Dynamic Service Chaining for Ultra-Reliable Services in Softwarized Networks

Network softwarization is a paradigm shift for the next generation of network. Network Function Virtualization (NFV) softwarizes network functions as virtual network function (VNF) instances on top of a network infrastructure. Along with the merits of flexibility, programmability and reduced function provisioning cost, softwarization of network functions introduces new challenges of service's reliability due to possible hardware failures, software bugs and hacker attacks. Currently reliable service provisioning schemes based on first-order statistics fails in accounting for the ultra-reliable needs of mission-critical services. In this paper, we propose a dynamic service chaining (DSC) framework to provision ultra-reliable services where the reliability is characterized by the probability distribution using extreme value theory. Our design objective is to minimize the number of backup VNF modules subject to reliability and resource constraints. Due to the dynamic nature of network, primary and backup VNFs are re-mapped to higher reliable physical machines in order to provide ultra-reliable services. Using Lyapunov stochastic optimization, primary VNF mapping and backup VNF selection are performed in the large and small timescales respectively. Numerical results show that the proposed DSC framework can guarantee ultra-reliable network services efficiently.