IAPI: An intelligent adaptive PI active queue management scheme

Internet traffic is bursty and unpredictable. It is therefore important to control congestion to protect users from traffic surges in a way that is efficient, stable and robust. Research has shown that active queue management (AQM) has the potential to control congestion such that these requirements are met. However, despite much work and many published proposals of AQM algorithms, a satisfactory solution is still unavailable. In this paper, an intelligent adaptive PI controller (IAPI) is proposed as a new AQM scheme, and its design details are presented. Setting of parameter values for IAPI is provided based on previous studies on PI and additional empirical studies. The performance of IAPI is evaluated by simulations and the results demonstrate that it is stable and robust under various scenarios including cases involving different types of background traffic (UDP and HTTP) and a case involving a multiple bottlenecks. Its superiority over other AQMs is also demonstrated.