communications, protocol The collection of techniques used

in serial communications to stop the sender sending data until

the receiver can accept it. This may be either software flowcontrol or hardware flow control. The receiver typically

has a fixed size buffer into which received data is written

as soon as it is received. When the amount of buffered data

exceeds a "high water mark", the receiver will signal to the

transmitter to stop transmitting until the process reading the

data has read sufficient data from the buffer that it has

reached its "low water mark", at which point the receiver

signals to the transmitter to resume transmission.