Research on QoS-Based Networks Node-State

The selection and collection of the node state information have great impact on the design complexity and performance of a QoS routing algorithm. Continuous-media traffic (e.g. audio and video) can tolerate some loss but has rigid delay constraints. Under this QoS constraint, the node-delay´s probability density function (PDF) is used to character the node state. The continuous-media traffic is in high burst. So the node-delay´s PDF is shaped into normal distribution through a filter algorithm. Analysis and simulation show that the tail probability of the normal distribution can be used to calculate the end-to-end packet loss rate approximately. Then the variance and mean value of the PDF can be controlled to calculate a proper packet loss rate to satisfy the QoS demand. So normal distribution is a simple, achievable and reasonable description