Local Area Network (LAN)

A View of the Network

When you place mail in your mailbox, the mailman picks it up and takes it to the post office. If someone were to ask you where your mail was, you would probably respond with "well, the mailman picked it up and it's probably at the post office."

If we compare the mailbox to the PC or terminal in your office, we can compare the network to the postman and his route and further compare the post office to a host computer system on the network. Now let's imagine that you send electronic mail to a friend of yours who happens to be on a system at Georgetown University. Your mail message leaves your mailbox (or your PC) and is delivered to some local computer system (or post office) responsible for routing your mail. That message may be held and then routed onward via other host computers within the university and then subsequent lyrouted to a host computer outside the university. Finally, your mail message reaches the individual at Georgetown University.

This is actually a good example. It sets the stage for explaining the various networks involved in the whole picture. From our perspective, we will view the network as three pieces that are linked together: McClelland Hall, the University of Arizona, and the rest of the world.