|  |  | Overview

During the past two decades there has been a tremendous increase in the numbers and sizes of networks. Many of the networks, however, were built using different implementations of hardware and software. As a result, many of the networks were incompatible and it became difficult for networks using different specifications to communicate with each other. To address this problem, the International Organization for Standardization (ISO) researched many network schemes. The ISO recognized that there was a need to create a network model that would help network builders implement networks that could communicate and work together (interoperability) and therefore, released the OSI reference model in 1984.

This chapter explains how standards ensure greater compatibility and interoperability between various types of network technologies. In this chapter, you will learn how the OSI reference model networking scheme supports networking standards. In addition, you will see how information or data makes its way from application programs (such as spreadsheets) through a network medium (such as wires) to other application programs located on other computers on a network. As you work through this chapter, you will learn about the basic functions that occur at each layer of the OSI model, which will serve as a foundation as you begin to design, build and troubleshoot networks.