Computer networking is one of the most exciting and important technological fields
of our time. The Internet interconnects millions (and soon billions) of computers,
providing a global communication, storage, and computation infrastructure. More-
over, the Internet is currently being integrated with mobile and wireless technology,
ushering in an impressive array of new applications. Yes, computer networking has
indeed come a long way since its infancy in the 1960s. But this is only the begin-
ning—a new generation of creative engineers and computer scientists will drive the
Internet to yet unforeseen terrains. This book will provide today’s students with the
vehicles they need to journey to and explore the new lands in this exciting field.
This first chapter presents an overview of computer networking and the Inter-
net. Our goal here is to paint a broad-brush picture of computer networking, to see
the forest through the trees. We’ll cover a lot of ground in this introductory chapter
and discuss a lot of “pieces” of a computer network, while not losing sight of the
“big picture.” The chapter lays the groundwork for the rest of the book. It can also
be used for a mini-course on computer networking.
In this chapter, after introducing some basic terminology and concepts, we will
first examine the “edge” of a computer network. We’ll look at the end systems and
network applications, and the transport services provided to these applications.
We’ll then explore the “core” of a computer network, examining the links and the
switches that transport data, as well as the access networks and physical media that
connect end systems to the network core. We’ll learn that the Internet is a network
of networks, and we’ll learn about how these networks connect with each other.
After having completed this overview of the “edge” and “core” of a computer
network, we’ll take a broader view. We’ll examine the causes of data-transfer delay
and loss in a computer network, and provide simple q