OSI (Open Systems Interconnection) Model - secuguru/security-terms GitHub Wiki

The OSI Model (Open Systems Interconnection Model) is a conceptual framework that divides network communication into seven layers. Each layer is responsible for specific functions, and it explains the process of data communication step by step. The layers of the OSI Model are as follows:

  1. Physical Layer

This layer deals with the physical medium necessary for data transmission. It includes cables, electrical signals, and network devices such as hubs and repeaters.

  1. Data Link Layer

This layer bundles the data transmitted from the physical layer into frames and is responsible for error detection and correction, as well as flow control. Ethernet and switches are part of this layer.

  1. Network Layer

This layer handles routing data to its destination using IP addresses. Routers and the IP protocol are included in this layer.

  1. Transport Layer

This layer ensures the reliability of data transmission, establishes sessions, and controls data flow. TCP and UDP protocols are representative of this layer.

  1. Session Layer

This layer manages communication sessions, opening and closing sessions before and after data transmission. It includes synchronization and session management. 6 Presentation Layer This layer performs functions like data format conversion, encryption, and compression, preparing the data for use by the application layer.

  1. Application Layer

This is the layer that users directly interact with, allowing application software to use network services. HTTP, FTP, and SMTP are examples of protocols in this layer.

This model is useful for understanding how each layer interacts in real-world networks and helps in diagnosing and solving network issues.