OSI Reference Model (OSI)

The International Organization for Standardization (ISO) developed the Open System Interconnection OSI Reference Model to describe how information is transferred from one machine to another machine from the point when a user enters information using a keyboard and mouse to when that information is converted to electrical or light signals transferred along a piece of wire or radio waves transferred through the air. It is important to understand that the OSI Reference Model describes concepts and terms in a general manner and that many network protocols such as IP and IPX fail to fit nicely into scheme explained in OSI model. Therefore the OSI Reference Model is most often used as a teaching and troubleshooting tool. By understanding the basics of the OSI Reference Model you can apply these to real protocols to gain a better understanding of them as well as to more easily troubleshoot problems.