2. Consider a link with data rate R bps and a propagation delay of d sec for every unit of distance (assume kilometers if you like); the two nodes at the ends of the link are separated by distance L. Data is packaged into uniform "frames" of size F bits which are then transmitted from source to destination. The destination node instantaneously "processes" each frame and generates an acknowledgement which is sent back to the source node; you can assume the acknowledgment is 0 bits in length (unrealistic but will simplify your answer). Write a formula for the time required to send a file of size 8 bits assuming each successive frame is transmitted only when an acknowledgement for the previous frame is received