Open Systems Interconnection (OSI) is a reference model for understanding and developing compatible networking and communication practices. The OSI model illustrates the relationships between all components of a network and provides a framework that allows each layer to serve distinct purposes and work independently of each other according to their separate functions. Froehlich (2021) argues that the OSI model is “theoretical in nature and should only be used as a general guide,” but it serves an important purpose in creating a clear framework for understanding how a telecommunication system should work. The different terminologies and formats between the different OSI model layers help make distinctions between the specific roles and tasks that take place throughout a network and aid in the planning, design, and troubleshooting of the network. In 1984, the International Organization for Standardization (ISO) proposed Open Systems Interconnection (OSI) as a common framework for networking technology.
The OSI uses conceptual abstraction to separate the layers into compartmentalized slices based on function that can be evaluated as a piece at a time (Froehlich, 2021). The seven layers of the OSI model work in cascading hierarchy, each layer serving the layer above it and being served by the layer below it. The highest layer is the application layer which is followed by the presentation layer, session layer, transport layer, network layer, data-link layer, and finally the physical layer. The OSI model creates a framework that benefits from its adaptability, security, and flexibility; and has become a standard model in networking.
The disadvantages of the OSI model include the fact that layers cannot work in parallel with each other and they must wait for the next layer to send data to them, the session layer and the presentation layer aren’t as useful as the other layers, and it is a theoretical model that has physical restrictions on its practical implementation (Froehlich, 2021).
References
Froehlich, A. (2021). OSI model (Open Systems Interconnection). TechTarget. https://www.techtarget.com/searchnetworking/definition/OSI