Any congestion control mechanism has two primary goals – to fill the pipe and to do no harm to other flows in the network. These two goals conflict with eachother – the former requires aggressiveness, whereas the latter requires caution. Traditional approaches use the same mechanism (the sending rate) to achieve these two conflicting goals. For example, TCP cautiously probes for bandwidth using slow-start, starting with a small initial window and then ramping up, in order to fill the pipe. As a result, it often takes flows several round-trip times to fully utilize the available bandwidth. RC3 simply decouples these two goals by sending additional packets from the flow using several layers of low priority service, to fill the pipe, while TCP runs as usual at higher priority. It can therefore, quickly take advantage of available capacity from the very first RTT to achieve near-optimal throughputs and smaller flow completion times while preserving TCP-friendliness and fairness. In common wide-area scenarios, RC3 results in a 40% reduction in average flow completion times, with strongest improvements – more than 70% reduction in flow completion time – seen in medium to large sized (100KB – 3MB) flows.