The OSI (Open Systems Interconnection) model is a conceptual framework that defines the architecture of computer networks. Developed by the International Organization for Standardization (ISO), it provides a standardized way to understand and communicate about network functionality. The OSI model consists of seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. Each layer builds upon the previous one, enabling data to be transmitted efficiently and reliably across networks. By breaking down network communication into these distinct layers, the OSI model facilitates the design, implementation, and troubleshooting of computer networks, ensuring interoperability and seamless communication between devices from different vendors.
History
The history of the OSI model dates back to the late 1970s, when there was a need for a common standard for systems interconnection. At that time, various computer networking methods were emerging, and there was a lack of interoperability between them.
The development of the OSI model began in the late 1970s to support the emergence of diverse computer networking methods that were competing for application in large national networking efforts worldwide. The British Department of Trade and Industry acted as the secretariat, and universities in the United Kingdom developed prototypes of the standards.
The OSI model was first defined in raw form in Washington, D.C., in February 1978 by French software engineer Hubert Zimmermann. The refined but still draft standard was published by the International Organization for Standardization (ISO) in 1980.
The OSI model was created to provide a common basis for the coordination of standards development for the purpose of systems interconnection. The idea behind OSI was to get everyone in the industry to agree on standards for interoperability across vendors. At the time, many devices and networks were leveraging and supporting many different protocols, and many devices were cropping up, speaking different languages.
The OSI model was intended to serve as the foundation for the establishment of a widely-adopted suite of protocols that would be used by international internetworks, basically what the Internet became. However, the OSI model never gained traction amongst vendors, and the TCP/IP model began to make headway in the 1980s and 1990s.
Despite this, the OSI model is still used today as a reference for describing network protocols, training IT professionals, and interfacing with multiple architectures. It provides a handy common-ground representation that unifies different communication systems into an abstract hierarchy, making it easy to understand, teach, and learn how to do networking effectively.
In summary, the OSI model was created to provide a common standard for systems interconnection, to promote interoperability across vendors, and to establish a widely-adopted suite of protocols for international internetworks. Although it did not achieve its original objective, it has become a widely-used tool for education, development, and network management.
