Achieving end-to-end real-time Quality of Service with Software Defined Networking

Due to the distributed nature of the network protocols, the provisioning of end-to-end Quality of Service (QoS) in IP-based networks is a complex task. We argue that Software Defined Networking (SDN) delivers a key technology to improve QoS provisioning. The core idea of SDN is the establishment of a standardized interface between the control and forwarding planes, allowing a logically centralized controller to control each forwarding element in a unified way. This unified interface provides three key features of SDN: flexibility, a centralized view and programmability. In this paper we exploit these features to create an end-to-end real-time QoS communication service based on SDN. In particular, our concept allows to flexibly allocate each flow in a network to different priority queues in each hop along its way to optimize the resource usage while being able to keep the delay and bandwidth constraints. This concept can be used, for example, to realize a more fine granular access control for real-time communication services allowing potentially more flows to be accepted than with traditional QoS reservation concepts. For our concept, we introduce a deterministic network model using network calculus to compute the optimal paths for each flow through the priority queues. We validate our concept with a simulation based performance analysis for a selected network scenario. In this setting our concept improves the average link utilization from 30% to more than 60% compared to traditional QoS reservation concepts.