We study a cache network in which intermediate nodes equipped with caches can serve requests. We model the problem of jointly optimizing caching and routing decisions with link capacity constraints over an arbitrary network topology. This problem can be formulated as a continuous diminishing-returns (DR) submodular maximization problem under multiple continuous DR-supermodular constraints, and is NP-hard. We propose a poly-time alternating primal-dual heuristic algorithm, in which primal steps produce solutions within $1-\frac{1}{e}$ approximation factor from the optimal. Through extensive experiments, we demonstrate that our proposed algorithm significantly outperforms competitors.

翻译：我们研究了一种中间节点配备缓存并可为请求提供服务的缓存网络。针对任意网络拓扑下链路容量约束的缓存与路由联合优化问题，我们将其建模为多连续递减回报超模约束下的连续递减回报子模最大化问题，该问题属于NP难问题。我们提出一种多项式时间的交替原始-对偶启发式算法，其中原始步骤能够产生达到最优解$1-\frac{1}{e}$近似因子的解。通过大量实验证明，该算法性能显著优于现有竞争方案。