SC 21

Revision 2013

SC 21 “Information Retrieval, Transfer, and Management for Open Systems Interconnection”

SC21 was created in 1977 and disbanded in 1997. It played a major role in the foundation of networks through  definition of the OSI model and the upper layers protocols and services, as well as peripheral concepts including Security, Network Management,  Conformance Testing and Formal Description Languages. This work was done jointly with ITU-T; the OSI standards documents are available from the ITU-T as the X.200-series of recommendations.

At the creation of SC21, from ISO/TC97,  were Richard Desjardins and Hubert Zimmermann. The chairman of the US delegation was Richard DesJardins from NASA and he became the SC21 Chairman.

The OSI reference model was a major advance in the teaching of network concepts. It promoted the idea of a consistent model of protocol layers, defining interoperability between network devices and software. The OSI model was defined in raw form in Washington DC in February 1978 by Hubert Zimmerman of France and the refined standard was published by the ISO in 1984.


In this picture, on the left is Louis Pouzin from France. The fourth person from left is Hubert Zimmermann.

SC 21 Group