A. Answer each question briefly, but completely. When computing an answer, make sure to show how you arrived at your answer. For the hands-on portions, follow the directions but make sure to take a screen shot of your results and paste into your submitted document. You may need to Google some of the question topics. 1. How many layers are defined in OSI model? List them from top to bottom. 2. How many layers are defined in TCP/IP model? List them from top to bottom. 3. How many bytes are used for a MAC address? How many bytes are used for an IPv4 address? What about an IPv6 address? How many bytes are used for a port number? 4. Comparing the star topology and the bus topology in constructing a LAN, which one is better? Why? 5. Assume seven devices are arranged in a mesh topology. How many cables are needed? How many ports are needed for each device? 6. When connecting devices in a network, you need a switch. When do you need a router? 7. What is encapsulation and de-encapsulation? How is it used in a network? 8. Assume that the number of users of the Internet at the beginning of 2015 (January 1) is 250 Million. If the growth of users increases 15% per year, how many users will be using the Internet at the beginning of 2021 (January 1) 9. In the TCP/IP protocol suite, the Network layer is primarily responsible for what tasks? Name the main protocols that function at the Network layer. 10. Assume we need to download text documents at the rate of 500 pages per second (each page is 24 lines with 80 characters per line (8 bits per character)). What is the required bit rate of the channel?