The available bit rate is an important service class for ATM networks because it provides a rate control mechanism that enables one to dynamically adjust the source rate to the amount of resources available in the network. We present an original design of an explicit rate based ABR algorithm: ERAQLES. It provides a dynamic evaluation of the level of available resources left unused in the network in presence of both CBR and VBR traffic. The evaluation and distribution functions used to obtain the explicit rate allocated to each individual source are computed with a novel distribution that controls the filling level of the ABR queue. The efficiency of the algorithm under various network configurations is shown to be excellent.