ERUF: early regulation of unresponsive best-effort traffic

We propose router mechanisms to regulate unresponsive best-effort traffic. By unresponsive traffic we mean flows that do not reduce their sending rate in response to congestion. The goal of the proposed mechanisms is to drop undeliverable packets as close to the periphery of the network as possible. The key ideas of our approach are: (1) edge routers keep track of incoming flows and their arrival rates; (2) core routers use random early detection (RED) for queue management and generate rate-limited source quenches on packet drops to advice sources to reduce their sending rates; and (3) edge routers snoop an source quenches passing through them and use them to control per-flow regulators. Regulators adjust their maximum sending rate using a multiplicative-decrease, additive-increase discipline. A decrease is triggered by the arrival of a source quench; an increase is triggered by non-arrival of source quenches for a time period. We examine the impact of these mechanisms for a variety of simulated network topologies and traffic patterns.