This parameter, that is unique for all WRED classes, influences the way the Average Queue Size is calculated. The more the weight W q is increased the more the previuos values of the instantenous queue size are taken into account, and the system has more capacity to absorb burst. At the same time W q should not be too low otherwhise WRED can't react quickly to congestion. Some useful formulas are given in Figura2 . Thresholds are given in unit of packets.
All formulas have to be taken as a starting point for subsequent tuning.
The laboratory layout is summarized in Figure3 . The router configuration is summarized in Router-Config . The bandwidth available in the bottleneck link was divided into two groups. For bandwidth sharing the mechanism of CB-WFQ was enabled on the output interface. To achieve relative differentiations within the TCP group the WRED mechanism was enabled.