The convergence of three technology paradigms, viz. light-weight portable computers, the spread of wireless networks and services, and the ubiquitous Internet, aimed at allowing users the freedom to connect to the Internet at any time and in any place, to read email, query databases, retrieve information from the web or to entertain themselves, makes mobile computing a very promising prospect as well as a very formidable challenge. This paper details the mechanism of operation of Mobile IP network protocol, designed and developed to enable efficient and effective communication between a mobile host and a remote server. The paper then also looks at the efficiency versus effectiveness trade-off, the issues of network security against malicious masqueraders and other areas of current research interest.