networking
SIT202 Computer Networks Trimester 2, 2020 Problem Based Learning Task 2 Due Date: 8pm Sunday September 27th, 2020 This assessment is marked out of 100 marks and is worth 35% of your final unit mark. This assessment task must be completed individually, group work and/or collaboration with other students is prohibited. All work completed/submitted as part of this assessment task must be your own, individual work. Any content drawn from other materials, including unit materials, must be clearly quoted where appropriate, and/or clearly referenced. All students should review and be familiar with the content provided by the University regarding how to reference other materials: https://www.deakin.edu.au/students/studying/study-support/referencing And in particular the information provided regarding Academy Integrity: https://www.deakin.edu.au/students/studying/academic-integrity Use of Illustrations Note that several questions below may require you to include an illustration in your answer. This must be your own illustration, not a graphic copied from the Internet or any other source (textbook, class slides, etc.). Illustrations from the Internet (whether directly copied or reproduced by you) will not be awarded any marks. There are many illustration programs that you may use for this purpose, including several free applications accessible via the Web. If you are unable to use these programs however, you may include a scanned/photographed hand-drawn illustration in as long as that illustration is clearly legible. HD Tasks Note that there are one or more “HD Tasks” identified in the requirements below. These tasks are more difficult to answer and total 20% of the marks available for this assessment. A HD result reflects achievement in the unit of a deep understanding of the unit content and ability to extend your knowledge beyond that covered in the unit directly. You can expect these tasks will be assessed harder than other tasks reflecting demonstration of this level of achievement. https://www.deakin.edu.au/students/studying/study-support/referencing https://www.deakin.edu.au/students/studying/academic-integrity Submission Answers must be submitted via the unit site (CloudDeakin) to the TurnItIn-enabled folder for Problem Based Learning Task 2. Answers to each question and sub-question must be clearly identified in your submission. Acceptable file formats include Word documents, PowerPoint documents, PDF documents, text and rich text files, and HTML. Compressed files such as ZIP files or RAR files, or any other format that cannot be processed by TurnItIn cannot accepted and will not be marked. Extensions Applications for an extension can be made before the due date/time via the tool in the unit site (CloudDeakin). The link to the extensions tool can be found by clicking on the Assessments menu at the top of the screen and selecting the Extension Request link. Extension applications must clearly explain unusual circumstances that have impacted your studies and must contain enough information for the duration of any extension to be determined. Students applying on the basis of a LAP must at a minimum indicate they are supported by a LAP and indicate that the request for an extension is linked to the disability. Applications for special consideration can be made at any time including (for a limited time) after the due date/time. Information on applying special consideration can be found here: https://www.deakin.edu.au/students/studying/assessment-and-results/special-consideration Note: Applying for an extension or special consideration does not guarantee a positive outcome. You should always continue working on the basis that an extension is not granted, such as submitting any work you have completed by the original due date/time to avoid a late penalty. If an extension is then granted you can resubmit an updated version of your assessment later. https://www.deakin.edu.au/students/studying/assessment-and-results/special-consideration Question 1 / Week 6 (12.5 + 8 = 20.5 marks) Computer networks are constructed using a modular architecture known as layering. a) Identify and describe the five different approaches to configuring IPv6 addresses. In your answer, explain why it may be beneficial to use stateless DHCPv6. b) (HD Task) Consider the following weighted graph: A B D E C2 2 3 4 1 15 Demonstrate the step-by-step calculation of the least-cost tree starting from node A using Dijkstra’s Algorithm and draw a figure illustrating the final least-cost tree. Question 2 / Week 7 (12 + 6 = 18 marks) a) Transport protocols usually provide multiplexing and demultiplexing services. Explain how this works and why it is necessary. b) (HD Task) Sliding-window flow control provides both flow control and error control. The TCP protocol implements a variant of this, where an acknowledgement can be sent for segments received without granting permission for additional segments to be sent. If the underlying IP protocol were modified to provide a reliable service, guaranteeing that all segments sent by TCP arrived at the destination without error, explain why it would still be useful to separate the acknowledgement and the granting of permission. Question 3 / Week 8 ((3 + 7 + 5) + (4 + 2) = 21 marks) a) Select three popular Internet domains, examples of which could include amazon.com, facebook.com, google.com, microsoft.com, reddit.com, or any other popular domains of your choosing. i. Obtain the SOA records for each of your chosen domains and present their data in a table. ii. Briefly explain the meaning of each field. iii. Discuss how the observed different values will impact other DNS servers. b) (HD Task) We have examined the HTTP protocol in this week’s