Modeling Hierarchical Caches in Content-Centric Networks

Content-Centric Network (CCN) provides a cleanslate design for the Internet, where content becomes the primitive of communications. In CCN, routers are equipped with content stores, which act as caches for frequently requested content. This design enables the Internet to provide content distribution services without any application-layer support. On the other hand, as caches are integrated into routers, the overall performance of CCN will be influenced by the caching efficiency. This paper studies the performance issues of caches in CCN, with the aim to gain some understanding on how caches should be designed to maintain a high performance in a cost-efficient way. Specifically, we use a two-dimensional discrete-time Markov chain to model the two-layer cache hierarchy formed by CCN routers, and develop an efficient algorithm to calculate the hit ratios of these caches. Simulations validate the accuracy of our modeling method, and convey some understanding on cache design in CCN.