The mechanism of adapting RED parameters to TCP traffic

Random Early Detection (RED) can stabilize the instantaneous queue size at a router by controlling the average queue size within a given target. In this case, RED can achieve high throughput in the routers. However, the average queue size is quite sensitive to network scenarios and it is difficult to adapt RED parameters to changing network traffic. In this paper we use a previously developed dynamic model of TCP behavior together with a linear feedback model of TCP/RED to analyze and design a mechanism for RED parameter tuning in response to changing network conditions like traffic load, link capacity and round-trip time. Even though the values of four key RED parameters are determined by varying network conditions, they can be tuned independently without consideration of the interactions among these RED parameters. Simulation results show that this mechanism can keep the instantaneous queue size stable and maintain high link utilization in a wide variety of network conditions.