The cost is truly trivial.
-R. Mechaley, April 22, 1992, Wall Street Journal,
"Cellular Carriers Announce Data Service"
This chapter presents an overview of Cellular Digital Packet Data technology-its history, objectives, services and architecture. CDPD is an open system definition which uses digital transmission on analog cellular (AMPS) channels to provide mobile packet-switched data services. CDPD is also a system concept, with a layered architecture which supports evolution to future technologies.
Many aspects of CDPD are generic in the sense that any wide area data network which supports mobility will share these aspects-both positive and negative. Other aspects of CDPD are unique to the cellular industry which is CDPD's heritage.
The purpose of CDPD is to provide mobile access to the services available via standard connectionless data protocols such as IP and CLNP. CDPD could be considered to be a wireless extension to the Internet which is available anywhere. As we shall see, CDPD could be easily enhanced to support other connectionless network protocols, such as IPv63.1 .