News Release

Rhythms Announces Enhanced National Backbone

With Cisco, MCI WorldCom and Qwest, Rhythms' U.S.
May 25, 1999

With Cisco, MCI WorldCom and Qwest, Rhythms' U.S. LANHigh-Performance Network Capable of Enterprise-Class Demands

ENGLEWOOD, Colo. -- May 25, 1999 -- Rhythms NetConnections Inc. (Nasdaq: RTHM), a leading provider of DSL-based, high-performance networking solutions for remote access to private networks and the Internet, today announced expansion of its nationwide backbone that supports both ATM transport and IP networking. Rhythms will implement Cisco's world-class BPX. 8650 IP+ATM switching platform and strategic partner MCI WorldCom's local-to-global network services, including primary ATM, frame relay, and SONET private line metro area network connectivity. In addition, Qwest will provide frame relay and ATM-based, fiber-optic transport services. Rhythms will combine its DSL network with these companies' innovations to create a nationwide backbone capable of business-class, simultaneous data, voice and video services.

By the end of summer 1999, Rhythms also will offer a family of products and services under the Rhythms U.S. LANT brand name that will allow enterprise and service provider customers to exploit the benefits of the high-speed connectivity and simultaneous multimedia transport that Rhythms' backbone offers. These advantages include increased productivity, significant reduction in cost of services and network management, as well as extended network reach. The services will be made available through Rhythms, Internet Service Providers (ISPs) and network integrators.

"Rhythms' U.S. LAN gives corporations a single-point source for high-speed, managed network connections from remote workers, to branch offices, to headquarters," said Jim Greenberg, Chief Network Officer at Rhythms. "Working with Cisco, MCI WorldCom and Qwest, our customers can enjoy the same services at home and in remote offices that traditionally were only provided within the walls of the corporate headquarters. Rhythms provides a full suite of productivity enhancing applications, coupled with a desktop-to-desktop service management model, all at a fraction of the cost and hassle now associated with remote network management."

The Rhythms U.S. LAN offering includes full deployment of Cisco DSL equipment, including the Cisco 6400 universal access concentrators, Cisco 6100 DSL access concentrators, and Cisco 675 SOHO/telecommuter routers throughout the Rhythms network, to enable seamless integration between the local loop and wide area network and offer superior scalability. Rhythms' U.S. LAN will also use ground-breaking technology such as the Cisco BPX 8650, the first solution in the industry to incorporate a carrier-class implementation of Multiprotocol Label Switching (MPLS), an emerging Internet Engineering Task Force standard based on Cisco's Tag Switching. Cisco's unique approach of combining MPLS with open-standard routing protocols eliminates the need for tunneling and encryption in building virtual private networks (VPNs). This combination significantly reduces complexity, increases scalability and enables end-to-end QoS for business IP applications and services such as voice over IP (VOIP). Cisco's MPLS-based IP+ATM solution will also enable Rhythms to create a highly scalable network, eliminating the scalability limits imposed on networks based only on ATM. With the BPX 8650 and additional Cisco DSL technology, the Rhythms U.S. backbone will be a fully meshed, fault-tolerant, and fully redundant high-speed solution.

"Rhythms' expertise in network engineering and creative use of new high-speed local access technologies results in innovative, affordable managed services for business customers who are information-intensive," said Kevin Kennedy, Cisco senior vice president of the service provider line of business. "Rhythms' nationwide IP+ATM and DSL network brings services and capabilities to a much wider range of customers - and a competitive advantage to Rhythms."

Forrester Research predicts that DSL will capture 10 percent of all enterprise circuits and 12 percent of all home business circuits by 20031. Only Rhythms offers productivity applications based on DSL connectivity, such as PBXpressd, a PBX extension capability for remote workers, Virtual Private Network (VPN) creation, and Network Nowd, a self-service tool for customers to select and monitor their network performance and status.

