A combination of standards-based interfaces specifying a complete interface between an application program and the underlying application platform [POSIX.0].

The comprehensive set of interfaces, services, and supporting formats, plus user aspects for interoperability or portability of applications, data, or people, as specified by information technology standards and profiles [POSIX.0].

1. 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 hierarchical structure, (b) allows each layer to provide a set of accessible functions that can be controlled and used by the… (Read More →)

Pertaining to the logical structure for communications networks standardized by the International Organization for Standardization (ISO).
Note: Adherence to the standard enables any OSI-compliant system to communicate with any other OSI-compliant system for a meaningful exchange of information.

Communications system architecture that adheres to the set of ISO standards relating to open systems architecture.

The lowest level of abstraction within the OSI standards scheme.
Note: Each OSI--Protocol Specification operates at a single layer. Each defines the primitive operations and permissible responses required to exchange information between peer processes in communicating systems to carry out all or a subset of the services defined within the OSI--Service Definitions for that layer.

The next lower level of abstraction below that of the OSI--Reference Model. The OSI--Service Definitions for each layer define the layer's abstract interface and the facilities provided to the user of the service independent of the mechanism used to accomplish the service.

In the Application Layer of the OSI--Reference Model (OSI--RM), the set of functions related to the management and status of various resources identified in all layers of the OSI--RM.

1. An abstract description of the digital communications between application processes running in distinct systems. The model employs a hierarchical structure of seven layers. Each layer performs value-added service at the request of the adjacent higher layer and, in turn, requests more basic services from the adjacent lower layer:Physical Layer: Layer
1. The lowest of seven hierarchical layers. The Physical… (Read More →)

An all-dielectric waveguide in which electromagnetic waves are guided by a refractive index gradient so that the waves are confined to the guide by refraction or reflection from the outer surface of the guide or from surfaces within the guide.
Note 1: In an open waveguide, the electromagnetic waves propagate, without radiation, within the waveguide, although evanescent waves coupled to… (Read More →)