An Active Updating Strategy for Caching Periodic Data in the Internet of Things

Named Data Network (NDN) can cache data in the router to reduce the data transmission cost and hence can be used in the resource limited Internet of Things systems. However, there are still some problems. Particularly for periodic data, if the cached data can't be updated in real time, the data content will be outdated. However, if each cache node updates the data frequently, it will cost a lot of unnecessary network traffic. In this paper, we improve the traditional NDN routing procedure and propose an active updating strategy for periodic data to further reduce the network traffic. First, we create an Interest Record Table and modify the Content Store to store the periodic information. Then, we modify the router work-flow to allow the router node to actively update the cache data. Finally, we propose an algorithm based on user's access regularity to calculate the update time point. Experimental results indicate that the proposed approach can reduce the network traffic by about 33.8\% on average compared to the existing competing methods.