Utilization-Based Congestion Control

Abstract

Traditional connection oriented protocols like TCP NewReno perform poorly over wireless links. The problem lies in their design assumptions based on loss based congestion control. Various modifications to loss based congestion control schemes have so far been proposed to overcome the issue. In addition, the comparatively newer family of delay based congestion control mechanisms like Caia-Hamilton Delay (CHD), offer effective solutions for wireless link loss. All these approaches aim at improving the performance of the target connection without considering the overall network condition. Therefore, when co-existing with the conventional loss-based congestion control, the performances suffer severely. Furthermore, for delay based schemes, it is not possible to determine the optimum value of the queuing threshold intuitively. In this paper, we propose a new end-to-end congestion control mechanism that we name as Utilization-based Congestion Control (UCC) in order to overcome the above problems. UCC provides a solution based on the utilization at the bottleneck link. It is free from critical parameters like queuing threshold and is friendly to other flows over wireless links when deployed together. Simulation results show that over wireless links, (i) UCC can yield a performance improvement of 150% or more compared to conventional loss-based schemes and (ii) it is friendly to conventional loss-based congestion controls .