MEASUREMENT AND PREDICTION OF NETWORK CHARACTERISTICS FOR ADAPTIVE VIDEO SERVERS

摘要

We present the extension of an adaptive distributed multimedia streaming server architecture (ADMS) towards a Quality of Service based network infrastructure. The key component of the extension is the distributed active network estimation and forecasting tool (DANEF). It is able to estimate, process and forecast bottleneck bandwidth, available bandwidth, delay, jitter and loss of a certain path between the streaming server and the requesting client. Using this information, the server node that offers the best QoS for a certain client is selected from a set of possible candidates. Active measurements are performed by sending ICMP packet trains and forecasts are performed by applying fast algorithms that need only small initialization sets. The accuracy of the measurements is achieved by applying an efficient and innovative filtering mechanism, the correctness of the forecasts is achieved by dynamically selecting the best fitting forecast model and by considering the forecast error of previous samples. We have compared DANEF to other already existing measurement tools like BProbe, Cprobe, Pathload, Pathchar and Network Weather Service. As can be found in the evaluation part of this paper DANEF is much better suited for estimating QoS characteristics in the context of multimedia streaming than the other 5 tools it has been compared to.