Hierarchical scheduling for multiple classes of applications in connection-oriented integrated-service networks

Multiple classes of conventional and multimedia applications are expected to be supported by the emerging connection-oriented integrated-service networks, where best-effort flows and quality-of-service (QoS) flows co-exist. We propose a novel two-level hierarchical scheduling algorithm, which provides an integrated, simple scheme to distribute the link bandwidth among a dynamic set of flows in the network, such that (1) every QoS flow always receives a bandwidth which guarantees the required quality of service and (2) after the requirements of the QoS flows are satisfied, the rest network bandwidth is fairly shared among all best-effort and soft QoS flows. We extend our hierarchical scheduling algorithm to support both bursty and non-bursty flows. We also discuss the techniques which make the throughput of a QoS flow to be constantly lower bounded and/or upper bounded.