"Rhythms is leveraging MCI WorldCom's industry-leading network infrastructure to deliver a variety of carrier-class DSL services," said Brian Brewer, MCI WorldCom senior vice president of business product marketing. "MCI WorldCom is leveraging Rhythms' DSL technology deployment to extend the reach of our on-net services and deliver a wide range of enterprise-wide networking applications through a single, integrated DSL access line."

"Qwest shares a commitment to deliver end-to-end high-speed connectivity and managed services with Rhythms to customers," said Larry A. Seese, executive vice president of network engineering and operations for Qwest. "The combination of our state-of-the-art network, which is designed for Internet communications, with Rhythms' last-mile solution, will help drive the creation and adoption of high-end broadband communications services."

Rhythms provides managed network services for business users, based on "always on," high-speed DSL access via local connections ranging in speeds from 128 kbps to 7.1 Mbps (approximately 125 times the speed of today's fastest dial-up modem). Pricing for customers is based on integrated pricing for leased, fully-managed networks and includes configuration, installation, equipment and network management. Because the Rhythms network design requires no equipment purchase by the user and optimizes both local and wide area network capacities, the acquisition price for customers is generally 30 to 50 percent less than other high-speed services.

About MCI WorldCom

MCI WorldCom is a global leader in communications services with 1998 revenues of more than $30 billion and established operations in over 65 countries encompassing the Americas, Europe and the Asia-Pacific regions. MCI WorldCom is a premier provider of facilities-based and fully integrated local, long distance, international and Internet services. MCI WorldCom's global networks, including its state-of-the-art pan-European network and transoceanic cable systems, provide end-to-end high-capacity connectivity to more than 40,000 buildings worldwide. MCI WorldCom is traded on NASDAQ under WCOM. For more information on MCI WorldCom, visit the World Wide Web at

About Qwest

Qwest Communications International Inc. (NASDAQ: QWST) is a leader in reliable and secure broadband Internet-based data, voice and image communications for businesses and consumers. Headquartered in Denver, Qwest has more than 8,500 employees working in North America, Europe and Mexico. The Qwest Macro Capacity. Fiber Network, designed with the newest optical networking, will span more than 18,500 route miles in the United States when it is completed by mid-1999, and an additional 315-mile network route that will be completed by the end of the year. In addition, Qwest and KPN, the Dutch telecommunications company, have formed a venture to build and operate a high-capacity Europan fiber optic, Internet Protocol-based network that has 2,100 miles and will span 9,100 miles when it is completed in 2001. Qwest also has nearly completed a 1,400-mile network in Mexico. For more information, please visit the Qwest web site at

About Rhythms

Rhythms NetConnections Inc. is an Englewood, Colorado-based business with commercial services in San Diego, San Francisco, Oakland/East Bay, San Jose, Sacramento, Los Angeles, Orange County, Chicago, Boston, New York, Philadelphia, and Washington, D.C. The company is a provider of networking solutions for businesses, using DSL technology to provide high-speed remote access to private networks and the Internet. Telecommunications services for Rhythms are provided by ACI, a wholly owned subsidiary of Rhythms. For more information, call 1-800-RHYTHMS, or visit the Web site at

Cisco Systems

Cisco Systems, Inc. (NASDAQ:CSCO) is the worldwide leader in networking for the Internet.

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This news release may contain forward-looking statements that involve risks and uncertainties. Actual results may differ materially because of various risks. These risks include risks associated with the demand and competition for the services and products to be sold by Rhythms, the continued availability of adequate financing to support our activities, the timing of rollouts in additional regions, the number of potential customers who could access such services, and our dependence on third parties for services such as providing collocation and transmission facilities, providing marketing and sales efforts, and supplying and installing equipment. For an expanded discussion on these and additional risks associated with Rhythms' business, please see the documents filed by Rhythms NetConnections Inc. with the U.S. Securities and Exchange Commission.

1. "Internet Services Hypergrowth," Forrester Research, February 1999.

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