Optimal Delay-Aware Service Function Chaining in NFV

Network Function Virtualization (NFV) enables the networks to provide dynamic and agile services by decoupling the network functions from hardware. Resource allocation is one of the most important challenges in NFV-based networks to maximize the providers' profile while satisfying customer requirement. End-to-end delay is one of the requirements that have got little attention in the literature. In this paper, we formulate the VNF embedding problem subject to delay constraint as a MINLP problem. In this formulation, the objective is to maximize the provider's profit such that the constraints of the nodes' capacity (i.e., memory, CPU, and storage), the links' capacity (i.e., bandwidth), the end-to-end delay threshold, and required resources (i.e., memory, CPU, and storage) for each instance are satisfied. This formulation can be used to analyze the effect of system parameters on the objective. The problem is solved optimally by the SCIP optimization tool. The simulation results verify our proposed model and the solvers optimal solution.