Enhanced congestion avoidance in network devices

A downstream network device in a switching system receives, via an ingress port, packets from an upstream network device in the switching system, and forwards the packets to determined respective egress ports via which the packets are to be transmitted. The downstream network device monitors respective congestion states of ones of the respective egress ports, and in response to determining that a particular egress port is congested, generates a flow control message to include an indication of the particular congested egress port and transmits the flow control message via the ingress port to the upstream network device to cause the upstream network device to modulate a flow of packets directed to the particular congested egress port, to reduce congestion at the particular congested egress port, without causing the upstream network device to modulate the flow of packets directed to other ones of the egress ports of the downstream network device.