An efficient cache invalidation scheme to support strong data consistency in a mobile ad-hoc network

Caching consistency in a MANET environment is an important issue as it is directly related to MANET connectivity. However, existing cooperative caching schemes mostly focus on delta and/or weak consistency. Recently, RPCC was proposed, but it cannot overcome traditional PUSH and PULL methods in terms of ensuring a strong consistency. In this paper, we propose three algorithms that are based on the PUSH method. They not only satisfy strong consistency but also reduce the amount of query delay by adaptively adjusting the IR interval. The first algorithm gradually sends an IR more frequently when some data items receive an increasing number of requests. The second algorithm adjusts the IR interval by predicting which data items will become more popular. The last algorithm is a hybrid of the first two which covers diverse environments. Simulation results demonstrate that our algorithms reduce the delay time by 61% and improve success ratio by 6%. However, they also increase the traffic cost by 20% compared to the PUSH method.