A collection of ISO model diagrams are available in this post for free! A variety of 101 Diagramss provided will help you in studying the structure of the ISO model diagram. The Open System Interconnections (ISO) model defines a networking framework to implement protocols in layers, with control passed from one layer to the next. It is primarily used today as a teaching tool. It conceptually divides computer network architecture into 7 layers in a logical progression. See the first example of the 7 layers diagram in the following image.