With the rapid growth in the number of mobile devices like cellular phones, personal digital assistants (PDAs), and laptop computers, the demand for “anywhere, anytime, and any way” high-speed Internet access is becoming a primary concern in our lives. Mobile IP has been designed with the Internet Engineering Task Force (IETF) to serve the needs of growing population of mobile computer users who wish to connect to the internet and maintain communication as they move from place to place. Mobile IP enables a wireless network node to move freely from one point of connection to the Internet to another, without disrupting the end-to-end connectivity. The goals of this paper are to define the fundamentals of mobile IPV4, elaborate the problems of mobile IPV4, give a brief overview of some of the literature that deals with the fundamentals of mobile IPV6, explain the problems of mobile IPV6, compare Mobile IPv6 and Mobile IPv4, discuss the advantages of mobile IP, and review the application of mobile IP for vehicular networks.