Analysis of a fluid approximation to flow control dynamics

The authors consider a flow control mechanism that dynamically regulates the rate of data flow into a network based on feedback information about the network state. Such mechanisms have been introduced in a variety of networks, and have been advocated for future high-speed networks. The authors first model the flow control mechanism by a discrete-space stochastic process and define appropriate performance measures for transient and steady-state regimes. However, the model does not appear to be analytically tractable, and the authors study it through simulation. They then simplify it to a continuous-space deterministic (or fluid) model for which closed-form solutions can be derived easily. It is found that the analytical results for the fluid model agree well with the simulation results obtained using the discrete-space model. Both models explicitly consider delay of the feedback information, thus making them relevant for high-speed networks