Energy-Efficient Video-On-Demand Content Caching and Distribution in Metro Area Networks

The success of novel multimedia services, such as video-on-demand (VoD) is leading to a tremendous growth of Internet traffic. Content caching can help mitigate such uncontrolled growth by storing video content closer to the users in core, metro, and access network nodes. So far, fixed, and, especially, mobile access networks have evolved independently, leveraging logically (and often also physically) separate infrastructures. This means that mobile users cannot access caches placed in the fixed access network (and vice-versa) even if they are geographically close to them, and energy consumption implications of such undesired effect must be investigated. In this paper we perform an evaluation of energy-efficient VoD content caching and distribution under static and dynamic traffic in converged networks as well as in non-converged networks. We define an integer linear programming optimization problem modeling an energy-efficient placement of caches in core, metro, and fixed/mobile access nodes where energy is minimized by powering-on and -off caches located in different segments of the network and by performing an energy-efficient VoD-request routing. To deal with problem complexity, we propose an energy-efficient content caching and VoD-request routing heuristic algorithm, which is also adopted under dynamic traffic scenarios. Our results show how deploying caches in the access and metro network segments can reduce the overall energy consumption of the network. Moreover, results show how the evolution toward a fixed-mobile converged metro/access network, where fixed and mobile users can share caches, can reduce the energy consumed for VoD content delivery.