Available bandwidth measurement in software defined networks

Software Defined Networking (SDN) is an emerging paradigm that is expected to revolutionize computer networks. With the decoupling of data and control plane and the introduction of open communication interfaces between layers, SDN enables programmability over the entire network, promising rapid innovation in this area. The SDN concept was already proven to work successfully in cloud and data center environments thus the proper monitoring of such networks is already in the focus of the research community. Methods for measuring Quality of Service (QoS) parameters such as bandwidth utilization, packet loss, and delay have been recently introduced in literature, but they lack a solution for tackling down the question of available bandwidth. In this paper, we attempt to fill this gap and introduce a novel mechanism for measuring available bandwidth in SDN networks. We take advantage of the SDN architecture and build an application over the Network Operating System (NOS). Our application can track the topology of the network and the bandwidth utilization over the network links, and thus it is able to calculate the available bandwidth between any two points in the network. We validate our method using the popular Mininet network emulation environment and the widely used NOS called Floodlight. We present results providing insights into the measurement accuracy and showing its relationship with the delay in the control network and the polling frequency.