The Internet is one of the 20th century's greatest communications developments. It allows people around the world to send e-mail to one another in a matter of seconds. We're all used to seeing the various parts of the Internet that come into our homes and offices -- the Web pages, e-mail messages and downloaded files that make the Internet a dynamic and valuable medium. But none of these parts would ever make it to your computer without a piece of the Internet that you've probably never seen. In fact, most people have never stood "face to machine" with the technology most responsible for allowing the Internet to exist at all: the router.

Routers are specialized computers that send your messages and those of every other Internet user speeding to their destinations along thousands of pathways. In this edition, we'll look at how these behind-the-scenes machines make the Internet work.

Introduction

Keeping the Messages Moving

Transmitting Packets

Knowing Where to Send Data

Understanding the Protocols

Backbone of the Internet