A Hybrid Termination Detection Protocol for Wireless Mobile Distributed Systems

The emergence of mobile/nomadic computing environment , which has been made possible by the maturity of wireless networking technologies and the popularity of small, light, economic hand-held laptops, palmtops, and PDAs, has provided a new way of conducting computation. Incorporating mobile components into a distributed system has posed new challenges to the design of distributed computation. This paper studies a fundamental problem in distributed computing, the termination detection problem, in such a mobile environment. We survey two types of termination detection protocols, the diiusion-based schemes 4, 6] and the weight-throwing schemes 7, 10], that are designed for traditional static distributed systems. We then propose a hybrid scheme by bridging these two protocols together. The hybrid scheme is a semi-centralized one, with a central coordinator at the wired backbone and each of the wireless cells. The scheme can better exploit the communication hierarchy (in terms of wired and wireless bandwidths) and can pave the gaps of computation and communication capability between static and mobile hosts, thus more scalable to larger distributed systems. Through analyses and simulations, we demonstrate that our hybrid scheme requires less space and computation power of mobile hosts and consumes less wireless communication bandwidth than existing schemes.