5. [10 pts] What are the four sources of nodal delay? Describe each one in detail. 7. [20 pts] Suppose there is exactly one packet switch between a sending host and a receiving host. Assume each link has a distance 2, 500 km with propagation speed 2.5 * 108 m/s. Link 1 has a transmission rate 1 Mbps and Link 2 has a transmission rate 2 Mbps. Assuming that the switch uses store-and-forward packet switching, what is the total end-to-end delay to send a 512-byte packet? (Ignore queuing and processing delay. Note: bps = bit per second, 1 byte = 8 bits) 8. [10 pts] What is the benefit of laying in network design. Describe the five Internet protocol stack in detail