Cabletron Systems Once Again Leads the Modular Layer 3 Switching Market According to Dell'Oro Group.

Business/Technology Editors

ROCHESTER, N.H.--(BUSINESS WIRE)--Nov. 16, 2000

Subsidiaries Enterasys Networks(TM) and Riverstone Networks 

Achieve The Number One Position In Total Modular Layer 3 Port

Shipments Worldwide

Cabletron Systems (NYSE: CS) today announced that for the seventh consecutive quarter, the Dell'Oro Group has ranked Cabletron number one in market share in the rapidly growing modular Layer 3 switching market. According to the Dell'Oro Group's third quarter report, Cabletron held the number one position in worldwide modular Layer 3 ports shipped, with 29.6% of the market.

The Dell'Oro Group report, issued today, finds that Cabletron ranks number one in market share for the period July through September, 2000 in several categories, including:

--Total worldwide ports shipped, Layer 3 modular (29.6%)

--Total North American ports shipped, Layer 3 modular (29.5%)

--10/100 Ethernet worldwide ports shipped, Layer 3 modular (31.0%)

--10/100 Ethernet North American ports shipped, Layer 3 modular (30.6%)

--Total WAN ports shipped, Layer 3 (91.5%)

The "Q3 Shared Hub and LAN Switch Report" ranks all manufacturers in the Layer 3 switch market, including 3Com, Cabletron Systems, Cisco Systems, Extreme Networks, Lucent Technologies and Nortel Networks. The Dell'Oro Group predicts that the Layer 3 market will grow to $9.4 billion by 2004.

"Cabletron is excited that Enterasys Networks and Riverstone Networks have continued a leadership position in the Layer 3 switching market," said Piyush Patel, CEO and president of Cabletron Systems. "This market leadership demonstrates the strength of Cabletron's new subsidiary companies in the Layer 3 market, as well as the ability of Enterasys and Riverstone to penetrate their target markets with these solutions and provide excellent service to their respective customers."

The SmartSwitch Router family is the industry's highest performing, most reliable line of multilayer switch routers, delivering more than 90 million packets per second (pps) of routed throughput and full-function, wire-speed IP and IPX routing and switching. The SmartSwitch Router is the only Layer 3 switching solution that offers full-function WAN connectivity, eliminating the need for software-based routers.

About Cabletron Systems

Cabletron Systems is a holding company for four of the most innovative, customer-focused organizations in the telecommunications and networking industry:

Enterasys Networks is the only provider of total network solutions singularly focused on enterprise-class customers. By optimizing enterprise network solutions for e-business applications, and by providing global 24 x 7 service and support, Enterasys provides competitive advantage through IT infrastructure to enterprise customers.

Riverstone Networks is the leading developer of routers and switches that enable metropolitan service providers, Internet service providers, and content and application providers to turn raw bandwidth into profitable services. Leveraging third-generation custom silicon and Internet-hardened routing software, Riverstone products deliver line-rate accountability and control, enabling the metro network to become the New Business Internet. Riverstone solutions are deployed in more than 40 countries and some of the world's largest networks - including British Telecom, Genuity, MCI Worldcom, MAE West Ames, Earthlink and Telefonica.

GlobalNetwork Technology Services (GNTS) is one of the largest independent network consulting firms in the world. With consultants in more than 66 locations spanning the globe, GNTS provides network infrastructure solutions that optimize application availability and performance to enterprise and service provider clients.

Aprisma Management Technologies is the leading provider of intuitive multivendor management solutions that meet the service-level requirements of enterprise and service provider customers. Aprisma pioneered the field of intelligent network management in 1990 with the introduction of its flagship SPECTRUM software suite.

With support for a rapidly growing list of over 500 products from the industry's leading network and telecommunications vendors, Aprisma is at the forefront in integrated network and service-level management.

Listed on the New York Stock Exchange for more than a decade under the symbol CS, Cabletron is an S&P 500 index company. Cabletron's web site can be reached on the Internet at www.cabletron.com.