The mechanism of adapting RED parameters to TCP traffic

Random Early Detection (RED) can stabilize the queue within a given target range and thus 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 and 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 stabilize the queue and maintain high link utilization in a wide variety of network conditions. Keywords-RED; Congestion Control; Parameter tuning; Control theory