3. Suppose that Bob sends 18 back-to-back packets, each of length L bits, to Alice over 5 links (shown below). Suppose that the transmission rate of each link is 2L bits/sec (bps). Consider the routers to be store-and-forward routers. What is the end-to-end delay of sending all packets to Alice (i.e., when does the last bit of the last packet arrive at Alice since Bob starts transmitting)? Note, consider only the transmission delay that occurs in sending packets. Show the steps used for derivation in detail. (6 points) Bob Alice 2L bps 2L bps 2L bps 2L bps 2L bps