Network Models

When dealing with networking, you may hear the terms "network model" and "network layer" used often. Network models define a set of network layers and how they interact. There are several different network models depending on what organization or company started them. The most important two are:

• The TCP/IP Model - This model is sometimes called the DOD model since it was designed for the department of defense It is also called the internet model because TCP/IP is the protocol used on the internet.
• OSI Network Model - The International Standards Organization (ISO) has defined a standard called the Open Systems Interconnection (OSI) reference model. This is a seven layer architecture listed in the next section. 

 http://www.comptechdoc.org/independent/networking/protocol/protmodels.html