Networking

CHAPTER 3

Application Layer Functionality and Protocols

The Study Guide portion of this chapter uses a combination of multiple-choice, matching, fill-in-the-blank, and open-ended questions to test your knowledge of the TCP/IP model application layer and the OSI model application, presentation, and session layers.

The Labs and Activities portion of this chapter includes all the online curriculum labs to further reinforce that you have mastered the practical, hands-on skills needed to work with the application layer of the OSI model.

As you work through this chapter, use Chapter 3 in the Network Fundamentals CCNA Exploration online curriculum, or use the corresponding Chapter 3 in the Network Fundamentals CCNA Exploration Companion Guide, for assistance.

Study Guide

Applications: The Interface Between the Networks

Visualizing the mechanisms that enable communication across the network is easier if you use the layered framework of the Open Systems Interconnection (OSI) model. In this section you explore the upper layers of both the OSI and TCP/IP models. How the human network generates data and how that data then enters the computer network is discussed. Application layer software and application layer services and protocols are examined in the labs.

When placed side by side, as shown in Figure 3-1, the OSI and TCP/IP models provide a means by which you can visualize and discuss the flow of networking.

Figure 3-1 OSI and TCP/IP Models

OSI Model TCP/IP Model

7 Application

6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

Application

Transport

Internet

Network Access

|Domain Name System |

|Hypertext Transfer |

|Protocol |

|Simple Mail Transfer |

|Protocol |

|Post Office Protocol |

|Dynamic Host |

|Configuration Protocol |

Vocabulary Exercise: Matching

In Table 3-1, match the term on the left...