Fast and Cost-Efficient Virtualized Network Function Placement Algorithm in Wireless Multi-hop Networks.

Network Function Virtualization (NFV) can lower the CAPEX and/or OPEX for service providers and allows the deployment of services quickly. The main challenge in the use of Virtualized Network Functions (VNF) is optimally placing them in the physical network in terms of deployment cost and resource consumption. The critical problem of VNF placement is inherently NP-hard and the available optimal solutions do not scale with respect to the network size. The problem of NFV placement is even more challenging in wireless networks as we are facing the issue of scarcity of BW due to the presence of interference. Therefore, this paper aims to solve the problem of VNF placement in wireless multi-hop networks by considering BW limitations and scalability. We tackle both issues at once by limiting the search space to the shortest paths. We search for the placement solution along shortest paths to minimize the BW consumption and at the same time reduce the search space to the nodes and links along the shortest path. The results are compared to a mathematical optimization model and a comparable heuristic model. They show that our proposed heuristic greatly decreases the execution time in comparison to the mathematical model and the alternative heuristic while keeping the acceptance ratio close to the optimal solution.