Kalman Filter Based Congestion Controller

摘要

Facing burst traffic, TCP congestion control algorithms severely decrease window size neglecting the fact that such burst traffics are temporal. In the increase phase sending window experiences a linear rise which may lead to waste in hefty proportion of available bandwidth. If congestion control mechanisms be able to estimate future state of network traffic they can cope with different circumstances and efficiently use bandwidth. Since data traffic which is running on networks is mostly self-similar, algorithms can take advantage of self-similarity property and repetitive traffic patterns to have accurate estimations and predictions in large time scales. In this research a two-stage controller is presented. In fact the first part is a RED congestion controller which acts in short time scales (200 milliseconds) and the second is a Kalman filter estimator which do RTT and window size estimations in large time scales (every two seconds). If the RED mechanism decides to increase the window size, the magnitude of this increase is controlled by Kalman filter. To be more precise, if the Kalman filter indicates a non-congested situation in the next large time scale, a magnitude factor is calculated and given to RED algorithm to strengthen the amount of increase.