OSI Seven Layer Model

OSI Seven Layer Model 

The open system interconnection model (osi model) is a conceptional model that characterized and standardized the communication function of telecommunication or computing system without regard of their underlying internal structure and technology. its goal is the interoperability of diverse communitcation systems with standard protocols. The model partitons a communication system into abstraction layers. The original version of the model defined seven 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 application above it , while it calls the next lower layer to send and receive packets that comprise the content of that path. Two instances at the same layer are visualized as connected by a horizental connection in that layer.

OSI Seven Layer Model Layers Includes:

1. Physical Layer
2. Data Link Layer 
3. Network Layer
4. Transport Layer
5. Session Layer 
6. Presentation Layer 
7. Application Layer 

These layers are divided into two categories:

1. Media Layer 
2. Hosted Layer