Critical Thinking Questions:1) What is the purpose of a Network Interface card (NIC). On what layer of the OSI model isit based. Why?2) Does a computer need to use both MAC address and an IP address? Justify your answer.Download and install the Wireshark software:MN503 Overview of Internetworking P a g e | 2 of 53) Does reliable transfer of data imply no errors in data transmission? Justify your answer.4) Can the Wireshark protocol analyser be used to generate packets for different protocoltypes? Justify your answer.5) List the different purposes for which a protocol analyser such as a Wireshark can beused.PART 1 – UDP ProtocolUse an application that generates UDP packets. Run Wireshark and capture packets foraround 1-2 min. Stop Wireshark and use UDP in the filter bar to list only the UDP packets.Whenever possible, when answering a question below, you should place a screenshot of thepacket within the trace that you used to answer the question asked. Annotate thescreenshot to explain your answer.1) What application have you used to generate the UDP packets? Select one UDP packetfrom your trace. From this packet, determine how many fields there are in the UDPheader. Name these fields.2) From the capture determine the data rate of the UDP packets? Explain what you need todo in Wireshark to obtain this automatically?3) The value in the Length field is the length of what? Verify your claim with your capturedUDP packet.4) What field in the UDP packet identifies the application in the end host?5) Is the purpose of checksum field in a UDP packet to offer reliability? Justify your answer.6) Would you use UDP for the reliable transportation of real-time or non-real time traffic?Justify your answer.PART 2 – TCPGenerate TCP packets by using a suitable application. Capture the generated TCP packets byusing Wireshark. Answer the following questions.1) What is the purpose of TCP protocol? How does it differ from UDP protocol?2) For a captured TCP packet, what is the IP address and TCP port number used by theclient (source) computer and the destination computer. Annotate this on a screen shot.3) What is the purpose of TCP port number? How it is used?4) Why do ICMP (ping) packets do not have a TCP port number? Justify your answer.MN503 Overview of Internetworking P a g e | 3 of 55) From the TCP capture, what is the sequence number of the TCP SYN segment that isused to initiate the TCP connection between the client computer and the destination?How is TCP SYN segment found? Annotate it on the screen shot.6) From the TCP capture, calculate the Round trip time (RTT) for sending a TCP segment.How is the RTT obtained?Part 3 – DNS Protocol1) Explain briefly what DNS protocol is? What is the IP address of your local DNS server?Provide a screenshot to indicate your answer on it.2) How would you flush your local DNS server? Use a web browser to visit any website andcapture and filter the DNS packets on Wireshark. What are the ports used in the DNSmessage? Provide a screenshot to support your answer.MN503 Overview of Internetworking P a g e | 4 of 5PART B- Riverbed Modeler based Simulation ExperimentsDataTech Consulting wants you to create a 10base-T hub star based Ethernet in theRiverbed Modeler using Rapid Configuration. You can use Ethernet_wkstn as the peripherynode model i.e. as the hosts/Ethernet stations, and 10base T link model to connect hosts tothe hub. Use interarrival time between packets to be exponentially distributed with a meanof 0.03 sec. First have 10 ethernet node stations connected to it.Evaluate the performance of the 10base-T Ethernet in terms of throughput vs delay forpacket sizes of constant distribution for each of the following two packet sizes: 512 bytes,and 1500 bytes. Make sure you apply the same traffic distribution to each of thehosts/Ethernet stations. Then repeat the same for 20, 30, 40, 50, 60, and 70 stations.Use graphs wherever required in the questions below:(i) In your opinion what is the purpose of network simulation? What are the differentsimulation tools available (max up to 4) and state their advantages and disadvantages.(ii) Capture the graph of throughput vs delay for one of the two packet sizes andexplain the nature (shape) of the throughput vs delay graph as the load on theEthernet is increased. What is the load in this case? Put the final graph in the report.(iii) From the graph of throughput vs delay for 1500 bytes packet size and stationsranging from 10 up to 70 in increments of 10 how would you determine the optimalnumber of Ethernet stations that could be supported on the 10base T Ethernet hub? Putthe final graph in the report.(iv) What is the nature of the data traffic generated in the above Ethernet network.Justify your answer.(v) What are the sources of the delay in the throughput vs delay graph? State and brieflyexplain each of them.