QOS based multicast communications

In a distributed multimedia integration environment, there is a need for transmission control methods based on real-time communication protocols, that provide a relative quality of service (QOS) to allow a variety of receiving capacities for group members and their requests and that provide a dynamic QOS to cope with temporary CPU overload and network congestion. Therefore, this study proposes a cooperative control method for end-to-end QOS control at a transport layer and for point-to-point control at a network layer. The former is mainly a set of flow-monitoring and flow-adjusting functions, and the latter a set of flow-control functions. The flow-adjusting functions provide in-depth evaluation of (1) the characteristics of the transmission data, (2) end-to-end network performance, and (3) the requirements of receiver applications. The appropriate QOS levels and flow control methods are then determined on the basis of the results.