Low Extra Delay Background Transport (LEDBAT) is a new, delay-based congestion control algorithm that is currently under development in the IETF. LEDBAT has been proposed by BitTorrent for time-insensitive background traffic that otherwise would disturb foreground traffic like VoIP or video streaming. During previous evaluations the so called late-comer advantage has been discovered which makes a new starting LEDBAT flow predominant against already running LEDBAT flows. In this paper we evaluate different decrease schemes which have been proposed to solve this problem. We found that the proposed solutions come with a lower utilization, sometimes increased completion times and are much more sensitive to noise, which is contra-productive for the considered traffic class. Furthermore, we propose extensions to both evaluated schemes. We show that our approach can help to yield more quickly to higher priority traffic. We argue that a fair and equal share is not required for the specific traffic class LEDBAT is designed for. But it is important to address different application requirements in congestion control like LEDBAT as an approach for less-than-best effort background traffic.
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