The OSI model consists of 7 layers that describe what happens when a terminal talks to a computer or when one computer talks to another.
The OSI model is like a layered cake. At the top, running the software which the user actually sees, is the application layer. At the bottom, holding everything up, is the physical layer which is made up of wiring, cables or radio signals.
These are the layers-
Prof. Ashay Dharwadker