Description: This is an explanatory document intending to help define what the OSI model is in terms of computer networking.

OSI, stands for Open Systems Interconnection, is a series of ‘layers’ used in network communication. These layers define certain parts of network, all of which combine to make up the internet, your home network, or any other network.

The OSI model represents what happens on different levels of the network between two networked applications. In the OSI model there are seven layers of networking - starting with the Physical layer and ending with the Application layer. The seven layers are what make up the OSI model. A complete list of network layers is as follows:

1. Physical
2. Data Link
3. Network
4. Transport
5. Session
6. Presentation
7. Application