On demand QoS with a SDN traffic engineering management (STEM) module

Software Defined Networking (SDN) allows new approaches to provide Quality of Service (QoS). In legacy networks, strict QoS guarantees often result in bandwidth over-provisioning. Then, QoS enforcement either consumes too many resources, or is not flexible enough. We present a solution to provide QoS based on the creation of on-demand MPLS tunnels with guaranteed bandwidths across an SDN network. We introduce an SDN Traffic Engineering Management (STEM) module that interacts with the northbound applications to satisfy their requests to forward QoS-guaranteed traffic flows. STEM delegates the path selection to a Path Computation Element (PCE), and the path enforcement to an SDN controller. We rely on a stateful PCE to record the attributed resources and estimate the remaining network capacity, avoiding overloading the network with monitoring traffic. Upon STEM requests, the SDN controller enforces the QoS policy in the data plane. User flows are aggregated into MPLS tunnels and packets are labeled with a priority depending on the flow effective bandwidth. We highlight the shortfalls of several material and software OpenFlow compatible switches and detail an implementation based on a pica8 switch to overcome them. The experimental results demonstrate that this solution efficiently enforces bandwidth sharing in SDN networks.