Energy-Efficient Service Function Chain Provisioning

Network function virtualization (NFV) is a promising network architecture concept to reduce operational costs. In legacy networks, network functions, such as firewall or TCP optimization, are performed by specific hardware. In networks enabling NFV coupled with the software defined network (SDN) paradigm, virtual network functions (VNFs) can be implemented dynamically on generic hardware. This is of primary interest to implement energy-efficient solutions, in order to adapt the resource usage dynamically to the demand. In this paper, we study how to use NFV coupled with an SDN to improve the energy efficiency of networks. We consider a setting in which a flow has to go through a service function chain, which is several network functions in a specific order. We propose an integer linear programming (ILP) formulation, an ILP-based heuristic, and a decomposition model that relies on joint routing and placement configuration to solve the problem. We show that virtualization provides between 22% and 62% of energy savings for networks of different sizes.