Network Warrior, 2nd Edition

Chapter 1. What Is a Network?

Before we get started, I would like to define some terms and set some ground rules. For the purposes of this book (and your professional life, I hope), a computer network can be defined as “two or more computers connected by some means through which they are capable of sharing information.” Don’t bother looking for that in an RFC because I just made it up, but it suits our needs just fine.

There are many types of networks: local area networks (LANs), wide area networks (WANs), metropolitan area networks (MANs), campus area networks (CANs), Ethernet networks, Token Ring networks, Fiber Distributed Data Interface (FDDI) networks, Asynchronous Transfer Mode (ATM) networks, Frame Relay networks, T1 networks, DS3 networks, bridged networks, routed networks, and point-to-point networks, to name a few. If you’re old enough to remember the program Laplink, which allowed you to copy files from one computer to another over a special parallel port cable, you can consider that connection a network as well. It wasn’t very scalable (only two computers) or very fast, but it was a means of sending data from one computer to another via a connection.

Connection is an important concept. It’s what distinguishes a sneaker net, in which information is physically transferred from one computer to another via removable media, from a real network. When you slap a USB drive (does anyone still use floppy disks?) into a computer, there is no indication that the files came from another ...