Open systems architecture, in telecommunication, is a standard that describes the layered hierarchical structure, configuration, or model of a communications or distributed data processing system that:
- Enables system description, design, development, installation, operation, improvement, and maintenance to be performed at a given layer or layers in the hierarchical structure
- Allows each layer to provide a set of accessible functions that can be controlled and used by the functions in the layer above it
- Enables each layer to be implemented without affecting the implementation of other layers
- Allows the alteration of system performance by the modification of one or more layers without altering the existing equipment, procedures, and protocols at the remaining layers
Examples of independent alterations
- Converting from wire to optical fibers at a physical layer without affecting the data link layer or the network layer except to provide more traffic capacity
- Altering the operational protocols at the network level without altering the physical layer
Open systems architecture may be implemented using the OSI Model as a guide while designing the system to meet performance requirements.