OSI Model
The OSI (Open Systems Interconnection) model was created by the ISO to help standardize communication between computer systems. It divides communications into seven different layers, which each include multiple hardware standards, protocols, or other types of services. This model is composed of seven layers : (1) the physical layer (media, signal and binary transmission) ; (2) the data link layer (physical adressing) ; (3) the network layer (path détermination and logical addressing) ; (4) the transport layer (end-to-end connections, reliability and flow control) ; (5) the session layer (interhost communication, managing sessions between applications) ; (6) the presentation layer (data representation, encryption and decryption, convert machine dependent data to machine independent data) ; (7) the application layer (network process to application).