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The History and Purpose of the OSI Model

The OSI model was developed by the International Standards Organization (ISO) to help people understand complex activities by using abstract descriptions. Even though officially it was created in the 80’s the OSI had its origins in the 70’s by Mike Canepa, with Charlie Bachman of Honeywell Information Systems.

By the mid-70s, first there was a concern on database design and then on distributed database design. In order to support database equipment and distributed access, structured distributed communications architecture was required. By 1977, in the result of developing some concepts of management services, seven-layer architecture (distributed systems architecture) was built up.

When and Why the International Standards Organization Developed the OSI Model? It 1977 The British Standards Institute gave a proposition to the International Organization for Standardization for a standard architecture that was needed to identify the communications spread for distributed processing. The outcome of this proposal is a subcommittee that was formed on OSI.

Seven Layers of the OSI Model

The seven-layer model was chosen as the proposal to be presented to the ISO subcommittee. A description of the seven layers of the OSI model is offered bellow:

1. Application layer represents communication services and applications for everyone to use.
   1. Presentation layer negotiates the way data is delivered.
   2. Session layer determines and manages communications between cooperating parties.
   3. Transport layer manages data transmission and assures that the same data transmitted is received.
   4. Network layer addresses and delivers data between networks.
   5. Data Link layer is accountable for data transmission across the network.
   6. Physical layer determines network hardware characteristics.