Secure Short-Cut Routing for Mobile IP

This paper describes the architecture and implementation of a mobile IP system. It allows mobile hosts to roam between cells implemented with 2-Mbps radio base stations, while maintaining Internet connectivity. The system is being developed as part of a course on wireless networks at Harvard and has been operational since March 1994. The architecture scales well, both geographically and in the number of mobile hosts supported. It supports secure shortcut routing to mobile hosts using the existing Internet routing system without change. The implementation demonstrates a robust, low complexity realization of the architecture, and provides trade-off opportunities between efficiency and cost. Measured performance of the mobile system is generally excellent. The system can handle a high rate of location updates, and routes packets almost as efficiently for mobile hosts as the Internet does for stationary hosts. We observe reasonable TCP behavior during hand-offs.