Multimedia feedback control in ATM local area networks

Abstract

Multimedia networking refers to the transfer of related audio, video, image and data streams among networked computers. A key problem in multimedia networking is the synchronization of audio and video streams to maintain their timing relationships. In addition, due to the large time--varying resource demands of real--time video, an automatic mechanism is needed to dynamically modify the video source output in order to track changing network traffic levels. We have developed a receiver--initiated feedback control scheme to allow video sources to respond to changing network conditions while maintaining synchronization with their associated audio streams. The receiver informs the sender about the current transmission quality, and the sender responds to this information by adjusting some transmission parameters which temporarily decrease video quality (if the receiver is reporting problems) or increase the video quality (if the receiver is reporting no problems but the quality is less than its target). We present simulation results which indicate that our feedback mechanism can help to maintain audio--video synchronization in Asynchronous Transfer Mode local area networks, as well as reduce the network traffic congestion which leads to glitches in the first place.