Chapter 6 – Wireless Networks

Publisher Summary This chapter covers the basics of wireless network design and architectures. The primary difference between wired and wireless networks is that wireless networks use a special type of electric current known as radio frequency (RF), which is created by applying alternating current to an antenna to produce an electromagnetic (EM) field. Devices for broadcasting and reception use the resulting RF field. In the case of wireless networks, the medium for communications is the EM field, the region of space that is influenced by electromagnetic radiation. The EM field is dispersed according to the properties of the transmitting antenna, and not tightly bound as is the case with communication over a wire. Wireless local area networks (LANs) have suddenly become an attractive element to many companies and home users because of the increased mobility provided by the technology as well as its ease and low cost of deployment. Enterprise wireless networks utilize the IEEE 802.11 specification for wireless LANs. Initially the security of 802.11 networks was seriously flawed with the use of the WEP protocol but has evolved to the much stronger and robust Wi-Fi Protected Access (WPA) and WPA-2 standards specified in 802.11i.