QTS: a QOS-guaranteed transport system for broad-band multimedia communications

We propose a quality-of-service (QOS)-guaranteed transport system (QTS), which offers various QOSs at the transport layer for broad-band multimedia communications. The QTS, composed of a bandwidth allocator and a transport protocol module, supports three classes of applications requiring different bit rates, delay sensitivity, and loss sensitivity. The bandwidth allocator intelligently manages the allocation of transport-layer bandwidth at the expense of imposing inevitable blocking of delay-sensitive application connections. The transport protocol module of the QTS performs rate-based flow control for delay-sensitive applications based on transfer rates predetermined by the bandwidth allocator. In addition, the module accomplishes error control only for loss-sensitive applications. As a result, by providing guaranteed rates and reducing the error control overhead, the QTS offers satisfactory bounded delays and jitter for delay-sensitive applications, while incurring minimal throughput degradation for loss-sensitive applications. Finally, we demonstrate the superiority of the QTS over transmission control protocol (TCP) via simulation results in terms of maximum and mean system delays and delay jitter.