Consider a source computer (S) transmitting a packet of size 15000 bits to a destination computer (D) over a network of two routers (R1 and R2) and three links (L1, L2 and L3). L1 connects S to R1;L2 connects R1 to R2; and L3 connects R2 to D. Let each link be of length 100km. Assume signals travel over each link at a speed of 10^8 meters per second. Assume that the link bandwidth on each link is 100 Mbps. a. What is the propagation delay for L1? b. What is the total propagation delay from S to D? c. What is the transmission delay to put the packet onto L1? d. What is the total transmission delay from S to D?