Deployment of VNF Service Chains with Grooming and Resilience in Elastic Optical Networks

Network function virtualization (NFV) uses virtual network functions (VNFs) and VNF service chains (VNF-SCs) as a flexible and cost-efficient way of providing network services. This new backbone plays a vital role in dealing with the outbreak of traffic patterns generated by diverse services. Elastic optical networks (EONs) can be used for maximum flexibility to interconnect the computing infrastructure and data centers (DCs) required to host these VNFs and effectively transport the heterogeneous traffic flowing through the VNF-SC. The aim of the paper is to provide a complete mixed integer linear programming (MILP) formulation for the problem of VNF-SC deployment with survivability to minimize the total number of functions, balance the load utilization through grooming, and avoid spectrum fragmentation in EONs. In addition, we propose an efficient heuristic solution in dealing with the problem of large networks. The performance of the proposed strategies is evaluated based on the availability of resources (function computing capability). Simulation results show that the proposed MILP and heuristic can reduce the total amount of allocated VNFs, thereby, allowing for a certain level of resilience.