What is OSI Model?

The OSI Model is a logical and conceptual model that defines network communication used by systems open to interconnection and communication with other systems. The Open System Interconnection (OSI Model) also defines a logical network and effectively describes computer packet transfer by using various layers of protocols.

Characteristics of OSI Model

Here are some important characteristics of the OSI model:

  • A layer should only be created where the definite levels of abstraction are needed.
  • The function of each layer should be selected as per the internationally standardized protocols.
  • The number of layers should be large so that separate functions should not be put in the same layer. At the same time, it should be small enough so that architecture doesn’t become very complicated.
  • In the OSI model, each layer relies on the next lower layer to perform primitive functions. Every level should able to provide services to the next higher layer
  • Changes made in one layer should not need changes in other lavers.

Here are essential landmarks from the history of OSI model:

  • In the late 1970s, the ISO conducted a program to develop general standards and methods of networking.
  • In 1973, an Experimental Packet Switched System in the UK identified the requirement for defining the higher-level protocols.
  • In the year 1983, OSI model was initially intended to be a detailed specification of actual interfaces.
  • In 1984, the OSI architecture was formally adopted by ISO as an international standard