Abstract

The congestion control mechanisms used in TCP have been the focus of numerous studies and have undergone a number of enhancements. However, even with these enhancements, TCP connections still experience alarmingly high loss rates, especially during times of congestion. The IETF has addressed this problem by advocating the deployment of active queue management mechanisms, such as RED, in the network. While RED can potentially improve packet loss rates, we show that its effectiveness is highly dependent upon its operating parameters. In fact, in cases where these parameters do not match the requirements of the network load, the performance of the RED gateway can approach that of a traditional drop-tail gateway. To alleviate this problem, we propose and experiment with a self-configuring active queue management mechanism which can significantly reduce loss rates across congested links. When used in the network, this mechanism can effectively reduce packet loss while maintaining high link utilizations under the most difficult scenarios. Keywords: Congestion control, Internet, TCP, RED, queue management 1

Citations