QoS guarantees based on end-to-end resource reservation for real-time video communications

The distributed multimedia system requires Quality of Service (QoS) guarantees in each entity within the system. The underlying transport network has to guarantee the network-level QoS, e.g., transfer delay, delay jitter and loss ratio. The video server has to have a mechanism to transmit the requested video stream in a real-time fashion, and the client must take care of the continuous and high-quality video presentation to users. To provide guaranteed QoS to users, sufficient system resources, i.e., network resource (bandwidth) and CPU resource (processor cycles) must be reserved. In a case when the network or CPU load is high, the multimedia system has to accommodate itself with the available resources. In this paper, we first investigate relationships among the video quality and the amount of CPU/network resources required to provide a real-time video communication. Then, we introduce the QoS control method which enables the effective resource usage and maximizes the provided video quality.