ISO-IEC 7498-1 OSI Basic Reference Model Overview.pdf

ISO-IEC 7498-1 OSI Basic Reference Model, jointly published by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), serves as a comprehensive standard known as the OSI Basic Reference Model. This model functions as a communication protocol reference model, elucidating the communication processes between computer or communication systems and delineating how data transmission and control occur within these systems. The OSI Basic Reference Model divides the communication process into seven layers, each layer imbued with distinct functions and protocols. Sequentially from the bottom up, these layers are: Physical Layer, responsible for converting data into physical signals and facilitating transmission in the network; Data Link Layer, ensuring reliable data frame transmission on physical connections, inclusive of error detection and correction; Network Layer, managing addressing and routing in the network, as well as transmitting data packets from source to destination nodes; Transport Layer, ensuring reliable data transmission, error detection and correction, and controlling flow and congestion; Session Layer, responsible for establishing, managing, and terminating sessions in the network; Presentation Layer, overseeing data format conversion, data encryption and decryption, as well as data compression and decompression; Application Layer, providing a spectrum of services including file transfer, email, and web browsing.