Open System Interconnection Reference Model - OSI Model

The OSI Reference Model is founded on a suggestion developed by the International Organization for Standardization (ISO). The model is known as ISO OSI (Open Systems Interconnection) Reference Model because it relates with connecting open systems – that is, systems that are open for communication with other systems. It was developed in 1984. It defines a networking framework for implementing protocols in seven layers.
Layers in the OSI model are ordered from lowest level to highest.The stack contains seven layers in two groups:The layers are stacked this way:
* Application
* Presentation
* Session
* Transport
* Network
* Data Link
* Physical
The upper layers of OSI model are application, presentation and session layer. The software in these layers performs application-specific functions like data formatting, encryption, and connection management.
The lower layers are transport, network, data link and physical layer. These layers provide more primitive network-specific functions like routing, addressing,and flow control.

Benefits of OSI model

- Helps users understand how hardware and software elements function together.
- OSI is independent of country.
- OSI is independent of the operating system.
- Makes troubleshooting easier by separating networks into manageable pieces.
- Helps users understand new technologies as they are developed.