Today’s Internet is arguably the largest engineered system ever created by mankind, with hundreds of millions of connected computers, communication links, and switches; with billions of users who connect via laptops, tablets, and smartphones; and with an array of new Internet-connected devices such as sensors, Web cams, game consoles, picture frames, and even washing machines. Given that the Internet is so large and has so many diverse components and uses, is there any hope of understanding how it works? Are there guiding principles and structure that can pro- vide a foundation for understanding such an amazingly large and complex system? And if so, is it possible that it actually could be both interesting and fun to learn about computer networks? Fortunately, the answers to all of these questions is a resounding YES! Indeed, it’s our aim in this book to provide you with a modern introduction to the dynamic field of computer networking, giving you the principles and practical insights you’ll need to understand not only today’s networks, but tomorrow’s as well.
This first chapter presents a broad overview of computer networking and the Internet. Our goal here is to paint a broad picture and set the context for the rest of this book, to see the forest through the trees. We’ll cover a lot of ground in this intro- ductory chapter and discuss a lot of the pieces of a computer network, without los- ing sight of the big picture.