Dynamic Resource Management for Continuous Media Traac over Atm Networks

Real-time continuous media traac, such as digital video and audio, is expected to comprise a large percentage of the network load on future high speed packet switch networks such as ATM. A major feature which distinguishes high speed networks from traditional slower speed networks is the large amount of data the network must manage. For eecient network usage, traac control mechanisms are essential. Currently, most mechanisms for traac control (such as ow control) have centered on the support of Available Bit Rate (ABR), i.e., non real-time, traac. With regard to ATM, for ABR traac, two major types of schemes which have been proposed are rate-control and credit-control schemes. Neither of these schemes are directly applicable to Real-time Variable Bit Rate (VBR) traac such as continuous media traac. Traac control for continuous media traac is an inherently diicult problem due to the time-sensitive nature of the traac and its unpredictable burstiness. In this study, we present a scheme which controls traf-c by dynamically allocating/de-allocating resources among competing VCs based upon their real-time requirements. This scheme incorporates a form of rate-control, real-time burst-level scheduling and link-link ow control. We show analytically potential performance improvements of our rate-control scheme and present a scheme for buuer dimensioning. We also present simulation results of our schemes and discuss the tradeoos inherent in maintaining high network utilization and statistically guaranteeing many users' Quality of Service.