Using WMS log files as an indicator of QoS and application performance in on-demand streaming videos

When utilizing video streaming for professional purposes, the quality of service needs to be evaluated by the service provider. This is the case especially when the service must be available for a large number of customers with a wide range of network interfaces and terminal equipment. Service providers have usually information about network-level metrics. However, the problem is that conditions that appear similar in a networklevel may cause very different responses in an application level, and the other way round. In this article, we study how Windows Media Server´s log files can be used to evaluate the QoS of video transmission, and we also examine the application level performance based on the log files. The level of QoS affects user satisfaction and thus QoE, although the relationship between them may be complicated. Understanding how the application responds to deteriorated network conditions gives tools to evaluate also QoE. The examination is limited to on-demand streaming sessions in which UDP is used as a transport protocol.