Date Completed: June 2009

In this Tech Report, we start by introducing the principles of congestion control and its importance in the stability of the Internet. We then move on to provide some background information on TCP’s congestion control algorithms as well as on Explicit Congestion Notification (ECN). Afterwards, we explain the concepts behind the major Active Queue Management (AQM) mechanisms and explore their designs. We conclude the report by stating our opinion regarding “fairness” and will reinforce our position by introducing the “re-ECN” initiative.