News Release

CapRock Communications Launches New BROADband Networking Initiative with IP+ATM Solutions from Cisco Systems

CapRock to Build Public Fiber Optic IP+ATM Network for
May 20, 1999

CapRock to Build Public Fiber Optic IP+ATM Network for Delivery of Advanced, Value-Added Services

DALLAS, Texas -- May 20, 1999 -- CapRock Communications Corp. (NASDAQ: CPRK), a Southwestern facilities-based integrated communications provider (ICP), announced today that it is investing $20 million to deploy an advanced fiber optic network based on IP+ATM switching solutions from Cisco Systems, Inc. Designed to support the bandwidth requirements of the 21st century, CapRock's 5500-mile regional fiber network will enable carrier, business, and residential customers throughout the Southwestern U.S. to communicate via integrated data, voice, video, and Internet services at higher speeds and at lower costs than ever before. CapRock will also be able to co-ordinate joint marketing, technology sharing, and selling activities with Cisco for its network services.

"After in-depth analysis, we chose Cisco IP+ATM solutions as the basis for our new BROADband, enhanced-data network," says Ignatius Leonards, president of CapRock Communications. "Cisco's IP+ATM capabilities enable us to provide customers with the best of both worlds - revenue-generating enhanced high-speed data services and innovative IP-based services, with the quality of service that customers demand."

A High-Speed, Multiservice Foundation

The network's design incorporates six bidirectional line switching OC-48 SONET rings and dense wave division multiplexing (DWDM). The IP+ATM infrastructure is based on Cisco MGX 8800 series wide-area switches, which form a robust, fault-tolerant IP+ATM backbone. Voted "Best of Show" at Comnet '99, the Cisco MGX 8800 brings the richness of Cisco IOS. software to carrier-class multiservice networks, enabling business IP services with strong service level agreements and reduced operating costs. Featuring the industry's widest breadth of service interfaces, the Cisco MGX 8800 with Multiprotocol Label Switching (MPLS) will enable CapRock to deploy IP, ATM, Frame Relay, and private line replacement services and value-added data and voice services while scaling from DS0 to OC-48/STM-16 speeds.

CapRock will also deploy Cisco BPX. 8650 wide-area switches, which incorporate MPLS to provide end-to-end QoS support for IP and ATM traffic. The Cisco BPX 8650 is the industry's first ATM WAN switch in production with a carrier-class implementation of MPLS. Both platforms provide high scalability, enabling CapRock to keep up with subscriber demand for a wide range of IP+ATM services. Both the platforms also allow CapRock to take advantage of emerging opportunities, such as demand for switched voice, without continuous infrastructure turnover.

Broadband Connections to Customers

CapRock also plans to deploy an advanced IP optical network using the Cisco 7500 series and Cisco 7200 series router platforms. MPLS will be used to switch routed traffic over the wide-area IP+ATM backbone. Using the Cisco AS5800 and Cisco AS5300 universal access platforms, CapRock plans to deploy voice over IP (VoIP) and virtual private dial network (VPDN) services.

"The focus of this effort is to deliver high-demand, New World services based on Cisco IP+ATM solutions," said Kevin Kennedy, senior vice president of the Service Provider Line of Business at Cisco Systems. "CapRock Communications takes its commitment beyond the fiber network backbone and plans to deploy a robust broadband connection to its customers as well."

"We are committed to becoming a dominant integrated communications provider, which means we require the best technology for our next- generation applications," said Leonards. "Our position as the leading alternative communications carrier in the Southwest enables us to accelerate our efforts in delivering bundled services of our products."

As part of its continuing commitment to provide leading-edge services, CapRock has also become one of a select group of Cisco Powered Network program participants. Cisco Powered Network certification communicates to CapRock's customers that CapRock services are reliable and secure and deliver the performance required for today's integrated communications applications.

About CapRock Communications

CapRock is a regional facilities-based integrated communications provider offering local, long-distance, ATM, Frame Relay, private-line, high-speed Internet, and enhanced data services tailored to business and retail customers. The company also provides switched and dedicated access, domestic and international long distance, bandwidth, and dark fiber to carrier customers.

Cisco Systems

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

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Statements contained in this news release regarding expected financial results and other planned events are forward-looking statements, subject to uncertainties and risks. Among many factors that could cause actual results to differ materially from those expected are the following: (a) the substantial indebtedness of the Company including the interest charges associated therewith and the financial covenants imposed upon the Company by such indebtedness; (b) the Company's ability to manage rapid change and its ability to continue the integration of its predecessor companies; (c) supply and demand for data services; (d) the Company's ability to fund the significant capital requirements in order to complete its planned growth including its fiber network; (e) the Company's ability to successfully, timely and cost-effectively complete its fiber network; (f) the development of provisioning, billing, customer service and management information systems; (g) competition in the various segments of the communications industry in which the Company seeks to participate; (h) dependence upon other long distance carriers and local exchange carriers, both as customers and as suppliers; (i) dependence upon key personnel; (j) dependence upon major customers and the risk associated with international customers; (k) the regulation of the Company's industry; (l) possible service interruptions or natural disasters; (m) potential liability of internet service providers; (n) need to obtain and maintain rights of way; (o) compliance with Year 2000 issues; and (p) protection of the Company's intellectual property.

MGX is a trademark and Cisco, Cisco IOS, Cisco Systems and the Cisco Systems logo are registered trademarks of Cisco Systems, Inc. in the U.S. and other countries. All other brand names and trademarks mentioned in this document are properties of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any of its resellers.