Computer networks.

Abstract

We have looked at several aspects of networks in this article. As you read about networks, and use them, we hope our discussions will help you understand some of the associated concepts and terms. For instance, suppose someone describes an Ethernet installation as a bus topology LAN using the 1-persistent CSMA/CD protocol with horizontal cables on each floor connected by repeaters to a vertical cable backbone running from the basement to the roof. You now have seen what that description implies. To close this article, we ask you to refer back to Figure 1. Our sample network transfer from Marie to Lars was described as being accomplished through a number of layers or steps, most of which were transparent to the users. Building upon the material presented in this article, we can now give you a more detailed illustration of those layers. Figure 13 shows the seven layers in network model defined by the International Standards Organization, ISO: application, presentation, session, transport, network, data link, and physical. We do not have space here to discuss each layer in detail, but Figure 13 does give a typical operation that is done in each layer.