Towards optimal cache decision for campus networks with content-centric network routers

Abstract

A traditional approach to solving the large delay problem of campus networks is to upgrade the link connecting the gateway to the Internet. Inspired by the emerging content-centric network (CCN) and software defined network (SDN) architecture, we propose an alternative solution where the campus network uses a few CCN routers with caching ability, so that duplicate requests for the same content can be satisfied locally without traffic from the Internet. In our solution, we formulate the problem of deciding the cached content at each router to minimize the total delay of all requests. We prove that the problem is NP-hard, and no polynomial time algorithm can provide a constant approximation ratio, unless P=NP. We then propose an exponential-time exact algorithm and three polynomial-time heuristic algorithms. Numerical results show that our solution can reduce network delay significantly, compared to existing cache decision algorithms.