1. A method for abating network congestion in a network of nodes connected via a network interconnect, each node connected to a local controller, each of a plurality of the local controllers connected to a supervisory controller via an independent network connection that is independent of the network interconnect, the method comprising: determining at the supervisory controller whether the network is congested based on information received from the local controllers via the independent network connection; upon determining that the network is congested, sending from the supervisory controller to each local controller via the independent network connection an indication that the network is congested; and upon receiving at a local controller an indication that the network is congested, limiting a rate at which packets are injected into the network by nodes controlled by the local controller wherein each node is connected to the network via a network interface controller and the limiting of the rate of injection of packets includes the local controller signaling the network interface controller of a device to effect the limiting of the rate of injection of packets and wherein the local controller signals the network interface controller using pulse width modulation indicating a portion of a period during which injection of packets is prohibited.