This assignment is designed to help you develop skills and strengthen your understanding of data communications. Answer the questions as if they are a professional presentation to a client. Thus justify what you say in terms of what will work well for the client. Your submission should be around 5 to 10 pages, but be succinct. Your assignment will be submitted electronically as below with TurnItIn on the COMP247 iLearn page. Question 1 (22 marks) – Transport Layer a) As we have seen, the Internet layer of TCP/IP has two protocols – IPv4 and IPv6. The transport layer provides two main protocols TCP and UDP (along with some special-purpose, minor protocols). But these are for very different reasons. Why are the Internet and Transport layers very different in providing two protocols? (8 marks) b) Since UDP does very little that is different from IP, why do we even have a transport layer such as UDP? (7 marks) c) Describe how DDoS attacks may be mounted against TCP and UDP services. In what way will being connection oriented be different for TCP and UDP? (7 marks) Question 2 (22 marks) – IP Addressing a) Perform the following boolean operations on the given bit patterns (3 marks) i. not 11100010 ii. 11100010 or 00001110 iii. 11100010 and 00001110 b) What are the subnet masks for the following slash address blocks? (3 marks) i. /9 ii. /17 iii. /31 c) Are the following address masks legal? If so, what are their slash forms? If not, why are they not legal? (4 marks) i. 255.255.248.0 ii. 255.224.252.0 iii. 255.255.255.224 iv. 255.255.156.0 d) How many computers are in networks with the following address blocks? (2 marks) i. /13 ii. /26 e) A small company is assigned the class C network 188.8.131.52. You need to divide this network to provide subnets for three departments using fixed-length subnetting. The departments are approximately the same size. Show the network and broadcast addresses for each subnet. Show the slash notation. How many hosts are on each subnet? Are the resulting subnets class C networks? (10 marks) Question 3 (20 marks) – Wireless a) Explain why CSMA/CD scheme used in traditional Ethernet LANs cannot be used in 802.11 wireless LANs. (5 marks) b) A supermarket uses WiFi to enable staff to check inventory levels and to perform price checks. Staff have complained that the wireless scanners they use to check stock levels do not work reliably in some isles. The supermarket manager has contracted you to diagnose the wireless problems and correct them. The supermarket is 60m by 40m. Assume that the useful range of WiFi within the warehouse will be 15m radius. The access points are organised into a grid with the following channel allocations: i. You have determined that the channel allocations are not optimal, how would you improve upon the current channel allocations? (10 marks) ii. As you are reconfiguring the access points you notice that none of them currently have any security enabled. Is this a problem, and if so, what type of security would you recommend? (5 marks) Ch1 Ch6 Ch1 Ch6 Ch1 Ch6 Assessment For all questions in this assignment not only content but also presentation will affect your mark. You will lose marks if there are problems with the presentation, particularly with clarity. This means that your answers to each question should be a coherent statement and that the spelling and grammar of your submission will be taken into account in assessing its presentation. For full marks, your answers should all be correct, clear, and coherent. The standards of marking described in the unit outline L.O. 1 will be applied to this assignment as relevant to the assignment topics. In addition, the following particular standards will be applied in marking this assignment: • Spelling and grammar: o Assignment submissions with more than 4 spelling or grammatical errors will not achieve a grade higher than distinction; submissions with more than 8 such errors will not achieve a grade higher than credit. • Clarity: o Ambiguous or poorly worded answers will receive a grade no more than a pass for the individual question. o Minor issues of clarity will receive a grade no more than credit for the individual question. • Correctness of approach taken and answer obtained: o Incorrect answers with the correct logic or approach will receive no more than a pass for the individual question. o Correct answers with incorrect logic or approach will receive no more than pass for the individual question. o Incorrect answers with no explanation of the approach taken or with the incorrect approach will receive a fail grade for the individual question. The questions will be marked individually, the marks totalled, and a final grade assigned that is no more than indicated by the total marks, and no more than allowed by the standards specified above and in the unit outline.