An apparatus, method, and storage medium for testing a network. A traffic generator may generate and transmit test traffic including a plurality of packet streams associated with a plurality of flow control groups. A traffic receiver may receive flow control packets from the network. Flow control logic may generate traffic class state data indicating a paused/not paused state for each of a plurality of traffic classes in accordance with the received flow control packets. A conversion table may map the traffic class state data into flow control data indicating a paused/not paused state for each of the plurality of flow control groups. The traffic generator may be configured to stop transmission of all packet streams associated with paused flow control groups in accordance with the flow control data.