In data communications, the process of adjusting the flow of data from one device to another, in order to ensure that the receiving device can handle all of the incoming data, is called flow control. It is particularly important where the sending device is capable of sending data much faster than the receiving device can receive it. Flow control can be implemented in hardware and software, or a combination of both.

1. Data Link Layer regulates the flow of data so that receivers are not swamped by fast senders.

2. At the receiver, incoming data must be checked and processed before being used, this takes time.

3. Flow control allows the receiver to tell the sender to reduce the number of frames it is sending or stop sending completely since it cannot cope with the sender’s current sending speed.