OSI Reference Model--The ISO Model of Architecture for Open Systems Interconnection

TLDR

ISO established a subcommittee in 1977 to create a standard architecture for heterogeneous computer networks, leading to the OSI Reference Model, which was also recognized by CCITT. The paper aims to present the SC16-developed architecture for Open Systems Interconnection as a framework for defining standard protocols. SC16 developed a seven‑layered architecture after 18 months of study and outlined initial protocol recommendations for the OSI Reference Model. The SC16 architecture, comprising seven layers, was adopted and its specifications passed in 1979, forming the basis for subsequent ISO standardization of Open Systems Interconnection protocols.

Abstract

Considering the urgency of the need for standards which would allow constitution of heterogeneous computer networks, ISO created a new subcommittee for "Open Systems Interconnection" (ISO/ TC97/SC 16) in 1977. The first priority of subcommittee 16 was to develop an architecture for open systems interconnection which could serve as a framework for the definition of standard protocols. As a result of 18 months of studies and discussions, SC16 adopted a layered architecture comprising seven layers (Physical, Data Link, Network, Transport, Session, Presentation, and Application). In July 1979 the specifications of this architecture, established by SC16, were passed under the name of "OSI Reference Model" to Technical Committee 97 "Data Processing" along with recommendations to start officially, on this basis, a set of protocols standardization projects to cover the most urgent needs. These recommendations were adopted by T.C97 at the end of 1979 as the basis for the following development of standards for Open Systems Interconnectlon within ISO. The OSI Reference Model was also recognized by CCITT Rapporteur's Group on "Layered Model for Public Data Network Services." This paper presents the model of architecture for Open Systems Interconnection developed by SC16. Some indications are also given on the initial set of protocols which will-likely be developed in this OSI Reference Model.