Having finished all the preliminaries, we now come to the layer where all the applications are found. The layers below the application layer are there to provide transport services, but they do not do real work for users. In this chapter, we will study some real network applications.

However, even in the application layer there is a need for support protocols, to allow the applications to function. Accordingly, we will look at an important one of these before starting with the applications themselves. The item in question is DNS, which handles naming within the Internet. After that, we will examine three real applications: electronic mail, the World Wide Web, and multimedia. We will finish the chapter by saying more about ...

Get Computer Networks, Fifth Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.