than you might think. In the case of MAN versus WAN versus CAN, beware of absolutes. In other areas of networking, the terms are more specific. For our purposes, we will define these network types as follows: A LAN is a network that is confined to a limited space, such as a building or floor. It uses short-range technologies such as Ethernet, Token Ring, and the like. A LAN is usually under the control of the company or entity that requires its use. Chapter 1: What Is a Network? A WAN is a network that is used to connect LANs by way of a third-party provider. An example is a Frame Relay cloud (provided by a telecom provider) connecting corporate offices in New York, Boston, Los Angeles, and San Antonio. A CAN is a network that connects LANs and/or buildings in a discrete area owned or controlled by a single entity. Because that single entity controls the environment, there may be underground conduits between the buildings that allow them to be connected by fiber. Examples include college campuses and industrial parks. A MAN is a network that connects LANs and/or buildings in an area that is often larger than a campus. For example, a MAN might connect a company's various offices within a metropolitan area via the services of a telecom provider. Again, be careful of absolutes. Many companies in Manhattan have buildings or data centers across the river in New Jersey. These New Jersey sites are considered to be in the New York metropolitan area, SO they are part of the MAN, even though they are in a different state. Terminology and language are like any protocol: be careful how you use the terms you throw around in your daily life, but don't be pedantic to the point of annoying other people by telling them when and how they're wrong. Instead, listen to those around you and help educate them. A willingness to share knowledge is what separates the average IT person from the good one. What Is a Network? CHAPTER 2 Hubs and Switches In the beginning of Ethernet, 10Base-5 used a very thick cable that was hard to work with 