Enhancing QoS for Delay-Tolerant Multimedia Applications: Resource Utilization and Scheduling from a Service Provider's Perspective

Emerging applications such as distance education and corporate training are examples of delay tolerant multimedia applications, where clients request the start of play back at a convenient time specified by (t+d
_i
) where t is the current time and d
_i
is the delay tolerance acceptable to client i. Such applications typically involve a Closed User Group (CUG) network that exhibits heterogeneous characteristics, where a Content Service Provider (CSP) disseminates multimedia content to geographically dispersed clients. Our research deals with the issue of maximizing rates (quality) at the clients while satisfying their delay tolerance with minimal additional resources. As a first step to this end, we have developed an optimization-based approach to determine the best quality that can be delivered to the clients through judicious placement of resources such as buffers and transcoders. Simulation results demonstrate the usefulness of exploiting client delay tolerance specifications for delivering enhanced Quality of Service (QoS) with little or no additional resources. By maximizing QoS to the clients with given resources, CSPs can (1) maximize the utilization of links (2) provide differentiated services to their clients, and (3) offer upgraded services to some clients (which may have a revenue implication). Our ongoing work deals with scheduling and admission control issues which would maximize profits for the CSP while satisfying the admitted clients' requirements with optimal resource utilization.