The OSI model, or Open Systems Interconnection model, is a conceptual framework that divides network communications functions into seven layers. It was developed in the late 1970s to support the emergence of diverse computer networking methods that were competing for application in large national networking efforts around the world. The OSI model provides a common basis for the coordination of standards development for the purpose of systems interconnection.
The seven layers of the OSI model are:
- Physical layer: This layer is responsible for transmitting raw bits over a communication channel.
- Data link layer: This layer is responsible for transmitting data frames over a communication channel between two adjacent nodes.
- Network layer: This layer is responsible for routing data packets between nodes on different networks.
- Transport layer: This layer is responsible for providing reliable end-to-end data delivery services.
- Session layer: This layer is responsible for establishing, managing, and terminating sessions between applications.
- Presentation layer: This layer is responsible for data representation, encryption, and compression.
- Application layer: This layer is responsible for providing network services to applications.
The OSI model is a universal language for computer networking and characterizes computing functions into a universal set of rules and requirements to support interoperability between different products and software. It is still used today as a means to describe network architecture.
