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Flow Control Types (Transmission Control over network)
During Transfer of data, a high speed computer is generating data traffic a lot faster than the network device can handle in transferring to destination, so single gateway or destination device can not handle much amount of traffice that is called "Congestion".
The Technice is used to control the data transfer when we have congestion, when a network device receive a data it stores in memory section and then trasfer to next destination this process called "Buffering".
Whereas Windowing is used for flow control by the Transport layer.
Say the sender device is sending segments and the receiver device can accomodate only a fixed number of segments before it can accept more, the two devices negotiate the window size during the connection setup. This is done so that the sending device does'nt overflow the receiving device's buffer.
Also the receiving device can send a single acknowledgement for the segments it has received instead of sending an acknowledgement after every segment received.
Also, this window size is dynamic meaning, the devices can negotiate and change the window size in the middle of a session. So if initially the window size is three and the receiving device thinks that it can accept more number of segments in its buffer it can negotiate with the sending device and it increase it to say 5 for example.
Windowing is used only by TCP since UDP doesn't use or allow flow control.