To understand Wireless Networking, there are two things that are fundamental: Transmission Control Protocol/Internet Protocol (TCP/IP) and radio waves. TCP/IP governs how data flows across the Internet, whether it is over a dial-up modem, a cable modem, or a wireless network. Radio waves surround us; some carry useful information, others are just noise. This book is more concerned with the former, but the noise is of interest too, since it can drown out the useful signals. The first half of this chapter explains TCP/IP, and the second discusses radio waves. The rest of this book looks at how the two work together.