There are two hosts A and B in a packet-switched network, interconnected by three routers, as illustrated in the figure below. Each link is annotated with link capacity (above) and propagation delay (below). Each router follows the store-and-forward model to process packets, and has a queue that can hold 5 packets for each direction. If the queue is full and a new packet arrives at the router, the new packet is dropped. (Note: Once a packet starts being transmitted, it will be removed from the queue. Thus, there may be 6 packets in the router at any given time point). Suppose the network is empty and all the routers are idle.

Calculate the worst-case end-to-end delay for (Hint: not all the queues will be full): a) For Host As 1500 bytes packet to reach Host B b) For Host Bs 1500 bytes packet to reach Host A

B