materials. For constrained devices such as IoT devices, alternative protocols such as the Constrained Application Protocol (CoAP) are often used instead. i. Describe the CoAP protocol. ii. Explain why CoAP might be preferred for constrained devices. Question 4 / Week 9 (8 + 12 = 20 marks) a) In Week 9 on Slide 6, a figure is shown illustrating SNMP querying how many UDP datagrams have been received by an agent (the agent could be an individual host or a router). Explain how such simple data can be made useful. b) One of the problems encountered for multimedia is jitter. Explain how a playback buffer solves the problem of jitter and discuss whether a playback buffer is useful for live events such as a video call/conference. Question 5 / Week 10 (8 + (5 + 7.5) = 20.5 marks) a) Digital signatures work by generating and signing a digest of a message. Explain why only a digest is signed and why it isn’t necessary to sign the entire message. b) Consider an organisation that has two sites (offices, branches, etc.), each with a typical connection to the Internet via an ISP (such as an NBN connection like many Australian homes). To secure communication between the two sites, a site-to-site VPN has been established using IPsec ESP in tunnel mode. i. Draw an illustration showing the two sites and their connection to the Internet, the VPN tunnel, packets travelling between the individual sites and public Internet sites, and packets travelling between the sites. ii. Briefly discuss the advantages of this approach and explain the services provided by the VPN. SIT202 2020-2 PBL2 Rubric.xlsx Criteria Marks High Distinction (80‐100) Distinction (70‐79) Credit (60‐69) Pass (50‐59) Fail (0‐49) Identify and describe five different approaches to configuring IPv6 addresses 10 All five approaches correctly indicated with clear explanations. At least four approaches correctly indicated with clear explanations. At least three approaches correctly indicated with clear explanations. At least two approaches correctly indicated with clear explanations. Did not identify and describe five different approaches, or your answer is very poor or mostly incorrect. Explanation of why stateless DHCPv6 is beneficial. 2.5 Clear explanation of why it may be beneficial to use stateless DHCP and the kinds of data that can be provided in addition to the configured IP addressing. There are no significant misunderstandings. Clear explanation of why it may be beneficial to use stateless DHCP and a basic explanation of the kinds of data that can be provided in addition to the configured IP addressing. There are no significant misunderstandings. Adequate explanation of why it may be beneficial to use stateless DHCP. Basic explanation of why it may be beneficial to use stateless DHCP, incomplete but most points covered/correct. Did not explain why it may be beneficial to use stateless DHCP or your explanation is very poor or mostly incorrect. Demonstration of OSPF. 8 Complete demonstration that is correct including final weighted graph output. Initialisation and first three steps demonstrated correctly. Initialisation and first two steps demonstrated correctly. Initialisation and first step demonstrated correctly. Did not explain encapsulation and how it works or your explanation is very poor or mostly incorrect. Question 1a Question 1b (HD Task) Criteria Marks High Distinction (80‐100) Distinction (70‐79) Credit (60‐69) Pass (50‐59) Fail (0‐49) Explanation of how transport protocols provide multiplexing and demultiplexing. 8 Clear explanation of how transport protocols provide multiplexing and demultiplexing, and how ports are used as part of this mechanism. There are no significant misunderstandings. Clear explanation of how transport protocols provide multiplexing and demultiplexing, and a basic explanation of how ports are used as part of this mechanism. There are no significant misunderstandings. Adequate explanation of how transport protocols provide multiplexing and demultiplexing. Basic explanation how transport protocols provide multiplexing and demultiplexing, incomplete but most points covered/correct. Did not explain how transport protocols provide multiplexing and demultiplexing, or your explanation is very poor or mostly incorrect. Explanation of why multiplexing and demultiplexing is necessary. 4 Clear explanation of why transport protocols provide multiplexing and demultiplexing and how this contributes to efficient use of the network. There are no significant misunderstandings. Clear explanation of why multiplexing and demultiplexing is necessary and a basic explanation of how this contributes to efficient use of the network. There are no significant misunderstandings. Adequate explanation of why multiplexing and demultiplexing is necessary. Basic explain why multiplexing and demultiplexing is necessary, incomplete but most points covered/correct. Did not explain why multiplexing and demultiplexing is necessary, or your explanation is very poor or mostly incorrect. Explain why separating acknowledgement and granting permission for sending additional segments is still useful given a reliable network service. 6 Clear explanation of why separating acknowledgement and granting permission for sending additional segments is still useful given a reliable network service. Clear explanation of why separating acknowledgement and granting permission for sending additional segments is desirable and a basic explanation of why this is still useful given a reliable network service. There are no significant misunderstandings. Adequate explanation of why separating acknowledgement and granting permission for sending additional segments is desirable and demonstrates understanding of the relationship with an unreliable network service. Basic understanding of why separating acknowledgement and granting permission for sending additional segments is desirable. Did not explain why separating the acknowledgement and permission for sending segments is useful given a reliable network service, or your explanation is very poor or mostly incorrect. Question 2a Question 2b (HD Task) Criteria Marks High Distinction (80‐100) Distinction (70‐79) Credit (60‐69) Pass (50‐59) Fail (0‐49) i‐ Obtain SOA records for popular domains and present in a table. 