Chapter . How Computers Communicate

The OSI Model

At some point, everyone involved with networking comes across a reference to the Open System Interconnection (OSI) seven-layer model. What is the seven-layer model, and why is it relevant?

The OSI seven-layer model describes the functions for computers to communicate with each other. The International Organization for Standardization (ISO) published this model in 1984 to describe a layered approach for providing network services using a reference set of protocols called OSI. The basis of the definition is that each of the seven layers has a particular function it must perform, and each layer needs to know how to communicate with only the layers immediately above and below it.

At the time of the definition ...

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