What is the OSI model?The OSI model is a model that characterizes the communication functions of a telecommunication system with a strong regard for their underlying internal structure and technologyThe OSI model is a conceptual model that characterizes the communication functions of a telecommunication system without regard to their underlying internal structure and technologySet of specifications that network hardware manufacturers must respect

The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes the functions of a communication system into seven categories, known as layers. This model was developed by the International Organization for Standardization (ISO) to facilitate interoperability between different products and software.

The seven layers of the OSI model are:

1. Physical Layer: This layer is responsible for the physical connection between devices. It defines the electrical and physical specifications for devices.

2. Data Link Layer: This layer is responsible for node-to-node data transfer and error detection and correction.

3. Network Layer: This layer is responsible for transferring variable length data sequences from one node to another node in the same network.

4. Transport Layer: This layer is responsible for the transfer of data between end systems, or hosts, and is responsible for error recovery and flow control.

5. Session Layer: This layer is responsible for setting up, coordinating, and terminating conversations, exchanges, and dialogs between applications.

6. Presentation Layer: This layer provides independence from differences in data representation by translating from application to network format, and vice versa.

7. Application Layer: This layer supports application and end-user processes, such as email, file transfer, and web browsing.

Each layer serves the layer above it and is served by the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of that path.