On Design of Caching Threshold of Caching Strategy CDO for ICN

In recent years, Information-Centric Networking (ICN) which mainly focuses on the transferred data rather than the sending and receiving hosts has attracted attention. To realize ICN as a future Internet architecture, it is required that ICN is robust against network failures such as a disaster and errors of network equipments. In our previous work, we proposed a caching strategy called CDO (Caching based on Distance to Originals), which achieves the high content availability at network failure in ICN. In the CDO, a router caches a content only when the hop distance between the origin of the content and itself is greater than or equal to a given caching threshold. However, in our previous work, we focused on only maximizing the AMDC (Average Maximum hop Distance to Caching copies) which leads to the content availability at the network failure, and did not sufficiently consider the cache hit ratio, i.e., the probability that the requested content is returned from one of routers. Therefore, in this paper, we study how to design the caching threshold of the CDO, which aimed at achieving the high AMDC and the high cache hit ratio using the CDO. Especially, we consider the optimal design method of caching threshold using a weighted sum and the design method of caching threshold for each content. As a result of investigating the effectiveness of the two types of the design methods through experiments, we show that the cache hit ratio can be significantly improved while maintaining the high AMDC by appropriately designing the caching threshold of the CDO.