AS 4021-1992

Refines the basic reference model for OSI to provide a framework for co-ordinating the development of existing and future application layer Standards. In particular it defines the nature of Standards in the application layer and the relationships among them, the architectural framework in which individual OSI application layer protocols shall be developed and the categories of identifiable objects which are necessary for the specification and operation of protocols; and relates distributed information processing activities to the Standards in the application layer. This Standard is identical with and has been reproduced from ISO/IEC 9545:1989.