Consider a network of 3 interconnected computers X, Y and Z arranged on a line, where the link bandwidth (bit-rate) between X and Y is 5Mbps, the link bandwidth between Y and Z is 2Mbps and the one-way propagation delays are 10ms between X and Y and 20ms between Y and Z. (X and Z are not directly connected).
How long does it take for X to send a 3KB packet to Z (via Y) and for Z to fully receive that packet, assuming that Y must receive all bits of the packet before it starts sending any bits to Z? (This is “store and forward” transport)
(answer should be correct to one decimal place)