Virtual Network Function Placement with Function Decomposition for Virtual Network Slice

Virtual network functions (VNFs) are placed across the network to complete the required network performance of virtual network slice (vNS), and the placement of VNFs is flexible and problematic. Besides, a VNF can be decomposed into multiple sub-functions, and the same type of sub-function can be re-used by multiple VNFs. Therefore, the resources of subfunctions in different vNS requests can be shared and the cost of the substrate network is reduced. So, function decomposition makes the VNF placement problem more flexible and challenging. In this paper, we study the VNF placement problem with function decomposition for vNS, and formulate it as an integer linear programming (ILP) aiming to minimize the total cost of the substrate network. Then, an approach named Placement algorithm based on Function Decomposition (P-FD) is proposed to get a near-optimal solution of this problem. Finally, simulation results show that P-FD can achieve less total cost compared with algorithms in existing.