讲解 FIT1047 Introduction to computer systems, networks and security – S1 2024 Assignment 3 – Networks

FIT1047 Introduction to computer systems, networks and security – S1 2024

Assignment 3 – Networks

INSTRUCTIONS

This assignment has THREE parts. Make sure you read the instructions carefully.

Part 1: WLAN Network Design and Security (25 marks)

For this part of the assignment, you will perform. a real-world WLAN site survey. Your task is to produce a map of part of a building that gives an overview of the wireless networks that are available, as well as an analysis of the network.

What you will need: a WiFi-enabled laptop (some smartphones also work, see below), and a place to scan. You have to perform a survey of parts of the Monash Clayton / Malaysian campus.

You have to complete two tasks (a survey and a report).

Task 1.1: Survey (9 marks)

For Australian campus cohort:

Create a map and survey of (a part of) the following building on our Clayton Campus:

● Students with student number ending with “0”: Woodside Building

● Students with student number ending with “1”: Hargrave Andrew Library

● Students with student number ending with “2”: Sir Louis Matheson Library

● Students with student number ending with “3”: Learning and Teaching Building

● Students with student number ending with “4”: Menzies Building

● Students with student number ending with “5”: David Derham Law Building

● Students with student number ending with “6”: Learning Village

● Students with student number ending with “7”: Green Chemical Futures

● Students with student number ending with “8”: Mathematics & EAE

● Students with student number ending with “9”: Campus Centre

(You can find the location of the building here - Choosing Clayton campus)

For Malaysian campus cohort:

Create a map 1 and survey of (a part of) any building of your own choice on our Malaysian Campus.

(You can find the location of the building here - Choosing Kuala Lumpur campus)

A simple floor plan will be sufficient, it does not have to be perfectly to scale. See the appendix for an example. The map should be labelled with all relevant information (e.g.  dimensions, doors, walls and material such as wood or concrete or glass, if used for the discussion). Your survey should cover an area of at least 60 square metres (e.g. 6x10 metres, or 4x15, or two storeys of 6x5 each). Be sure to take the analysis in Task 1.2 into account, by designing your survey to include walls, doors etc. it will be easier to write something interesting in Task 1.2.

Furthermore, your survey must include at least three WiFi access points. If you want, you can create an additional AP with your phone (using “ Personal hotspot” or “Tethering” features).

For the survey, use a WLAN sniffing tool (see below) in at least eight different locations on your map. For each location, record the technical characteristics of all visible APs.

Depending on the scanning tool you use, you record features such as the network name, MAC address, signal strength, signal to noise ratio (SNR), 802.11 version(s) supported,   band (2.4 or 5 GHz) and channel(s) used.

Add the gathered data from the survey into the map of the covered area. On the map you   indicate the location of the access points and the locations where you took measurements. For the access points, use the actual location if you know it, or an approximation based on the observed signal strength (e.g. if you don’t know exactly where it is).

For each measurement point, you either add the characteristics directly into the map, or create a separate table with the details. You can submit several maps if you choose to enter data directly into the maps, or a single map if you use additional tables. Create the map yourself, do not use the mapping features available in some commercial (i.e., paid) WLAN sniffing tools.

Task 1.2: Report (16 marks)

Write a report (word limit 600) on your observations analysing the data collected in the previous step (Task 1.1). Your analysis should investigate the following aspects:

●   Channel occupancy: Are different access points competing on the same channels? Are they configured to use overlapping channels? Could the configuration be improved?  (4 marks)

●   Attenuation from walls, doors etc.: How do different materials affect signal strength

and/or noise? Can you notice a difference in attenuation for different APs? (4 marks)

●   Coverage: Do the access points sufficiently cover the desired area? Could the

placement or configuration be improved?  (4 marks)

●   Any other aspect of your own choice. Here are a few suggestions to pick one or more:

○    measure the attenuation caused by your own body

○   determine the overlap that has been implemented to enable roaming

○   describe how you interpolated the locations of access points from the signal strengths

○    measure how interference affects download speeds

Describe your findings and explain them with some technical detail (i.e., not only say what you found, but also how you performed the analysis or why you think the

network is behaving that way).

(4 marks)

Tools: You can use e.g. Acrylic Wifi (https://www.acrylicwifi.com/en/) for Windows, NetSpot  (http://www.netspotapp.com) for macOS and Windows, and LinSSID or wavemon for Linux. If you have an Android smartphone, apps like Wifi Analyzer can also be used. On iOS, WiFi scanning apps do not provide enough detail, so iPhones won’t be suitable for this task.

For drawing the site maps, any drawing tool should work, for example LucidChart, or even presentation tools such as PowerPoint, Keynote or Google Slides. Scans of hand-drawn    maps are NOT acceptable.

Submit your work for this part (Part 1) as a PDF file (independent of Part 2) in Moodle.

Part 2: Reflections (hurdle requirement, no marks)

Copy/paste your reflections for weeks 7 to week 10 (4 weeks in total) from the Ed Lessons    into a PDF document. This part is a hurdle requirement, i.e., we won’t mark the other parts if you do not submit this part. The reflections can be just a few sentences per week, but need   to genuinely relate to your learnings for the week.

Submit your reflection for this part (Part 2) as a PDF file (independent of Part 1) in Moodle.

Part 3: Internet Traffic Analysis and basic network knowledge (25 marks)

This part of the assignment must be done in-person during your week 12 allocated Applied Session. You will be given 1.5 hours to complete this part. You cannot start this part elsewhere or in another time slot. Bring your student ID and own device (recommended with your charger, in case the device is running out of battery during your quiz)!

This part of the assignment requires you to download a PCAP file, open it in Wireshark and answer a few questions about the captured frames. The PCAP files are individualised, so make sure that you download the correct file while you are logged into Moodle. In addition,  you will need to answer some multiple choice questions on basic network and security topics.

You can access your individual PCAP file through the Assignment 3 Part B quiz link on Moodle at your Week 12 applied session. All of your answers have to be submitted via that Moodle quiz. You have 1.5 hours to complete the quiz  during your allocated

Applied Session in Week 12 (in-person)  . You must not communicate with other people via any kind of media (e.g. phone, email, social media, communication tools such as whatsapp, WeChat etc.) during any time when you are doing this part of your assignment.

A sample quiz will be available on Moodle from week 10.

Here are a few tips on how to approach these tasks.

MAC addresses:

These are the addresses of individual devices at the Data Link Layer. Each frame contains a sender and receiver MAC address. For each frame, think about which device would be the sender and which the receiver.

IP addresses:

These are the Network Layer addresses. Remember that we use the DNS protocol to map a human-readable address (such as www.monash.edu) to an IP address (such as 202.9.95.188). So in order to find out the IP address for some of the devices, you may have to try to find DNS requests and responses in the PCAP file.

TCP connections:

Remember that each TCP connection starts with a three-way handshake. This was covered in the lectures, so you may have to go back to the videos if you’re not sure what those frames look like.

Appendix: Sample map showing APs and survey location details