3 Three SOA records obtained and reproduced in a table that is clear and allows their values to be compared easily. Obtained and reproduced three SOA records and presented them a table poorly. Obtained and reproduced three SOA records. Obtained and reproduced at least one SOA record. Failed to obtain the required SOA records. ii‐ Briefly explain the meaning of each field. 7 All fields indicated with clear explanations. At least five fields indicated with clear explanations. At least four fields indicated with clear explanations. At least three fields indicated with clear explanations. No fields explained or explanations are very poor or mostly incorrect. iii‐ Discuss how different values impact other DNS servers. 5 Clear discussion of the relationship between these values and the behaviour of other DNS servers and how the observed values result in different outcomes. There are no significant misunderstandings. Clear discussion of the relationship between these values and the behaviour of other DNS servers and a basic discussion of how the observed values result in different outcomes. There are no significant misunderstandings. Adequate discussion of the relationship between these values and the behaviour of other DNS servers. A basic discussion of the relationship between these values and the behaviour of other DNS servers but the discussion is very poor. Did not discuss how changes in the SOA field values impacts other DNS servers. i‐ Describe the CoAP protocol. 4 Clear description of the CoAP protocol and its services. There are no significant misunderstandings. Clear description of the CoAP protocol and a basic description its services. There are no significant misunderstandings. Adequate description of the CoAP protocol. A basic description of the CoAP protocol. Did not describe the CoAP protocol or the description is very poor or mostly incorrect. ii‐ Explain why CoAP might be preferred for constrained devices. 2 Clear explanation of why CoAP might be preferred for constrained devices and how this relates to the unique constraints of such devices. There are no significant misunderstandings. Clear explanation of why CoAP might be preferred for constrained devices and a basic explanation of how this relates to the unique constraints of such devices. There are no significant misunderstandings. Adequate explanation of why CoAP might be preferred for constrained devices. Basic explanation of why CoAP might be preferred for constrained devices. Did not explain why CoAP might be preferred for constrained devices. Question 3b (HD Task) Question 3a Criteria Marks High Distinction (80‐100) Distinction (70‐79) Credit (60‐69) Pass (50‐59) Fail (0‐49) Explain how simple SNMP data can be made useful. 8 Clear explanation of how simple SNMP data can be made useful and how the information could be used. There are no significant misunderstandings. Clear explanation of how simple SNMP data can be made useful with a basic explanation of how the information could be used. There are no significant misunderstandings. Adequate explanation of how simple SNMP data can be made useful. A basic explanation of how simple SNMP data can be made useful. Did not explain how simple SNMP data can be made useful. Explain how a playback buffer solves the problem of jitter. 5 Clear explanation of jitter, how a playback buffer resolves this, and how this delays playback. There are no significant misunderstandings. Clear explanation of jitter and how a playback buffer resolves this, and a basic explanation of how this delays playback. There are no significant misunderstandings. Adequate explanation of jitter and how a playback buffer resolves this. A basic explanation of jitter and how a playback buffer resolves this. Did not explain how a playback buffer solves jitter or your explanation is very poor or mostly incorrect. Discuss whether a playback buffer is useful for live events. 7 Clear discussion of whether a playback buffer is useful for live events including the role of any delay. There are no significant misunderstandings. Clear discussion of whether a playback buffer is useful for live events including a basic discussion of the role of any delay. There are no significant misunderstandings. Adequate discussion of whether a playback buffer is useful for live events. A basic discussion of whether a playback buffer is useful for live events. Did not discuss whether playback buffer is useful for live events. Question 4a Question 4b Criteria Marks High Distinction (80‐100) Distinction (70‐79) Credit (60‐69) Pass (50‐59) Fail (0‐49) Explain why only a digest is signed and not the entire message. 8 Clear discussion of why only a digest is signed and why it is not necessary to sign the entire message. There are no significant misunderstandings. Clear discussion of why only a digest is signed and a basic explanation of why it is not necessary to sign the entire message. There are no significant misunderstandings. Adequate explanation of why only a digest is signed. Basic explanation of why only a digest is signed. Did not explain why only a digest is signed, or your explanation is very poor or mostly incorrect. i‐ Illustration showing two sites