The OSI stands for open system interconnection. The OSI model is a standard developed by the international standard organization in 1984. It is actually a reference model that gives an ideal infrastructure of network communication. As we know that the network communication is a lengthy and complicated process and very hard to understand. Thus, the OSI reference model divides the complete and lengthy communication process into seven independent layers. Each layer is assigned a particular task that it performs. Different protocols are used at these different layers to perform that assigned task.
The OSI model defines completely how the data flows down the seven layers at the sending end, and how it moves up through these layers at destination end of communication process. These layers communicate with the corresponding layers at the other end that is the physical layer of sending end communicated with the physical layer at the destination device. Thus the data is moved and processed by these layers in opposite direction at the destination relative to the sending devise. First three layers application layer, session layer and presentation layer are known as application layers and the rest of the layers are called data layers. All the protocols follow this model either completely or partially.
The OSI model defines completely how the data flows down the seven layers at the sending end, and how it moves up through these layers at destination end of communication process. These layers communicate with the corresponding layers at the other end that is the physical layer of sending end communicated with the physical layer at the destination device. Thus the data is moved and processed by these layers in opposite direction at the destination relative to the sending devise. First three layers application layer, session layer and presentation layer are known as application layers and the rest of the layers are called data layers. All the protocols follow this model either completely or partially.
