User-defined consistency sensitive cache invalidation strategies for wireless data access

In order to fulfill users’ insatiable interests in accessing Internet services and information wirelessly, one of the key optimization techniques is caching frequently accessed data items in a local cache. A strong consistency is implicitly assumed in most caching schemes but it may cause a long query delay. In this paper, we propose a consistency-sensitive cache invalidation scheme, called ConSens, based on the existing Invalidation Report (IR) and Updated IR (UIR) based cache invalidation frameworks. In the ConSens scheme, each user is able to set its own consistency level with a server independently. This user-defined cache consistency can support diverse consistency requirements of applications. We also propose both lazy request and opportunistic data access techniques to effectively balance the data accessibility and query delay. In addition, we enhance the IR-based cache invalidation mechanism and propose a multiple data transmission scheme, called MDT, to further reduce the query delay. Extensive performance evaluation studies show that the proposed strategies can effectively balance the data accessibility, reduce the query delay, and significantly increase the number of opportunistic accesses according to the user-defined consistencies.