Control Plane for End-to-End QoS Guarantee: A Theory and Its Application

There is growing evidence that a new generation of potentially high-revenue applications requiring quality of service (QoS) guarantee are emerging. Current methods of QoS provisioning have scalability concerns and cannot guarantee end-to-end delay. For a theoretical fluid model, we derive four distributed rate and delay controls accounting for their bandwidth and end-to-end delay requirements while also allowing for multiple flow priorities. We show that two of them are globally stable in the presence of arbitrary information time lags and two are globally stable without time lags. The global stability in the presence of time lags of the later two is studied numerically. Under all controls, the stable flow rates attain the end-to-end delay requirements. We also show that by enhancing the network with bandwidth reservation and admission control, minimum rate is also guaranteed by our controls. By guaranteeing end- to-end delays, our controls facilitate router buffer sizing that prevent buffer overflow in the fluid model. The distributed rate- delay combined control algorithms provide a scalable theoretical foundation for a QoS-guarantee control plane in current and in "clean slate" IP networks. To translate the theory into practice, we describe a control plane protocol facilitating our controls in the edge routers. The stability and performance of discrete time versions of our controls are demonstrated numerically in a widely spanned real network topology.