What is the OSI model?

The OSI model, also known as the Open Systems Interconnection model, is a conceptual framework used to understand and standardize the functions of a telecommunications or computing system without regard to its underlying internal structure and technology. Its goal is to facilitate the interoperability of diverse communication systems with standard protocols. The OSI model divides the functions of a communication system into seven abstract layers, each serving a specific function and interacting with the layers directly above and below it.

1. Physical Layer: The bottom layer of the OSI model deals with the transmission and reception of the unstructured raw bit stream over a physical medium. It defines the electrical, mechanical, procedural, and functional specifications for activating, maintaining, and deactivating the physical link between end systems.

2. Data Link Layer: This layer provides node-to-node data transfer—a link between two directly connected nodes. It also handles error correction from the physical layer and controls the flow of data to ensure a smooth transmission. It is divided into two sublayers: the Media Access Control (MAC) layer and the Logical Link Control (LLC) layer.

3. Network Layer: The network layer is responsible for packet forwarding including routing through intermediate routers, as it handles the movement of packets among various networks. It is the layer where routing and forwarding as well as addressing (including IP addressing) take place.

4. Transport Layer: This layer provides transparent transfer of data between end systems, or hosts, and is responsible for end-to-end error recovery and