Flow control is a function that prevents network congestion by ensuring that _( )_ do not overwhelm_( )_ with data.There are three commonly used methods for handling network congestion._( )_is used by network devices to temporarily store bursts of excess data in memory until they can be processed._( )_ are used by receiving devices to help prevent their buffers from overflowing._( )_ is a flow-control scheme in which the source device requires an acknowledgment from the destination after a certain number of packets have been transmitted.