Consider a scenario where two end hosts, denoted as A and B$,$ are connected by a link. The

length of the link is $9000$ kilometers, and data transmits between the hosts at the speed of

light, $3\backslash$times $108$ meters per second. The link capacity is $20$Mbps$.(35$ points$)$

$1.$ Calculate the time it takes for a single bit to traverse the distance between host A and

host B along the link. $(5$ points$)$

$2.$ Suppose we intend to transmit a file with a size of $10$MB from host A to host B$.$

Assuming that the transmission begins at time $0$ seconds, determine the time when

the last bit of the file leaves host A$.(5$ points$)$

$3.$ When the last bit of the file left host A$,$ has the first bit of the file been received by B$?$

Explain your answer by the relation between transmission delay and propagation

delay. $(5$ points$)$ Explain your answer by packet length in meters. $(5$ points$)$

$4.$ Following the above question, please calculate the time when B finishes receiving the

whole file. $(5$ points$)$

$5.$ Suppose we intend to transmit a file with a size of $0\mathrm{.}1$Mbits from host A to host B$,$

when the last bits of the file leave host A$,$ has its first bit been received by B$?$ Explain

your answer by the relation between transmission delay and propagation delay. $(5$

points$)$ Explain your answer by packet length in meters. $(5$ points$)$