$9\mathrm{.}12$ A packet$-$switching network is using a virtual circuit to transmit data from the

source to the destination node. In a given instance of data transmission, a message

of size $56$ octets is to be transmitted from node $x$ to node $Y.$ The virtual circuit

designed has $3$ intermediate nodes, $a,b,$ and $c.$ Each packet in the network has a

$4-$octet header that contains the control information. Determine the time of trans$-$

mission of the message sent from $x$ to $Y$ in each of the following cases:

a$.$ The entire message is sent as a single packet.

b$.$ The message is sent by dividing it into two packets.

c$.$ The message is sent using $7$ packets.

d$.$ The message is sent using $14$ packets.

What conclusion can you draw from the above observation? Assume that the trans$-$

mission time in each hop is the same.