An experimental evaluation of LEDBAT++

Abstract

LEDBAT++ is the evolution of LEDBAT, a congestion control algorithm originally designed to provide less-than-best-effort transport on the Internet. LEDBAT++ aims to address a number of shortcomings present in LEDBAT, including late-comer advantage, latency drift, competition on equal grounds with best effort traffic in the presence of small buffers and difficulties experienced while measuring the variations on the delay.In this paper, we perform an experimental evaluation of LEDBAT++ using the Windows Server’s LEDBAT++ implementation. We find that while LEDBAT++ overcomes all the limitations identified in LEDBAT, the change introduced in LEDBAT++ to do so results in a performance penalty that prevents LEDBAT++ flows to seize all the available capacity when there is no competing traffic. We propose two simple modifications to the LEDBAT++ algorithm that would address the identified issues and reduce the penalty.