Internetworking software allows computers attached to physically distinct data networks to communicate with one another. The recent advent of portable computers suggest that soon a substantial fraction of all computers can and will move. Because present computers rarely move, new approaches to internetworking are required. This research investigates how to extend present internetworking protocols to support mobile computers. The approach is a combination of forwarding, multicasting, address reassignment, and link-level techniques. The results will be a suite of protocols for locale discovery, dynamic address assignment, establishment and destruction of forwarding chains, and notification to higher-level protocols of a change of locale. The work will be evaluated via simulation and demonstration implementation of their ideas within IP internetworking software.