On the effectiveness of a counter-based cache invalidation scheme and its resiliency to failures in mobile environments

Caching frequently accessed data items on the client side is an effective technique to improve the performance of data dissemination in mobile environments. Classical cache invalidation strategies are not suitable for mobile environments due to the disconnection and mobility of the mobile clients. One attractive cache invalidation technique is based on invalidation reports (IRs). However, IR-based approach suffers from long query latency and it cannot efficiently utilize the broadcast bandwidth. In this paper, we propose techniques to address these problems. We first extend the UIR-based approach to reduce the query latency. Then, we propose techniques to efficiently utilize the broadcast bandwidth based on counters associated with each data item. Novel techniques are designed to maintain the accuracy of the counter in case of server failures, client failures, and disconnections. Extensive simulations are provided and used to evaluate the proposed methodology. Compared to previous IR-based algorithms, the proposed solution can significantly reduce the query latency, improve the bandwidth utilization, and effectively deal with disconnections and failures.