What is the OSI model?

The OSI (Open Systems Interconnection) model is a reference model for computer networks and communication systems. This model provides a framework for how communication in computer networks should be structured. The OSI model consists of seven layers, and each layer serves a different function in communication:
1. Physical Layer: Responsible for converting data into electrical signals, optical signals, or radio waves for transmission.
2. Data Link Layer: Ensures reliable transmission of data over the physical medium and handles error correction.
3. Network Layer: Determines how data packets should be routed between source and destination and performs routing functions.
4. Transport Layer: Ensures reliable, sequenced, and accurate delivery of data flow to the destination.
5. Session Layer: Manages communication rules and handles session initiation, maintenance, and termination.
6. Presentation Layer: Converts data formats, encrypts, and compresses data to ensure compatibility between different systems.
7. Application Layer: Enables users to access the network and exchange data between various applications.

Each layer communicates with the layer above it to perform data transfer and provides services to the layer below it. In this way, the OSI model organizes and standardizes network communication.