Demonstration Of Routing Concepts – Assignment Questions

Instructions

This assessment task requires you to demonstrate your knowledge of routing concepts by completing a number of exercise questions. The questions are designed to help you to achieve the unit learning outcomes as listed in the unit profile.

Instructions

You must do this assignment on your own – it is not a group assignment.These questions will require more time and effort than the first assignment so plan ahead and start as early as possible.  Question #3 may require additional research and analysis to complete.

Type all your answers in the ‘Template for Your Answers’ Section of this document and upload only that template.  You can do that by copying the Template section into a new Word document for uploading.  Answers that are not typed into the “Template for Your Answers” section may not be marked, or may be returned to you for re-typing and re-submission – late penalties will apply.

Where instructed, you must show the steps you took to arrive at your answers. Write your answers in your own words to avoid potential plagiarism and copyright violations.

You must submit the Answer section as a Word file (.doc or .docx).  Do not submit PDF’s or any other type of file without express permission from the Unit Coordinator.Plagiarism Procedures can be found in the CQUniversity Policies section of the Unit Profile. 

Assessment Requirements and Marking Criteria

There are 3 main questions each with sub-questions and the requirements are stated for each one.  You must answer all questions and their sub-questions.   Marks are indicated in the Answer Template.The questions will be marked on correctness, logic and clarity, and addressing all parts of the question.  

The Assignment Questions begin on the next page. 

REMEMBER, USE THE ANSWER TEMPLATE FOR ALL YOUR ANSWERS 

Question 1  – Routing                                                                           

Given the following network diagram, assume that all the networks shown are aware of each other and have fully updated routing tables.  Answer the questions that follow.  The questions (1 mark each except q.8):

1. From the point of view of router R4, what is the next-hop address for a packet addressed to host 161.22.0.15/18?
2. From the point of view of router R1, which of its interfaces would it choose for a packet being sent to network 161.22.0.0/18?
3. A host with an IP address of 200.11.60.36/24 has just sent a packet to a host with address 150.32.0.240/18. How many hops is required between source and destination?
4. A packet originating from network 220.10.40.0/24 arrives at router R1, however, R1 determines that the destination network is not in its routing table. What does R1 do with the packet?  
5. A packet arrives at router R2 with a destination address of 140.21.0.10/22. Which interface port does R2 forward the packet out of?
6. A packet at router R3 has a destination address of 220.10.40.5/26. What next-hop address would R3 use for this packet?  
7. A packet is waiting at router R4 for forwarding. If the next-hop was a “direct delivery”, which of these three networks is the destination network?  3.0.0/16, or 150.32.0.0/18, or 220.10.40.0/24?
8. Complete the information in the routing table for router R2 as shown in the Answer Template for networks 150.3.0.0/16, 150.32.0.0/18, and the Default network. Show the masks in longest mask order using CIDR format .

Question 2 – Fragmentation in IPv4                                                                

An IP datagram 5,400 bytes long with no options arrives at a router, which determines that the next destination has an MTU of 1,500 bytes.  Use the Answer Template to complete the following questions, showing your calculations and reasoning. 

1. Assuming that the router decides to fragment the packet into 4 fragments, determine a correct size for each fragment, and identify the starting byte and ending byte of each fragment (2.5 marks).
2. Calculate the fragmentation offset for each fragment (1.5 marks).
3. State whether the total number of bytes from all 4 fragments leaving the router will be greater than the initial datagram size that arrived, or less than the initial datagram size, and the reason (1 mark).

Question 3 – Congestion controls in TCP                                                

This question affords you the opportunity to extend your thinking about congestion controls in TCP beyond the textbook to observe what a real-world technology company, Google, is doing in this space. 

First, read this Network World article that reports on Google’s approach to improving congestion controls in TCP:You should also read the following more technical paper about it: After reading both articles, answer the following questions:

1. Write a brief summary of the congestion controls currently available in TCP as covered in this Unit (1 mark)
2. Identify and explain two problems with current congestion controls in TCP that are pointed out in the articles (2 marks)
3. Summarize in your own words the difference(s) between the current TCP congestion controls and Google’s new BBR protocol (3 marks)
4. The Network World article points out that it is difficult to get a new protocol accepted as a global standard for TCP/IP. Why do you think this is the case?   Give carefully thought out reasons for your answer.  (4 marks)

Important:  for every direct quotation you use from these two sources or any other source, you must immediately, after the quote, provide your own explanation of the quotation (for example, explain why are you quoting it, how does it help answer the question, how does it support what you are saying?) – marks will be deducted for failure to do so.  In addition, correct referencing conventions must be used throughout your work using the Harvard referencing convention.  Your answers will be marked on clarity, logic, relevance, use of own words and fully addressing all parts of each question.

Remember that quotations alone will not be accepted as your explanation of the questions.  Quotations can support your explanations, but you must still provide the explanations yourself.   Best way forward is to keep direct quotations to a minimum, and use your own words. 

TEMPLATE FOR YOUR ANSWERS

Type your answers in this section in the spaces provided.  Spaces can expand as you type. 

First Name:_________________________  Last Name:____________________________

Student ID: __________________________ 

Question Number	Mark allocated	Marks earned
1. 2. 3. 4. 5. 6. 7. 8.	150.3.0.3 M2 1 First router R1 will try to find the longest match. If it not found then the packet will be dropped. M0 150.3.0.3 150.3.00/16   q.8 Routing table of router R2:    Prefix Network address Next-hop address Interface 255.255.0.0 150.3.0.0 150.3.0.2 loopback 255.255.255.0 220.10.40.0 150.3.0.3 M0 255.255.192.0 161.22.0.0 150.3.0.3 M0 255.255.192.0 150.32.0.0 150.3.0.1 M0 255.255.255.0 200.11.60.0 200.21.60.1 M1 255.255.252.0 140.21.0.0 140.21.0.1 M2	1-7 1 mark each, q.8 3 marks
a)	5600-20 = 5580 1st Fragment  size  1480 bytes Offset = 0 Byte range : 0 – 1479 2nd fragment size 1480 bytes Offset = 1480  Byte range = 1480 – 2959 3rd fragment size 1480 Offset = 2960 Byte range ; 2960 – 4439 4th fragment size 1140 (= 5580-1480-1480-1480) Offset = 4440 Byte range : 4440 – 5580	2.5
b)	Segment 1 offset  = 0 Segment 2 offset = 1480 Segment 3 offset = 2960 Segment 4 offset = 4440	1.5
c)	The 4 fragment size is grater then the initial datagram size because the MTU is 1500 and the actual size is 1480. Their fore every fragment size is 1480. Therefore, the total 4 fragment size is grater then the initial datagram size.	1
1.	Network congestion is occurring when a sender sends lots of packets to the sender which may cause of congestion in network. TCP has a feature of congestion control. TCP control the packet flow.  TCP congestion control mechanism ensure that the sender does not overflow the network.	1
2.	TCP slow down the network when it identified the data loss. It is a big problem. Because, this process is too slow and network already many packets.	2
3.	BBR is a congestion control algorithm that is agnostic to transport-layer and link-layer technologies, requires only sender-side changes, and does not require changes in the network. But TCP operate its congestion control system in network level. Its slow down the network when packet loss is detected.	3
4.	It is default to get a new protocol accepted as a global slandered for TCP/IP. Because 90% of the internet is used TCP as congestion control system. Internet Engineering Task Force (IETF) calculate that more than 90% of internet traffic is transmitted via TCP.	4
Total marks awarded	25 (max)
Less late penalties if applicable
Less plagiarism penalties if applicable