OSI - open systems interconnection

reference model developed by ISO to enable different or similar systems to dialogue with one another
NOTE 1: This model constitutes a reference framework for describing data exchanges. Each layer performs a service at the request of the adjacent higher layer, and in turn, requests more basic services from the lower layers. It is described in 7 layers.
NOTE 2: Open systems interconnection (OSI) is an international effort to facilitate communications among computers of different manufacture and technology.

Application Area: Traffic Control Systems