The Cellular Digital Packet Data (CDPD) Network is a peer multi-protocol, connectionless network, proposed by the CDPD Forum, a trade association of carriers, equipment suppliers, and application developers. It is based on early IETF Mobile-IP work so the two proposals have many similarities but also some differences. The idea behind CDPD is that it may share unused channels in existing Advanced Mobile Phone Systems (AMPS) to provide a 19.2 kbps data channel. The CDPD describes in detail the three lower network layers.
The terminologies of CDPD and Mobile-IP are different. CDPD is following the OSI model terminology. The mobile node is called a mobile end-system (M-ES), the home and foreign agents are called mobile home and mobile serving functions (MHF and MSF respectively) and reside in a mobile data intermediate system (MD-IS). A mobile data base station (MDBS) is also defined which deals with the airlink communications and acts as a data link layer relay between the M-ES and the serving MD-IS. Two protocols, the Mobile Node Registration Protocol (MNRP) and the Mobile Node Location Protocol (MNLP) are responsible for registration of the M-ES with its home MD-IS and the proper routing of packets destined for the M-ES.
How do Mobile IP and CDPD compare? We can compare these mobile data systems from a variety of perspectives including:
The final topic in our comparison is a prediction and a discussion of issues surrounding co-existence and convergence between these standards.
Obviously, the goal is to objectively compare Mobile IP and CDPD. In particular,