COMMUNICATIONS GUIDE
Fast Packet Data Services
Frame Relay, SMDS Ideal for Transmissions Across Wide-Area Networks
new generation of fast-packet data services has emerged in the federal communications market. Frame relay and Switched Multimegabit Data Service (SMDS) are slowly gaining acceptance by agencies with geographically dispersed offices. These services are particularly useful for organizations with high-performance applications residing on separate local-area networks (LANs). They provide a flexible, economic way to reconfigure data networks as traffic changes and technology evolves.
Frame Relay. Six-year-old frame-relay technology works by switching and forwarding groups of computer bits-called data frames-across wide area networks (WANs). It is ideally suited for medium-speed LAN interconnection applications, such as database queries and small-to-medium file transfers.
The technology, which is provided by companies such as AT&T, Bell Atlantic, Sprint and MCI, is much more cost-effective than dedicated private lines since connections are not priced by distance. And since multiple connections can be established over single lines, frame relay can reduce the number of router ports required.
Frame-relay networks are being used by a variety of federal agencies, including Agriculture, DoD, NASA and Treasury. Congress uses frame-relay services to link House and Senate offices on Capitol Hill with legislators' home bases. The Postal Service uses a frame-relay network to link nearly 500 post offices around the country.
SMDS. Switched Multimegabit Data Service is a high-speed, broadband data-transmission service that is used to connect LANs to WANs. It uses a universal addressing system that eliminates the need to establish dedicated point-to-point connections. Flat-rate charges make SMDS ideal for transfers of high-bandwidth graphics files.
NASA uses SMDS to transmit everything from satellite-construction drawings and climate-research images to administrative files such as e-mail and spreadsheets. The service is even used to connect the agency to off-site contractors. But SMDS is only available in certain parts of the country. BellSouth, GTE and U S WEST offer local service while Bell Atlantic and MCI provide long-distance links.
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