A method and apparatus for maintaining communications between a mobile computer and a mobile subscriber unit is disclosed. The method and apparatus comprise determining whether a connection is available between the mobile subscriber unit and a radio communications system. If a connection is available, then the method and apparatus include retrieving a first IP address for the mobile computer from the radio communications system. Then, the method and apparatus comprise caching the first IP address in the mobile subscriber unit for use by the mobile computer. Finally, the method and apparatus include utilizing the first IP address even if the radio communications system is unavailable and updating the first IP address with a second IP address obtained from the radio communications system when the radio communications system is available.