In the first two chapters, we established the foundation for exploring the physical aspects of a network. We learned about cables and the various methods of connecting them so that we can share data. Now that we can physically link computers, we need to learn how to gain access to the wires and cables.
In this chapter, we explore the three principal methods used to access the wires. The first method, called contention, is based on the principle of "first come, first served." The second method, token passing, is based on the principle of waiting to take turns. The third method, demand priority, is relatively new and is based on prioritizing access to the network. Later in the chapter, we continue our discussion of network architecture by examining the data itself and how it is put together before it is sent on its way. Last, we examine the most common network systems (Ethernet, Token Ring, AppleTalk, and ArcNet).
This chapter continues to build on the lessons presented in chapters 1 and 2. You are expected to be familiar with the concepts of topology, network cabling, and network interface cards discussed in those chapters.