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2) (30 points)  Consider a communication network with the following architecture: Host X is connected to a host Y via two communication links with transmission bit rates R1 = R bit/s and R2 = 4 R bit/s. That is, there is one router between host X and host Y.  Each communication link has a distance (length) of d meters with a propagation speed of s meters/second. The router interconnecting the communication links has unlimited buffer capacity and negligible nodal processing delay. In the following sub-problems a), b), and c), we examine the transmission of a file of size F bits with different transmission protocols over the described network architecture.  Aside from our examined transmission of the file of size F bits, there are no other traffic flows in the considered network. Drawing a labeled separate space-time diagram for each of the following parts a), b), and c) is required in order to receive credit. a) Consider message switching, i.e., the entire file is transmitted as one large packet.  How long does it take to transmit the file, i.e., to transfer the complete file from host X to host Y? b) Consider packet switching, i.e., the file is broken up into packets, each packet with P information bits, i.e., there are F/P packets (whereby we assume that F/P is an integer).  Packet header bits are negligible.  Consider packet transmission without window-based flow congestion control, i.e., the client host can send an unlimited number of packets into the network. How long does it take to transmit the file? c) Consider packet switching, i.e., the file is broken up into packets, each packet with P information bits, i.e., there are F/P packets (whereby we assume that F/P is an integer).  Packet header bits are negligible. Consider packet transmission with a window-based flow congestion control with a window size of one packet, i.e., the client host can send only one packet into the network before it has to stop to wait for an acknowledgement from the server. There are no packet losses in the network, and acknowledgements have negligible transmission delay (but incur the propagation delays).  How long does it take to transmit the file?  

3) (25 points)  Suppose you want to start an EEE 459 study group, complete with its own domain name (459study.net), web server, and five workstations. Suppose you have the following setup: primary authoritative DNS server with host name dns1.459study.net and IP address 45.45.59.1, secondary authoritative DNS server with host name dns2.459study.net and IP address 45.45.59.2, web server with host name www.459study.net and IP address 45.45.59.3, and workstations ws1.459study.net with IP address 45.45.59.11,ws2.459study.net with IP address 45.45.59.12,ws3.459study.net with IP address 45.45.59.13,ws4.459study.net with IP address 45.45.59.14, andws5.459study.net with IP address 45.45.59.15. a) What information will you need to give to a registrar?Where will the registrar insert this information? b) What information will you need to store on your authoritative DNS servers?

2. (11 pts) Given the sets U = {1, 2, 3, 4, 5}, A = {1, 2, 3, 5}, B = {1, 3, 4}, C = {3, 5}. Find the following. Show your work for anything problems that require more than one set to do so. a. A – C  b.

12. (10 pts) The following involve premises from Lewis Carroll. Write each premise in the if… then form and then write each premise in symbols for parts a to c, and give a conclusion that yields a valid argument. Let p = it is a dog. q = it loves music. r = It runs around when a song is played. s = it will scratch its ears.   a. One who does not run around when a song is played does not love music. ___________ b. No dog will scratch its ears. ______________________________________________ c. Whoever runs around when any song is played will scratch their ears._______________ d. Give a conclusion (in the context of this word problem) that yields a valid argument.

10. (10 pts) Use (only) the truth table to determine whether each argument is valid or not. Please assign your variable to each statement you use and rewrite any statements with those symbols before you show the truth table.   Elijah likes to watch Korean dramas or Sophia takes selfies. Elijah does not like to watch Korean dramas. Therefore, Sophia takes selfies.

4. (8 pts) Use a Venn diagram to shade the set

9. (6 pts) Draw a circuit representing the following statement. Do not simplify.

8. (7 pts) Find the truth value of the statement. Assume that p is true, and q and r are false. Show your work.  

11. (6 pts) Use the Euler Diagram to decide whether each argument is valid or not. Be sure to label on your diagram to support your answer.    If you are a celebrity, you have no time to sleep. That man has no time to sleep.   _____________________ That man is a celebrity

Instructions for Set Up: 1. Set the camera up so that it shows you seated (including your face and hands) and your entire work area simultaneously.  2. Next: Show both sides of all your blank papers to the camera. Do not use a notebook as you cannot show all the pages. You may use both sides of the paper as long as both sides were originally blank.  Show the face of your calculator to the camera. Any physical calculator is allowed. Show the face of your phone to the camera and place it face down on your workspace in view of the camera.