O:- Open

S:- systems

I:- interconnection

The OSI (Open Systems Interconnection) model is a conceptual framework used to describe the functions of a networking system. It divides the networking process into seven distinct layers that communicate with each other to provide a complete networked system. The seven layers of the OSI model are:

Physical Layer – This layer deals with the physical connection and transmission of signals between devices.
Data Link Layer – This layer establishes and controls access to the physical medium, detects errors, and provides flow control.
Network Layer – This layer determines how data is routed between devices on different networks.
Transport Layer – This layer ensures reliable communication between devices by providing end-to-end error recovery and flow control.
Session Layer – This layer establishes, maintains, and terminates communication sessions between devices.
Presentation Layer – This layer addresses issues related to data representation, such as data compression and encryption.
Application Layer – This layer provides services that directly support user applications, such as email and file transfer.

Think of the OSI model like a seven-story building. Each floor represents a different aspect of how computer systems communicate, from the physical wires and signals at the bottom to the user interface at the top. It helps in understanding and organizing the complexities of network communication .