What is OSI layer?

The OSI (Open Systems Interconnection) model is a conceptual framework that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology. It divides the communication system into seven abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. Each layer performs a specific set of functions, and communicates with the layers above and below it. It is commonly used as a reference model for understanding and designing network protocols and architectures.