Abstract: Congestion control method in which a source switch measures a number of calls sent by the source switch to a congested switch that are rejected by the congested switch. In response to a report from the congested switch identifying its level of congestion, the source switch blocks calls destined for the congested switch based upon the measured number of rejected calls. A given switch may act as both a congested switch and a source switch. The switch routes call traffic to one or more switches in a network; the switch is a source to those other switches. At the same time, the same switch may receive call traffic from the other switches. The switch may be a congested switch and the other switches may be source switches.