Flow Control:
 If there is a fast sender at one end sending data to a slow receiver, then there must be flow control mechanism to control the loss of data by slow receivers.
 There are several mechanisms used for flow control such as increasing buffer size at receivers, slow down the fast sender, and so on.
 Some process will not be in position to accept arbitrarily long messages.
 This property leads to mechanisms for disassembling, transmitting and the reassembling messages.