Virtual network embedding in software-defined networks

Research on network virtualization has been active for a number of years, during which a number of virtual network embedding (VNE) approaches have been proposed. These approaches, however, neglect important operational requirements imposed by the underlying virtualization platforms. In the case of SDN/OpenFlow-based virtualization, a crucial example of an operational requirement is the availability of enough memory space for storing flow rules in OpenFlow devices. In this paper, we advocate that VNE must be performed with some knowledge of the underlying physical networks, otherwise the deployment may suffer from unpredictable or even unsatisfactory performance. Considering SDN/OpenFlow-based physical networks as an important virtualization scenario, we propose an approach based on VNE and OpenFlow coordination for proper deployment of virtual networks (VNs). The proposed approach unfolds in the following main contributions: (i) a virtual infrastructure abstraction that allows a service provider to represent the details of his/her VN requirements in a comprehensive manner; (ii) a privacy-aware compiler that is able to preprocess this detailed VN request in order to obfuscate sensitive information and derive computable operational requirements; and (iii) a model for embedding requested VNs ensuring their feasibility at the physical level. The results obtained through our evaluation demonstrate that taking such operational requirements into account, as well as accurately assessing them, is of paramount importance to ensure the correct behavior of VNs hosted on top of the virtualization platform.