Differential equation models of flow-size based priorities in internet routers

Abstract

Simulation studies have shown that providing priority to short-flows in internet routers can dramatically reduce their mean delay while having little impact on the long-flows that carry the bulk of internet traffic. In this paper, we present simple differential equation models (commonly referred to as fluid models) that can be used to analytically quantify this observation. Our model is at the connection-level where file arrivals and departures are described using differential equations, while ignoring the packet-level effects. We demonstrate that network performance can be enhanced significantly by giving priorities to short-flows without seriously affecting the throughput of long-flows.