OSI Reference Model

The Open Systems Internet working Model is a hierarchical model made my ISO for the inter networking between different types of Systems. It is a hierarchical model consisting of layers.

Layers
It consists of seven layers, named as:

Physical Layer


 * 1) Data Link Layer


 * 1) Network Layer


 * 1) Transport Layer


 * 1) Session Layer


 * 1) Presentation Layer


 * 1) Application Layer

The lower three layers are responsible for application communication between hosts. The lower three layers are responsible for transporting data.

Usage
it is one of the most widely used Models in the world.