Flow control mechanisms ensure that a sender does not overwhelm a receiver by transmitting too much data too quickly. Buffering allows data to be temporarily stored until the receiver is ready to process it. Source quench messages are used in network protocols to inform the sender to reduce the rate of data transmission. Windowing controls the amount of data that can be sent before needing an acknowledgment, effectively managing the flow of data. Therefore, Buffering, Source quench messages, and Windowing are used for flow control.