Proportional Rate Reduction for TCP
Packet losses increase latency for Web users. Fast recovery is a key mechanism for TCP to recover from packet losses. In this paper, the authors explore some of the weaknesses of the standard algorithm described in RFC3517 and the non-standard algorithms implemented in Linux. They find that these algorithms deviate from their intended behavior in the real world due to the combined effect of short flows, application stalls, burst losses, ACKnowledgment (ACK) loss and reordering, and stretch ACKs. Linux suffers from excessive congestion window reductions while RFC3517 transmits large bursts under high losses both of which harm the rest of the flow and increase Web latency.