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OSI Referential Model

This model was created by the ISO organization as the main part of its effort to standardize computer networks and was approved as international standard ISO 7498 in 1984. The complete wording of the standard was accepted also by the CCITT as recommendation X.200. The task of the referential model is to provide a basis enabling the creation of standards for the purpose of interconnecting different systems. Any open system made according to this model is an abstract model of a real open system. The standard therefore does not specify the implementation (realization) of systems, but merely states general principles of the seven-layer network architecture. It describes the layers, their functions and services. It does not include any protocols that would require too many details.

Application layer
Presentation layer
Session layer
Transport Layer
Network Layer
Data link layer
Physical layer