This chapter introduces data communication networks and their basic components. It discusses protocols and standards used in networks as well as organizations that develop networking standards. Figures 1-1 through 1-3 provide illustrations of data communication system components, the layers of the OSI reference model, and examples of network standards.

2. Figure 1-1 WCB/McGraw-Hill  The McGraw-Hill Companies, Inc., 1998 Data Communication System Components

3. Figure 1-2 WCB/McGraw-Hill  The McGraw-Hill Companies, Inc., 1998

4. Figure 1-3 WCB/McGraw-Hill  The McGraw-Hill Companies, Inc., 1998