Mathematical model for horizontal on-demand vEPC scalability in SDN-based environment

Next generation networks such as 5G provide a new approach for building highly scalable network infrastructure owing to NFV/VNF and SDN technologies. Infrastructure scalability allows a network operator to offer fine-graded on-demand services deployment. We consider virtualized Evolved Packet Core which functions are represented in form of several Virtual Network Functions. Computational capacity of every function could be extended via scaling mechanism with non-instantaneous activation/deactivation. In this paper we build a mathematical model of horizontal scaling for vEPC function in terms of queuing model with finite buffer size, several group of servers and queue thresholds. As a result, analytical formulas were derived and QoS metrics were proposed. Analytical evaluation shows that correct thresholds selection allows to significantly improve system performance.