Rate-Based QoS Control of Multiple Flows over a Real-Time OS

When multiple ows including continuous media streams are simultaneously sent from a computer, allocation and management of both processor capacity and network bandwidth need to be considered. We propose a framework of Quality of Service (QoS) management inside a sending host that controls execution of sending threads in consideration of utilization of processor capacity and network bandwidth. To distinguish from ows which require only best-e ort service, we call a ow which requires a speci c rate of service \reserved ow." To guarantee QoS of such reserved ow both in processorand network-intensive cases in a sending host, processor capacity reserve is allocated such that the rate of each reserved ow is attained and nonconforming data are policed before they are transmitted. Processor Capacity Manager and the network device driver exchange information in a cooperative manner to support the rate adaptive allocation of processor capacity reserve. In this paper, we describe design and implementation of our framework on RT-Mach. The results of performance evaluations demonstrate that our scheme performs well for full-duplex Ethernet. This research is conducted under the fund of Informationtechnology Promotion Agency, Japan (IPA).