1. Suppose two hosts, A and B, are separated by 20,000 kilometers and are connected by a direct link of R = 4 Mbps. Suppose the propagation speed over the link is 2.5 108 meters/sec. (a) Consider sending a file of 1,500,000 bits from Host A to Host B. Suppose the file is sent continuously as one big message. How long does it take to send the file, assuming it is sent continuously? (10 points) (b) Suppose now the file is broken up into 30 packets with each packet containing 50,000 bits. Suppose that each packet is acknowledged by the receiver (by sending a small size acknowledgement packet) and the transmission delay of an acknowledgment packet at the receiver is negligible. Finally, assume that the sender cannot send a packet until the preceding one is acknowledged. How long does it take to send the file? (10 points)