(c) A message of length 3200 bits is to be sent on a wide area network (WAN) with 3 hops. Each link in the network has a maximum capacity equal to 9600 bps. Data is sent on the network by using fixed packet size of 128 bytes. Assuming the propagation delay per hop is 0.002 s and the call set-up time is 0.1s, (1) calculate the end-to-end delay incur to transmit the whole message on circuit switched network; (4 marks) (11) calculate the end-to-end delay incur to transmit the whole message on virtual circuit packet switching network; and (6 marks) (111) discuss whether it is useful to use flow control in both of the above networks or not. (2 marks) (c) A message of length 3200 bits is to be sent on a wide area network (WAN) with 3 hops. Each link in the network has a maximum capacity equal to 9600 bps. Data is sent on the network by using fixed packet size of 128 bytes. Assuming the propagation delay per hop is 0.002 s and the call set-up time is 0.1s, (1) calculate the end-to-end delay incur to transmit the whole message on circuit switched network; (4 marks) (11) calculate the end-to-end delay incur to transmit the whole message on virtual circuit packet switching network; and (6 marks) (111) discuss whether it is useful to use flow control in both of the above networks or not. (2 marks)