Chapter 1. Introduction to Wireless LAN Technologies

Networks have become a pervasive element of everyday life. Even though they can adopt different physical characteristics and carry diverse payloads, they all share a common set of fundamental attributes. The essence of a network is the fact that it connects or relates objects or devices.

The instantiation of this connection can adopt many forms. It can be intangible, as is the case in an organizational or relational network, or it can be tangible. Examples of tangible networks include a highway system, an electrical grid, and data communications networks. These types of networks are designed and built to interconnect nodes so that objects can be moved between source and destination. The highway system permits people and goods to be moved between any two points by means of a meshed infrastructure of roads. The electrical grid transports electrons between the power generating plants and the points of consumption. Finally, data communications networks carry informationthat is voice, video, or datafrom respective sources to destinations. The definitions of source and destination are purposely left open because they include people in addition to mechanical and electronic machines.

The Business Case for Enterprise-Class Wireless LANs focuses on a specific subset of data networks, namely wireless local area networks (WLANs). As such, from here on you shall see the term network refer exclusively to data communications networks.

This chapter introduces you to the value of mobility in data communications. Various scenarios are presented to briefly illustrate the socioeconomic benefits of mobility solutions. This chapter focuses on helping you develop an understanding of WLAN technology. We illustrate the OSI framework and how WLANs relate to other internetworking technologies that include LAN, WAN, and mobile cellular solutions. The framework will also help position the WLAN-specific concepts that are covered throughout the remainder of this chapter.