The Open System interconnection model is a conceptual model for defining and standardizing network communication mechanisms. there are 7 abstract layers. each layer has its distinct functionality. provides an interface for its predecessor and successor.
Functional details are hidden within the current layer so that the next layer is not required to have knowledge about its predecessor and successor ( other than the standardized interfaces)
Every layer can add its own header to a data package to transfer management information. these headers are only used by the corresponding layer on the other machine