COIT20229 Networking with TCP/IP (Term 3, 2014)
Assessment item 1—Written Assessment
Due date: 11:00pm AEST, Friday, Week 10 ASSESSMENT
Weighting: 40% 1
This assessment item relates to the course learning outcomes 1 to 7 as stated on page 3 of the course profile.
Please write your answers to all questions in the ‘Template for Your Answers’ Section of this document and upload only that template. Please show all your working and steps. Please ensure that you write your answers in your own words to avoid possible plagiarism and copyright violation. You can understand the Plagiarism Procedures by following the corresponding link in the CQUniversity Policies section of the Course Profile.
DO NOT copy the assignment questions with your answers, unless required. Not copying the assignment questions will reduce the similarity level on Moodle.
Question 1 (1.5+1.5=3 marks)
With respect to TCP/IP;
a) Describe what physical, logical and port addresses are and why they are required.
b) Provide a real example of a physical, logical and port address - this should be from your own computer on your own network, or a lab computer or a work computer – include details of how you obtained each of the addresses and include a screen shot displaying each address – for the port address identify the application or program that is using it.
Question 2 (1+1=2 marks)
An organisation has been granted a block of addresses starting with the address 220.127.116.11/22.
a) Create 3 subnets for this organisation with the first subblock of 250 addresses, the second subblock of 60 addresses and the third subblock of 12 addresses. for each correct answer)
b) How many addresses are left?
Question 3 (1+1+1=3 marks)
a) Provide two reasons why you think dynamically assigning IP addresses are useful? (1 mark)
b) Is the IP address 192.168.12.254 a valid address for use by a computer connected directly to the Internet? Explain your answer. (1 mark)
c) Is it possible to divide a class C network into 14 subnets with 15 computers connected to each sub network? Explain your answer. (1 mark)
Question 4: (1+1+1+1=4 marks)
A sending application has sent 1240 bytes to a receiving application using TCP. The congestion window (cwnd) is set at 200 bytes (assume it does not change for the duration). The receiving application has sent an acknowledgement number of 1180 with a receiver window (rwnd) of 120 bytes.
a) Draw a diagram showing the sliding window and next byte pointer similar to the example provided below based on the details given above.
b) The sending application then receives a further acknowledgment of byte 1220 with an rwnd of 100 bytes. Draw a diagram representing the new sliding window and next byte pointer.
c) The sending application then sends a further 80 bytes to the receiving application, which responds soon after with an acknowledgement of byte 1300 with an rwnd of 80 bytes. Draw a diagram representing the new sliding window and next byte pointer.
d) What is the maximum amount of data the sending application can send at this time?
An example of the layout required, showing sliding window and next byte pointer (the light blue section represents the sliding window):
Following table is an example only to complete your answers.
1161-1180 1181-1200 1201-1220 1221-1240 1241-1260 1261-1280 1281-1300 1301-1320 1321-1340 1341-1360
Question 5 (1/2 x 6 = 3 Marks)
a) Change the following IP addresses from dotted-decimal notation to binary notation:
b) Change the following IP addresses from dotted-decimal notation to hexadecimal notation:
c) Change the following IP addresses from hexadecimal notation to dotted-decimal notation:
d) Change the following IP addresses from binary notation to dotted-decimal notation:
00101110 01100101 01010111 10101010
10000010 00111010 10101010 01001101
e) Find the class of the following IP addresses:
f) Find the netid and hostid of the following classful IP addresses:
Question 6 (1+1=2 Marks)
Given the following IPv6 addresses in hexadecimal colon notation, answer the following questions. Where applicable leave your answers in fully expanded hexadecimal colon notation.
(a) What is the full (expanded) address of the abbreviated IPv6 address FDEC::CF:0:FFFF (1 mark)
(b) What is the type of block of the abbreviated IPv6 address
2001:A100:FC1::A4B8:AE12:3217:FCBA (1 mark)
Question 7 (6 marks)
Use Wireshark tool to capture packets when you download Lecture 1 from the COIT20229 Course Webpage. Before you undertake this task, you should have Wireshark installed in your home computer/notebook and connected to the Internet. It is advisable that you have attempted the packet capture exercises using Wireshark that are scheduled for Weeks 7-9. This task cannot be completed in any CQUniversity lab.
a) Submit the captured pcap file. You should filter the file so that only TCP traffic is included. (1 mark)
b) What is the server IP address? (0.5 marks)
c) What is the application layer protocol involved? (0.5 marks)
d) What is the client port number for data download? (0.5 marks)
e) What is the server port number for data download? (0.5 marks)
f) How many data bytes have been downloaded? (0.5 marks)
g) What is the size of the downloaded Lecture 1 file? (0.5marks)
h) Discuss the difference in your answers to parts f) and g). You need to consider the packets formats in your discussion. (2 marks)
Question 8 (2+2+2=6 marks)
From the following network topology diagram, develop the router table for each of the routers (R1, R2 and R3). Note that R2 is actually a Firewall/Gateway, but still acts as a router and requires a routing table.
Question 9 (11 marks)
To answer this question you are asked to take on the role of a newly employed Systems Administrator for a medium sized business. One of your duties is to administer all of the Local Area Networks (LANs). Upon initial investigation you discover that the network is using fixed IP addresses for all of the connected hardware. A considerable amount of your time is taken up with assigning and configuring IP addresses for visiting staff and staff that tend to move around the company frequently. This is obviously a poor use of your time. You decide that by implementing DHCP across all of the LANs you can save yourself considerable work which in turn can save the company money over a period of time.
Upon suggesting this to the manager you have been asked to make your case in writing. This should be in the form of a report which includes the following:
• a description of IP addressing in general,
• what DHCP is,
• how DHCP works,
• why DHCP would be beneficial to the organisation, and
• Highlight the monetary and organisational benefits by comparing the two addressing methods (static and dynamic).
The manager is not an IT expert so the report should be written in such a way that the details can be easily understood by a person with minimal IT background.
The report should be approximately 1,500 words (minimum 1,000, maximum 3,000); you can include diagrams if you find it helps describe how DHCP works.
The report will be marked on the basis of correctness, completeness, relevance, and level, i.e. aimed at someone with minimal IT background.