Compensation Buffer Sizing for Providing User-Level QoS Guarantee of Media Flows

When transferred in a packet-switched network, the temporal structure of continuous media may be damaged by delay and delay jitter. Compensation buffering is a well-known method to absorb the delay jitter. However, added buffering increases the latency, which may degrade the interactivity between users. As delay and delay jitter are both perceived QoS parameters to users, changing compensation buffer size may result in completely opposite effect on user-level QoS. How to set the buffer size to provide both delay and delay jitter guarantee with preferable user-level QoS? To answer the question, we investigate the effect of buffer size on maintaining the temporal structure of media flows. By performing QoS mapping from network-level to user-level, we prove that there is an optimal buffer size to provide the optimal user-level QoS and obtain the optimal buffer size by differentiating approach. Experiment results validate our studies on the effect of the buffer size.