Open Systems Interconnect
(OSI)

Open System Interconnect (OSI) Model

The Open Systems Interconnect (OSI) model was developed by the Institute for Organizational Standards (ISO) to organize the technologies used in data communications into a layered model to help reduce the complexities and improve the processes involved. The OSI model is one of two models used for the standardization and development of data communication technologies, the other model known as the D.O.D. or Internet model is shown next to the OSI model in the table below.

Networking Layers, PDUs, and Protocols By Model

Instructions: Click on a layer name in the OSI column below to view more information about the layer. Pay close attention to the numerical order of the layers, the data format of the PDUs at each layer, and which protocols operate at which layer. Also, you'll need to know the names and stacking order of the two sub-layers of the Data Link layer.