Extended Queue Management Backward Congestion Control Algorithm

Abstract

Network Congestion is a major problem with respect to the Internet. The Active Queue Management algorithms (AQM) are used to reduce congestion, and in this paper, a new AQM algorithm is proposed called as Extended Queue Management Backward Congestion Control Algorithm (EQMBCCA). This is an extended version of the QMBCCA, which has been proposed earlier by us. QMBCCA makes use of Internet Control Messaging Protocol (ICMP) Source Quench (ISQ) notifications and also the CE (Congestion Experienced) bit whenever the average queue size crosses minimum threshold value. EQMBCCA introduces a configurable intermediate threshold value IntThres between the minimum and maximum values and generates ISQ signals only if the congestion crosses the threshold value. Therefore the generation of ISQ messages is significantly reduced here. There is also reliability since CE bits are set in the packets once congestion occurs. The proposed algorithm is compared with the Queue Management Backward Congestion Control Algorithm (QMBCCA) in terms of Gain in Goodput, Loss percentage and ISQ traffic for FTP flows. It is found that the performance of EQMBCCA is almost equal to that of QMBCCA and there is a significant reduction in the ISQ traffic in the reverse direction.