A cross-comparison between TCP and AQM algorithms: Which is the best couple for congestion control?

Abstract

Current Internet traffic is carried mainly by the Transmission Control Protocol (TCP), and the performance of the Internet depends strongly on how well TCP works. Detecting and mitigating the congestion is one of the main tasks of this protocol, in fact, different TCP versions are defined by their congestion control algorithm. Also, Active Queue Management (AQM) algorithms share the same goal of congestion mitigation with TCP, in particular, the most effective congestion control occurs when AQM and TCP work together. This paper presents a brief survey and a cross-comparison of the latest and most important TCP and AQM variants, then provides an evaluation of a different kind of performance (multiple Round-Trip Time, long delay, different congestion level, etc.) on the ns-3 network simulator over various types of environments. In a shared bottleneck, the choice of the TCP-AQM couple to adopt is crucial; we show that the results are not univocal, the “golden couple” depends on the performance that we want to boost and on the environment that we have to deal with.