Applications with multiple parallel flows: Assessing their unfair advantage with proportional fair sharing TCP

We seek to understand proportional fairness in equilibrium in the presence of both applications with multiple flows (MFAs) and traditional applications with single flows (SFAs). Proportional fairness is shown to be applicable to TCP variants such as TCP Reno, TCP Vegas, and FAST TCP. We consider the competing scenario where an SFA with proportionally fair sharing TCP is competing with an MFA that invokes a number of parallel flows, also with proportional fair sharing TCP. We present analytical results for a linear network, and show the extent of the quantitative gain of an MFA can over an SFA regardless of whether it is connecting the far end of a linear network or just the adjacent nodes.