In this chapter, you will be introduced to one of the two main network models in use today: the OSI model. The other TCP/IP model will be covered in the next chapter. These two models form a collection of standards that vendors and developers follow that ensure the compatibility of network devices and software. While both models are important, the OSI model always seems to be the one people talk about. It is beneficial for you, as a network engineer, to understand how this model works and how each layer interacts with the others to help facilitate troubleshooting.
This chapter begins by explaining the rationale behind the concept of network models, which is then followed by an explanation of the functionality of each of the seven layers of the OSI model. As we discuss each layer, protocols and devices will be mapped to each.
The following topics will...