International Standards Organization/Open System Interconnect model

Application layer The seventh, or highest, layer in the International Organization for Standardization s Open Systems Interconnection (ISO/OSI) model for computer-to-computer communications. This layer uses services provided by the lower layers, but is completely insulated from the details of the network hardware. It describes how application programs interact with the network operating system, including database management, e-mail, and terminal emulation programs. 

OSI (Open Systems Interconnection) model A protocol model, developed by the International Standards Organization (ISO), that was intended to provide a common way of describing network protocols. This model describes a seven-layered relationship between the stages of communication. Not every protocol maps perfectly to the OSI model, as there is some overlap within some the layers of some protocols. 

This network became known as ARPANET. In the I980 s the International Organization for Standardization (ISO) implemented its Open Systems Interconnection—Reference Model (OSI—RM) to facilitate the interoperability of different hardware components. The creation in the I990 s of new software and programming languages, such as browsers and HTML, made the explosive growth of Internet activity and Web sites possible. 

Open systems interconnection (OSI) model A framework for organizing networking technology developed by the International Standards Organization. 

One of the first standards for computer communications was proposed and developed by the International Standards Organization (ISO) in the early 1980s. This network architecture model, the open systems interconnection (OSI) reference model shown in Fig. 1, describes a network through seven layers. On any of these layers, one or more protocols can implement the functions specified for the layer. Some protocol specifications based on this... 

Most often found is the data communication system based on TCP/IP (Transmission Control Protocol/ Internet Protocol) as well as IEEE 802 (Institute of Electrical and Electronics Engineers) protocols. By relying on the model of ISO OSI (International Organization for Standardization Open Systems Interconnection) the model of such a system can be presented in a manner shown in Figure 2. 

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