A novel optimization scheme for caching in locality-aware P2P networks

Deploying cache has been generally adopted by Internet service providers (ISPs) to mitigate P2P traffic in recent years. Most traditional caching algorithms are designed for locality-unaware P2P networks, which mainly consider the requested frequency of contents as the principle of caching policies. However, in more prevalent locality-aware conditions with biased neighbor-selection policies, the existing caching schemes can hardly optimize the situation. In this paper we show that, what need to be cached in locality-aware conditions are the contents that can not be well provided by local neighbors, rather than the contents which are requested most frequently. Therefore, states of local neighbors should be taken into consideration in caching policies. We first present a new model in which P2P cache and locality-aware neighbor selection work together. We focus on inter-ISP traffic and available bandwidth of users in order to benefit both ISPs and users. Based on the mathematical model, a novel caching algorithm is proposed which considers replacement and allocation policies together. According to trace-driven simulations, the proposed algorithm outperforms other two representative caching algorithms in various scenarios.