The Guarantees of QoS for Multimedia Streams Based on Adaptive Session
Zhang Zhan · Chinese Journal of Computers · 2000
The guarantees of quality of service (QoS) is a key issue for continue multimedia streams in distributed multimedia computer systems. The QoS required by most multimedia streams is in a set or range, [ QoS min , QoS max ]. For example, when video streams are transmitted on network in a video conference system, theimage frame rate of QoS can be set [15 frame/second, 25 frame/second]. Computer systems and network systems must allocate enough resources such as CPU, I/O, memory and bandwidth to guarantee the QoS. These resources are dynamic variations in availability e.g. bandwidth in Internet during multimedia streams transmission. In detail, the CPU, I/O and memory resources in computer systems are dynamic variations in availability with the number of processes and threads and the bandwidths in network systems are dynamic variations in availability with the amount of communications among nodes. The adaptive session is defined in this paper. It can dynamic adjust its QoS in [ QoS min , QoS max ] by PID to adapt the variations in resource availability. It can adapt QoS higher or better when there are more available resources in systems, and it can adapt QoS lower or worse when there are little available resources. Thus, it not only meets the QoS required bout also improves the useful of resources.