Replicated Object Management with Periodic Maintenance in Mobile Wireless Systems

In this paper we analyze periodic maintenance strategies for managing replicated objects in mobile wireless environments. Under periodical maintenance strategies, the system periodically checks local cells to determine if a replicated object should be allocated or deallocated in a cell to reduce the access cost. We develop a performance model based on Petri nets that considers the missing-read cost, write-propagation cost and the periodic maintenance cost with the objective to identify optimal periodic maintenance intervals to minimize the overall cost. The analysis results show that the overall cost is high when the user arrival-departure ratio and the read-write ratio work against each other and is low otherwise. In all cases, there exists an optimal periodic maintenance interval that would yield the minimum cost. Further, the optimal periodic maintenance interval increases as the arrival-departure ratio and the read-write ratio work in harmony.