7 – Application: Interface to end user. Interaction directly with the software applications.
6 – Presentation: Formats Data to be “presented” between application-layer entities.
5 – Session: Manages connections between local and remote applications.
4 – Transport: Ensures integrity of the data transmission.
3 – Network: Determines how data gets from one host to another.
2 – Data Link: Defines the format of data on the network.
1 – Physical: Transmits raw bit stream over a physical medium.