nodes built to ensure RCN's state-of-the-art fiber optics travel to within 900 feet of RCN customers, with fewer electronics and lower maintenance costs than existing local networks. RCN's East and West Coast local fiber optic networks target densely populated areas comprising nearly 40% of the U.S. residential communications market spread over just 6% of its geography.


About Ciena

Ciena Corporation's market-leading intelligent optical networking systems form the core for the new era of telecommunications networks. Ciena's LightWorks™ architecture changes the fundamental economics of service provider networks by simplifying the network architecture and reducing the cost to operate it. Additional information about Ciena can be found on its worldwide Website: http://www.ciena.com
About RCN Corporation
RCN Corporation (Nasdaq: RCNC) is the nation's first and largest single-source, facilities-based provider of bundled communications services to the residential market, and the nation's largest targeted Internet service provider (ISP), with all of its 500,000+ customers strategically clustered in the Boston to Washington and San Francisco to San Diego corridors. The company is currently providing local and long distance phone, cable television and its rcn.com Internet services to the densest telecommunications markets in the country, from Boston to Washington, D.C. in the East and San Francisco to San Diego in the West.
Press Contacts:
Nicole Anderson
Ciena Corporation
(877) 857 -7377
pr@ciena.com Jim Maiella
RCN Corporation
Public Relations
(212) 842-7880
Investor Contacts:
Marie Downing
Ciena Corporation
(888) 243-6223
ir@ciena.com Valerie Haertel
RCN Corporation
Investor Relations
(609) 734-3816