Improving end-to-end performance by active queue management

Active queue management (AQM) schemes have motivated many researchers to investigate more effective methods to control network congestion. Most AQM schemes are evaluated by their designers on the basis of router-centric metrics, such as queuing delay, link utilization and packet drop ratio. These metrics are important to network operators but they may not reflect the quality of service delivered to end-users. In this paper we propose a method aimed to provide users with better services in terms of end-to-end delay and packet loss ratio. The method captures a significant traffic increase at an early stage and signals TCP sources to slow down. In this way, TCP can quickly adjust the transmission rate, and thereby prevent overloading the network. In addition to RED, another two prominent AQM schemes, namely, random early marking (REM) and adaptive RED (ARED), are compared with the proposed method. Simulation results show that under various network loads and a range of network propagation delays, our method can achieve lower end-to-end delay and packet loss ratio, compared with all aforementioned schemes.