What is the OSI model?

The OSI model (open systems interconnection) was established by ISO in order to implement a communications standard between computers that are on a network (the rules that manage the communications between computers on a network). The aim of having the system, in layers is to separate the problem into different parts depending on their level of abstraction. Each of the layers of the OSI model will communicate with an adjacent level that would be above or below it. The OSI model has 7 layers while the TCP/IP model only has 4. These layers are the PHYSICAL LAYER – that defines the way in which data is physically converted into digital signals on the communication media such as electric pulses, light modulation etc., THE DATA LINK LAYER – that defines the interface with the network interface card and the sharing of the transmission media, THE NETWORK LAYER – that makes it possible to manage addressing and routing of any data (their path via the network), THE TRANSPORT LAYER – this is in charge of data transport, its division into packets and management of potential transmission errors, THE SESSION LAYER – which defines the opening and destruction of communication sessions between networked machines, THE PRESENTATION LAYER – that defines the format of data that is handled by the application layer independently of the system, and finally THE APPLICATION LAYER – that provides the interface with applications and is the closest level to the users, managed directly by the software.