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 →)

Conductors that are separately supported with insulators on poles or towers above the surface of the Earth.
Note 1: Open wire conductors may be insulated or uninsulated.
Note 2: Open wire may be used in both communication applications and power applications.

1. In INFOSEC, an environment in which protection of data and resources from accidental or malicious acts is achieved through normal operational procedures. [After 2382-pt.8]
2. [An] environment that does not provide sufficient assurance that applications and equipment are protected against the loss of confidentiality, integrity, or availability. [INFOSEC-99]

An entity on which an operation is performed.

A set of rules defining the correct use of a Target of Evaluation [ITSEC].