Decomposition-based VNF placement algorithm in TDM-WDM-based optical aggregation network

In this paper, we consider the design of an optical aggregation network with network edge functions virtualization in order to reduce network cost. Here, an optical aggregation network connects a server accommodating virtual network functions (VNFs) with optical line terminals (OLTs) via a time-division-multiplexing (TDM)-based point-to- multipoint (P2MP) wavelength path to aggregate traf­fic from access networks. Each VNF must be placed on an adequate server in consideration of the efficiency of wavelength paths to reduce network cost. How­ever, existing VNF placement algorithms determines VNF placement without considering the efficiency of P2MP wavelength paths, which deteriorates network performance and increases network cost. To solve the problem, VNF placement must be carried out so that a P2MP wavelength path can be efficiently shared by multiple OLTs for reducing network cost. For this purpose, we propose a VNF placement algorithm, called decomposition-based VNF placement algorithm (DVA), in a TDM wavelength-division-multiplexing (WDM)-based optical aggregation network. The DVA can find approximate solutions of sufficient quality with practical computation time.