SplitBuff: Improving the interaction of heterogeneous RTT flows on the Internet

Today router buffers are sized according to the well-known Bandwidth-Delay Product (BDP) rule, which uses the average round-trip time (RTT) of flows traversing a router. The BDP rule not only leads to large queueing delays, but also imposes “one (buffer) size fits all” philosophy for flows exhibiting a large variation in RTT. When short and long RTT flows compete at a single buffer, they may adversely affect each other in throughput and delay. We propose SplitBuff, a scheme using which short RTT flows achieve low delay and long RTT flows achieve high throughput, without requiring any protocol modifications. With SplitBuff, a router splits a buffer into multiple buffers of varying sizes and maps flows onto these buffers based on their RTTs. We describe SplitBuff and evaluate its performance using extensive ns-2 simulations to demonstrate its effectiveness.