The ISO Reference Model of Open Systems Interconnection

Abstract

During the 1970's computing facilities which had previously provided stand-alone processing were linked into a variety of networks under quite different geographical, technical, financial and application constraints. The effect of these independent developments was that similar services were often provided by quite different mechanisms, and interconnection became extremely difficult. Late in the 1970's a strong desire for a standard means of internetwork communication arose. It was realized that a common model of distributed data communications would be required to facilitate the development of these standards. Intensive activity was initiated by several national and international standards organizations, including the International Organization for Standardization (ISO). In 1978 the “Reference Model of Open Systems Interconnection” [8] was produced, and this led to the 1981 Draft International Standard 7498 “Data Processing. Open Systems Interconnection - Basic Reference Model” [2]. The documents assume an environment of systems which make themselves “open” to the exchange of data with other systems by adhering to a well-defined set of standard procedures for communication. The documents scope includes not only the basic transfer of information between such systems, but also the capability of such systems to work together in support of distributed applications.