Analytical Models for QoS-driven VNF Placement and Provisioning in Wireless Carrier Cloud

Network Function Virtualisation (NFV) represents a promising solution for wireless network operators to improve business agility and cope with the continuing growth in data traffic. Furthermore, by virtualizing core network functions as well as radio-access network functions, NFV can effectively reduce the cost to deploy and operate large wireless networks. Face to this technology revolution, a new underlying cloud architecture is emerging. This architecture is based on the combination of edge clouds and a centralized cloud, referred to as the edge-central cloud. This notably improves user experience while ensuring scalability and load balancing. In such carrier cloud environment, efficient management mechanisms for the Virtual Network Functions (VNFs) are of crucial importance. In this paper, we introduce VNF placement and provisioning optimization strategies over an edge-central carrier cloud infrastructure taking into account QoS requirements (i.e., response time, latency constraints and real-time requirements) and using analytical and QoS models. Our main design goals are to optimize resource utilization, to prevent cloudlet overload, and to avoid violation of SLA requirements. We propose different solutions to achieve a trade-off between these conflicting objectives according to the wireless operator requirements. These solutions are evaluated through extensive simulations using different performance metrics and encouraging results are obtained.