The OSI (Open Systems Interconnection) Reference Model is a conceptual framework developed by ISO (International Organization for Standardization) to standardize network communication. In 1984, ISO officially introduced the OSI Reference Model.
The OSI model was created to make network communication simple, standard, and flexible. It provides a structured way to understand how data moves from one system to another and helps in developing and implementing networking protocols.
The OSI model was developed by ISO in 1984 to standardize network communication. It divides networking functions into seven layers, each performing specific tasks. The main purpose of the OSI model is to enable interoperability between different systems, simplify network design, and help in understanding and troubleshooting networks.
The Application layer is the topmost layer of the OSI model and acts as the interface between the user and the network. It provides network services directly to user applications. This layer does not provide services to other OSI layers but instead offers services such as file transfer, email, remote login, and web browsing. It allows users to access network resources and handles user authentication and service availability.
The Presentation layer is responsible for data representation and translation. It ensures that data sent by the sender is readable by the receiver. This layer handles data format conversion, encryption for security, and compression to reduce data size. It acts as a translator between different systems.
The Session layer establishes, manages, and terminates communication sessions between applications. It controls dialog management and synchronization between systems. This layer ensures that data exchange happens smoothly by setting checkpoints and maintaining sessions during data transfer.
The Transport layer is responsible for reliable data transfer between systems. It breaks data into smaller segments, performs error detection and recovery, and ensures data is delivered in the correct sequence. This layer controls flow and congestion and uses protocols like TCP and UDP.
The Network layer handles routing and logical addressing of data packets. It determines the best path for data to travel from the source to the destination across multiple networks. This layer uses IP addresses and is responsible for packet forwarding, routing, and congestion control.
The Data Link layer ensures error-free transmission of data between two directly connected nodes. It packages raw data into frames and uses physical (MAC) addresses for device identification. This layer also handles error detection, flow control, and access control to the physical medium.
The Physical layer is responsible for the transmission of raw bits over the communication medium. It defines hardware specifications such as cables, connectors, voltage levels, and transmission speed. This layer deals with the physical connection between devices.