Flow control is the management of the flow of frames between two directly connected link-partners. To achieve flow control, you specify a flow control option that causes packets called Pause frames to be used as needed.
For example, link-partner A sends a Pause On frame to link-partner B when its receive buffers are nearly full. Link-partner B suspends transmission until it receives a Pause Off frame from link-partner A or a specified timeout threshold is reached. Thus, flow control can reduce or eliminate dropped packets due to overrun.