OSI model: Difference between revisions

Revision as of 10:07, 7 July 2014

Revision as of 11:08, 7 July 2014

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{{OSIstack}}

The '''OldOpen Systems Interconnection model''' ('''OSIESOSI''') is a [[conceptual model]] that characterizes and standardizes the internal functions of a [[communication system]] by partitioning it into [[abstraction layer]]s. The model is a product of the [[Open Systems Interconnection]] project at the [[International Organization for Standardization]] (ISO), maintained by the identification ISO/IEC 7498-1.

The model groups communication functions into seven logical layers. A layer serves the layer above it and is served by the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of that path. Two instances at one layer are connected by a horizontal connection on that layer.

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==History==

Work on a layered model of network architecture was started and the [[International Organization for Standardization]] (ISO) began to develop its OSI framework architecture. OSI had two major components: an ''abstract model'' of networking, called the Basic Reference Model or seven-layer model, and a set of specific protocols. 'ῌΙ'

The concept of a seven-layer model was provided by the work of [[Charles Bachman]], Honeywell Information Services. Various aspects of OSI design evolved from experiences with the [[ARPANET]], the fledgling Internet, NPLNET, EIN, [[CYCLADES]] network and the work in IFIP WG6.1. The new design was documented in ISO 7498 and its various addenda. In this model, a networking system was divided into layers. Within each layer, one or more entities implement its functionality. Each entity interacted directly only with the layer immediately beneath it, and provided facilities for use by the layer above it.