We analyze the dynamic behavior of a single RED controlled queue interacting with a large population of idealized TCP sources, i.e., sources obeying the rules of linear increase and multiplicative decrease. The aggregate trac from this population is modeled in terms of the time dependent expected value of the packet arrival rate which reacts to the packet loss taking place in the queue. The queue is described in terms of the time dependent expected values of the instantaneous queue length and of the exponentially averaged queue length, for which we also derive a pair of di erential equations. This provides us with a complete model for the dynamics of the system which we use to explore transient and equilibrium behavior. The accuracy of the model is veri ed by comparison with simulated results.