Document Type

Technical Report


Computer Science and Engineering

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Technical Report Number



With the advent of wireless technology and laptops, mobility is an important area of research. A fundamental problem in this area is the delivery of messages to a moving mobile. Current solutions work correctly only for slowly moving nodes that stay in one location long enough for tracking to stabilize. In this paper we consider the problem of message delivery to rapidly moving mobile units. With these algorithms, we introduce a new method for designing algorithms based on the paradigm of considering a mobile unit as a message, and adapting traditional message passing algorithms to mobility. Our first algorithm is based on tracking and can be efficient when the path of the mobile node exhibits considerable locality. While it uses the Dijkstra-Scholten algorithm for diffusing computations as a point of departure, the final algorithm adds a number of mechanisms. Our second example is a search algorithm based on transforming the classic Chandy-Lamport snapshot algorithm. The algorithm generalizes to multicasting to a set of rapidly moving mobiles. Both our algorithms are based on the assumption that messages and mobiles travel through the same FIFO channels. We show how to enforce this assumption by modifying existing handover protocols.


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