Reference reading: [Kurose] Chapter 1, Chapter 2 Problems: 1. [10 pts] The Internet is divided into network edge (end systems) and network core (routers). Describe the main functionality at network edge and network core, respectively. 2. [10 pts] What advantage does a circuit-switched network have over a packet-switched network, and vice versa? 3. [10 pts] What are two reasons for using layered protocols? What is one possible disadvantage of using layered protocols? 4. [10 pts] Describe the main functions provided by each of the five layers of the TCP/IP Internet protocol stack. 5. [10 pts] A system has an n-layer protocol hierarchy. Applications generate messages of length M bytes. At each of the layers, an h-byte header is added. What fraction of the network? bandwidth is filled with headers? 6. [10 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)