1. What is the size of an ARP packet when the protocol is IPv4 and the hardware is Ethernet? 2. Distinguish between communication at the network layer and communication at the data-link layer. 3. What is the role of the address field in a packet traveling through a datagram network? 4. What is the role of the address field in a packet traveling through a virtual circuit network? 5. How do guided media differ from unguided media? 6. What is the function of the twisting in twisted-pair cable? 7. What is refraction? What is reflection? 8. What is the purpose of cladding in an optical fiber? 9. Name the advantages of optical fiber over twisted-pair and coaxial cable.