FRACTaL: FEC-based rate control for RTP

We propose a new rate control algorithm for interactive real-time multimedia traffic, the FRACTaL algorithm. In our approach, the endpoint sends Forward Error Correction (FEC) packets not only for better error-resilience but also to probe for available bandwidth. The sender varies the amount of FEC to meet the sending rate calculated by the congestion control without changing the media rate. We evaluate our proposal in an emulated networking environment, using a set of reference test scenarios and compare it to the SCReAM congestion control algorithm. We find that FRACTaL performs better than SCReAM when competing with TCP flows, i.e., it is able to obtain its "fair" share. In other (non-TCP) scenarios, it achieves lower loss rates at comparable path utilization and queuing delay, i.e., FRACTaL delivers better and consistent media quality.