QTS - A QOS-GUARANTEED TRANSPORT-SYSTEM FOR BROAD-BAND MULTIMEDIA COMMUNICATIONS

In this paper, we propose a quality of-service (QOS)guaranteed transpo rt system (QTS), which offers various QOS's at the transport layer for broad-band multimedia communications, The QTS, composed of a bandwidt h allocator and a transport protocol module, supports three classes of applications requiring different bit rates, delay sensitivity, and lo ss sensitivity, The bandwidth allocator intelligently manages the allo cation of transport-layer bandwidth at the expense of imposing inevita ble 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 b andwidth allocator, In addition, the module accomplishes error control only for loss-sensitive applications, As a result, as will be shown, by providing guaranteed rates and reducing the error control overhead, the QTS offers satisfactory bounded delays and jitters for delay-sens itive 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 res ults in terms of maximum and mean system delays and delay jitter.