- The process, overall structure, framework, logical components, and logical interrelationships that are based on open-industry-standards and pervasive industry de facto standards, rather than on closed, proprietary design. Conceptually, an architecture that is open will facilitate interoperability, portability, and scalability as well as provide competitive choices and solutions.
- The layered hierarchical structure, configuration, or model of a communications or distributed data processing system that
(a) enables system description, design, development, installation, operation, improvement, and maintenance to be performed at a given layer or layers in the
(b) allows each layer to provide a set of accessible functions that can be controlled and used by the functions in the layer above it,
(c) enables each layer to be implemented without affecting the implementation of other layers, and
(d) 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.
Note: Examples of independent alterations include
(a) 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, and
(b) altering the operational protocols at the network level without altering the physical layer.