Chapter 1: Introduction to Internetworking

CCDA Exam Topics Covered in This Chapter:

• Identify possible opportunities for network improvement.

As your mom probably told you, there’s really no better place to start than at the beginning. But what she likely didn’t warn you is that any process—internetworking being a classic example—takes its share of rabbit trails that dead-end. Other paths flourish into full-scale systems. One thing is certain: the changes in this industry have been mercurial. One day someone has a germ of a thought, and a few days later a new field emerges from that embryonic idea. Following these trails, however, can be a bit of a challenge.

So this is your primer—a course in the ABCs of internetworks. This opening chapter will examine the history of internetworking and then establish how it evolved into the technology of today. We’ll also describe the LAN and WAN equipment that’s typically found in a modern internetworking environment.

A necessary prerequisite to this is to fully understand the OSI reference model. I’ll show you how the layered approach to application development has created the present internetworking standards that shape how modern internetworking takes place. So relax; I’ll take you step-by-step through the fundamentals you need to learn.

The main topics addressed in this chapter are

• Identify and describe the functions of each of the seven layers of the OSI reference model.

• Describe the basic process of communication between the layers of the OSI reference model.

• Describe connection-oriented network service and connectionless network service and identify the key differences between them.

• Describe the basic process of information exchange between two applications across a network.

• Define flow control and describe the three basic methods used in networking.

• Identify the major standards organizations and bodies that specify internetworking standards.

• Define multiplexing and describe its function in internetworking.