OSI Model
Définition :
Developed by ISO[2] in 1983, the OSI[2] model comprises seven layers, numbered from bottom to top. Each layer has a specific task and communicates with the layers directly above and below it. Each layer has specific functions and protocols.[1]
Fondamental : How data moves through the OSI model?
When two devices communicate over a network, the data generated by an application must pass through several layers before reaching the physical medium. The OSI[2] model describes this process using a layered architecture where each layer performs a specific function.
As the data moves down the OSI[2] layers on the sender side, each layer adds its own control information called a header. This process is known as encapsulation. Each header contains information required by the corresponding layer on the receiving side.
When the data reaches the destination device, the reverse process occurs. As the data moves up through the OSI[2] layers, each layer removes the header that was added by the corresponding layer on the sender side. This process is called decapsulation.
Eventually, the original data is delivered to the application running on the receiving machine.
