Open systems architecture

In telecommunications, open systems architecture (OSA) is a standard that describes the layered hierarchical structure, configuration, or model of a communications or distributed data processing system. It enables system description, design, development, installation, operation, improvement, and maintenance to be performed at the abstraction layers in the hierarchical structure. Each layer provides a set of accessible functions that can be controlled and used by the functions in the layer above it. Each layer can be implemented without affecting the implementation of other layers. The alteration of system performance by the modification of one or more layers may be accomplished without altering the existing equipment, procedures, and protocols at the remaining layers.^[3]

Examples of independent alterations include the conversion from wire to optical fiber at a physical layer without affecting the data link layer or the network layer, except to provide more traffic capacity, and the altering of the operational protocols at the network level without altering the physical layer.^[3]

• Hardware Open Systems Technologies
• Architecture of Interoperable Information Systems
• Architectural pattern
• Enterprise architecture
• OSI model
• Open-system environment reference model

• General Services Administration (1991). "Federal Standard 1037C". Institute for Communication Science.
• Guertin, Nickolas; Hurt, Thomas (1 October 2013). DTIC ADA608725: DoD Open Systems Architecture Contract Guidebook for Program Managers: A Tool for Effective Competition (Report). Defense Technical Information Center.
• Sage, Andrew P. (1992). Systems Engineering. New York: Wiley-interscience. ISBN 0471536393. OCLC 473169047.

 This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 22 January 2022.