Introduction to swftched multi-megabit data service (smds), an early broadband service

A broad spectrum of user needs and applications has kindled a rapidly growing market for high-speed data networking pro ducts and services Mufti-megabu-per-second links between powerful deshop consputers capitalize on existing hardware and s*ware investments. Motivated by the utility of high-speed networks, users and suppliersare searching for ways to wend themi beyond a single local area, eipecially as fiber-derived bandwidth eases technological constraints High speed leased line and privately-owned networks have emerged as possible solutions, offering high-speed connectivity between multiple 16 cations. However, public carriers can also provide switched high-speed data communications, offering customers the economic benefits of shared transmission facilities, combined with the equivalentprivacy and control characteristics of dedi cated networks. Switched Mufti-megabit Data Service (SMOS) has been proposed by Bellcore as a service to be offered in the early 1990s by its owner-clients, the Bell Operating Companies (BOCs) in the United States. Thispaper introduces SMDS, a packet-switched connection less (ie., dalagram) service designedfor high-speed data com munications over wide areas, for example, between subscriber sites within a Local Access and Transport Area (LATA). The motivations for oftring a service like SUDS are presented, and the features of SMDS are described. Possible applications are surveyeA including the interconnection of LocalArea Networks (LANs) and access to supercomputing facilities. To provide SUDS in the near term (early 1990s), emerging Metnapolitan Area Network (MAIV) standards and fechnoloSy will be exploited. Requirements on technology toprovideSUDS, as specified in Bellcore Technical Advisories TA-TSY-OW772111 and TA-7W-OW773121, describe how MCV standards and tech nology may be applied to the Subscriber-Network.Interface (SNI) and within network switching systems. The SUDS SNI uses familiarDS3 andDSI transmission lines, overlaid with an access protocol based on the IEEE P802.6 Distributed Queue Dual Bus (DQDB) MAN Pwposed Siandard'[3), allowing single or multi ple customer premises equipment (CPE) access MAN tech nology can also be used in the near term to provide high-speed switching capability within the network A high-level architec ture of the early network used to provide SUDS is diagrammed, and she prospects for supporting SMDS in the future with Broad band ISDIV (BISDM technology are highlighted.