Optimizing Video Request Routing in Mobile Networks with Built-in Content Caching

Built-in content caching in mobile core networks can help improve quality of service, reduce operation expenses, simplify inter-network cooperation, and thus is a promising approach for more efficient networking architectures. In addition to the complexity of content placement as revealed in the literature, routing video requests remains a challenging issue. Two problems must be addressed: (i) how to distribute video requests among multiple internal servers (i.e., server selection); and (ii) how to route so-generated video flows (i.e., flow routing). In this work, we jointly formulate these two problems with two traffic-engineering objectives considered, namely, minimizing maximum link utilization and minimizing total link cost. We develop fast algorithms to solve the problems with provable approximation guarantees. We then propose a hop-by-hop routing protocol, which implements the optimization solutions by generating a set of flow-splitting and routing decisions for each router/caching node. Simulation results show that our algorithms significantly outperform existing routing schemes under various system settings, reducing up to 68 percent of maximum link utilization and more than 50 percent of link cost, and supporting over 60 percent more of traffic load.