Dynamic Management of QoS for Multimedia Multicasting

The interaction between multicasting and real-time multimedia streams poses various new and interesting problems in research on communication protocols and architectures. For example, display systems of heterogeneous users in the same session may have different or even varying latency, display resolution, and/or processing capabilities. In this paper, we propose a receiver-oriented resource reservation mechanism, called dynamic management of QoS with priority (DMQP), for multimedia multicasting over the Internet that provides QoS guarantees with service differentiation for heterogeneous users. In the DMQP protocol, a real-time application requests QoS by specifying a range of acceptable bandwidth values and tolerable delay durations as opposed to rigid QoS criteria. The network strives to reserve resources for the application within its bandwidth range. In addition, service differentiation is achieved by classifying the real time applications (or end- users) into normal users and prioritized users. When the number of end-users increases, the new end-users are not simply rejected. Instead, all nodes, including receiver node(s), sender node(s) and intermediate node(s), readjust their reserved resources dynamically to admit more end-users, as long as their minimum bandwidth requirement is met. By treating the bandwidth requirements as ranges instead of a rigid value, DMQP provides the flexibility needed for operation in the dynamic Internet environment. It has the significant benefit of allowing more flexible sharing of available resources among applications. We have conducted simulations to evaluate the performance of the proposed mechanism. Our simulation results strongly validate our claim.