DATS2410/ITPE2410 Networking and Cloud computing Obligatory assignment 2 - Individual task This is the second among the three obligatory assignments, which will carry 40% of your final grade. You must do this individually and submit according to the given instructions. All the answers must be your own and any form of copying is not acceptable. If you use anything from the other sources (e.g. book, articles, blogs, …), give proper citation and references to them. 1. An organization wants to build a computer network and plan to have separate LANs for each of its three departments A, B, and C, and connect them together and to the Internet. A network engineer proposed a network design as given below: The organization has a maximum capacity of x, y, and z number of hosts in the departments A, B, and C respectively, where x = first 2 numbers in your student number y = the next 3 numbers from the student number, and z = (the remaining number + 2)*x. For example, if your student number is s237850, then x = 23, y = 785, z = (0+2)*23 = 46.You are given a role for setting up and configuring the network. a. Assign IP addresses in the network, first using FLSM (fixed length subnet mask) and then using VLSM (variable length subnet mask). In each case and for each subnet, explain how many IPs required, what IP do you assign to which host/interface in the network, what is network id, broadcast IP, minimum IP, maximum IP, and possible number of hosts. In your implementation, use a contiguous block of any appropriate private IP addresses. Based on the resulting IP assignments with FLSM and VLSM, can you explain which addressing method is the best one? If you were to use public IPs, what IP block size you need to buy in those two cases. b. What is longest prefix matching in the context of routing in a network? Provide the routing/forwarding tables for each of the three routers based on longest prefix matching so that each host can communicate with all other hosts and connect to the Internet. Explain how the tables are created and how the packet is forwarded when Ax sends a packet to Cz. 2. Based on your answers above in 1) with VLSM, implement the network in Cisco packet tracer using two different routing methods: a. static routing, and b. dynamic routing using RIP. Both the implementations should work as expected, i.e. each host can communicate with all other hosts and there is a possibility to connect to the Internet. You don’t need to include all the hosts; you can have just 2-3 hosts in each department/LAN. You should label the components in the network properly with host names, router names, IPs… Save the two implementations as Oblig2-PT-static.pkt and Oblig2-PT-dynamic.pkt. Explain briefly how did you setup the static routing and dynamic RIP routing and your understanding on the differences between the two. 3. Internet access is provided by subscribing a dedicated Internet connection from a local internet service provider (ISP) through the router R3, which supports NAT. Explain with diagram(s), NAT table, and IP addresses you assigned, how NAT works when the host Ax browse the HiOA website (www.hioa.no). Suppose that the R3 router interface received a dynamic IP 158.109.95.150 from the ISP. You can assume appropriate port numbers, as you like. 4. When a data packet from host Ax is sent to host By in the network you configured above in 1), enumerate the steps taken for resolving the addresses in data-link layer when a. all ARP tables are initially empty. b. ARP table is up-to-date. In your explanation, use MAC addresses of the nodes from your Packet tracer implementation in 2). If host Ax wants to send IP datagram to host A1, will Ax ask router R1 to help forward the datagram? Why? In the Ethernet frame containing the IP datagram, what will be the source and destination IP and MAC addresses? 5. Use Wireshark to capture packets transferred when you visit the web page http://128.39.121.133/oblig2.php from your local machine (laptop or desktop), and then enter and submit your address (a valid unique address is expected). Save the captured file as Oblig2-Wireshark.pcapng. Based on the captured packets [consider the last two packets only: POST /oblig-2-reps.php and its response], answer the following questions. You should provide supporting screenshots with places from where you got the answer MARKED. a. What type of HTTP connection it used: persistent or non-persistent? b. How many bytes of data returned from the server to your web browser? c. What type of transport protocol is used? d. What IP addressing did it use, IPv4 or IPv6? e. What is the source and destination port addresses used in the request and response packets? f. What is the size of the user data (payload) in the case of sending (HTTP request) and receiving (HTTP response) packets? g. What is the overhead (size) taken by the HTTP, TCP, IP and Ethernet headers in addition to the user data in case of the response packet? h. How many TCP segments used by the request and the response data? i. Why don't you see Preamble and CRC in the Wireshark captured Ethernet frame? j. Recall HTTP, TCP segment, IP datagram, and Ethernet frame formats/structure from the lecture slides:Identify all the fields in those formats/structures in the captured Wireshark packets and fill them up for the response (receiving) packet. Show format diagrams filled with the values of all the fields.6. Self-evaluation: Evaluate your own submission by filling up the table below. It has two parts: expected marks (out of the given full marks in brackets), and comments (categorywise). Give comments as lists of short statements mentioning positive aspects, issues/weaknesses, and any other comments worth mentioning. Category (Full marks) Expected marks Comments 1.a. IP addressing (20) 1.b. Longest prefix (10) 2.a. PT (static) (12) 2.b. PT (RIP) (12) 3. NAT (12) 4. ARP (12) 5. Wire-shark (15) Report & submission quality (5) Own evaluation (2) Total (100) Hand-in: • A report file named Oblig2-Report.pdf, containing all the questions and answers, selfevaluation of your submission. The report is supposed to be as complete as possible with questions, answers, diagrams, screenshots, and references. • Packet tracer files for all your Cisco packet tracer implementations: Oblig2-PT-static.pkt and Oblig2-PT-dynamic.pkt. • Wireshark capture file: Oblig2-Wireshark.pcapng. • Other files, if any. • Place your all submission files in a directory/folder named as Oblig2-yourstudentnumber. Compress/zip this directory into a single file named Oblig2-yourstudentnumber.zip (use ZIP compression, not any other compression such as RAR…) and submit this file in the hand-in folder Oblig2-Individual inside Hand-ins in Fronter. • Important notes: o Submit on time to avoid last minute technical problems. o Duplicate submission will not be considered. Therefore, make sure everything is included and correct before submission. o Explanation details, supporting documents (such as figure, screenshots etc.), completeness, clearness, correctness and preciseness of the answers, writing, and structure of the report are in general taken into account in the evaluation. o Not following the instructions explicitly stated will lead to deduction in your score. o If the given info is not enough and you need to assume something, do mention that clearly. o If there is anything not clear or wondering about, do ask the course teacher ON TIME. All the best!