In my TechNotes I wrote: The OSI (Open System Interconnection) model is developed by ISO in 1984 to provide a reference model for the complex aspects related to network communication. It divides the different functions and services provided by network technology in 7 layers. This facilitates modular engineering, simplifies teaching and learning network technologies, helps to isolate problems, and allows vendors to focus on just the layer(s) in which their hardware or software is implemented and enables them to create products that are compatible, standardized, and interoperable.[/i]