A network adapter includes a receive (Rx) pipeline, a transmit (Tx) pipeline and congestion management circuitry. The Rx pipeline is configured to receive packets sent over a network by a peer network adapter, and to process the received packets. The Tx pipeline is configured to transmit packets to the peer network adapter over the network. The congestion management circuitry is configured to receive, from the Tx pipeline and from the Rx pipeline, Congestion-Control (CC) events derived from at least some of the packets exchanged with the peer network adapter, to exchange user-programmable congestion control packets with the peer network adapter, and to mitigate a congestion affecting one or more of the packets responsively to the CC events and the user-programmable congestion control packets.