Trimester 2, 2016
Problem Solving Report 1
Due Date: 5pm Tuesday August 2nd, 2016
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:
http://www.deakin.edu.au/students/study-support/referencing
And in particular the information provided regarding Academy Integrity:
http://www.deakin.edu.au/students/study-support/referencing/academic-integrity
Unit Learning Outcomes
As per the Unit Guide, the following Unit Learning Outcomes are relevant to this project:
ULO 1. Demonstrate knowledge of concepts and roles of computer architecture and the influence of different layers of communication protocols.
You will be required to demonstrate knowledge of concepts and the architecture of computer networks including protocol layering, and services provided by layers.
ULO 2. Differentiate the types of networks, communication and user oriented protocols, and their influence on transmission speed, reliable delivery and security.
You will be required to demonstrate knowledge of the different types of networks and protocols and how they influence the various characteristics of networks for the transmission of data between devices on a computer network.
Question 1 (8 + 8 + 4 = 20 marks)
Given the following network/s:
Client Switch Router Switch Server
Consider the problem of transferring a large file via the web:
a) Identify how many networks are illustrated and what topologies is/are used in each
network identified. Explain how you identified the networks and topologies in your
answer.
b) For each of the five devices illustrated, indicate which layers of the TCP/IP protocol suite
are certain to be found on that device and briefly explain why.
c) In the Week 1 slides / prescribed reading, it is mentioned that addressing is required at all
layers except the physical layer. If this is true, explain how the physical layer will be able to
deliver/direct the data to its intended destination. Refer to the above scenario/network
when explaining your answer.
Question 2 (6 + 6 + 8 + 12 + 8 = 40 marks)
a) Given that electromagnetic waves can travel at the speed of light, briefly explain how
different signals can arrive at different times when transmitted at the same time. Consider
both wired and wireless media in your answer.
b) Consider a digital signalling approach that uses only two voltage levels to represent binary
data and achieves a data rate of 1Mbps. Explain how increasing the number of voltage
levels could potentially increase the data rate and briefly discuss the potential problems
that may be encountered.
c) A network administrator has identified that several paths throughout the organisation’s
network are experiencing significant latency. Given that latency consists of propagation
time, transmission time, queuing time, and processing delay, discuss how each of these
could potentially be reduced, addressing the identified problem.
d) Consider the Manchester and Differential Manchester encoding schemes.
i. Using the same input of 8 bits, draw an illustration of both schemes. For the input
sequence, you may choose any 8 bits however must include both 1 and 0 bits.
ii. Explain how these schemes achieve self-synchronization.
iii. Explain the relationship between DC components and baseline wandering and how
these schemes resolve this problem.
e) Consider the frequency-division multiplexing and time-division multiplexing techniques.
Give an example where these two techniques could be used at the same time and explain
how they are used.
Question 3
(8 + 12 + 12 + 8 = 40 marks)
a) A colleague is developing a new protocol that will be implemented at the network layer. A key requirement of this new protocol is that data must be delivered in order. There are two data-link technologies to choose from, one is a datagram network and the other is a virtual-circuit network. Identify and discuss two advantages and two disadvantages of each technology.
b) Consider a scenario where a computer is attempting to send data to a device on the same network however the destination is not responding to ARP requests. Identify and briefly explain three reasons why this may occur. Note that the possibilities of the devices being turned off and/or not connected to the network have already been eliminated.
c) Refer to the figure shown on Week 3 Slide 49 for the calculation of CRC codes. Demonstrate the generation of the CRC code using the same approach (same divisor and number of redundant bits) using the 8-bit number 11001101 as input.
d) Consider the following three 16 bit data elements:
1100 1100 1100 1100 0101 1100 0101 1100 0001 0001 0001 0001
Demonstrate the calculation of the 16-bit Internet checksum for this input data.
Marking Scheme
Question 1 (8 + 8 + 4 = 20 marks)
? Part (a)
o (2 marks) Correct identification of number of networks.
o (2 marks) Correct identification of topologies for each network identified.
o (2 marks) Explanation of how networks were identified.
o (2 marks) Explanation of how topologies were identified.
? Part (b)
o (5 marks) Correct identification of layers for each device.
o (3 marks) Explanation of why those layers will be found on that device.
? Part (c)(i)
o (1 mark) Correct explanation of how physical layer will deliver data to destination.
o (3 marks) Explanation of how this applies in the above scenario.
Question 2 (6 + 6 + 8 + 12 + 8 = 40 marks)
? Part (a)
o (3 marks) Explanation of how different signals can arrive at different times.
o (3 marks) Explanation of wired versus wireless media.
? Part (b)
o (3 marks) Explanation of how increasing voltage levels could increase data rate.
o (3 marks) Explanation of potential problems.
? Part (c)
o (2 marks) Discussion of reducing propagation time.
o (2 marks) Discussion of reducing transmission time.
o (2 marks) Discussion of reducing queuing time.
o (2 marks) Discussion of reducing processing delay.
? Part (d)
o (2 marks) Illustration of Manchester Encoding.
o (2 marks) Illustration of Differential Manchester Encoding.
o (3 marks) Explanation of self-synchronization.
o (3 marks) Explanation of DC components and baseline wandering relationship.
o (2 marks) Explanation of how this is resolved by Manchester/Differential Manchester.
? Part (e)
o (2 marks) Reasonable example given.
o (3 marks) Explanation of application of FDM in example.
o (3 marks) Explanation of application of TDM in example.
Question 3 (8 + 12 + 12 + 8 = 40 marks)
? Part (a)
o (2 marks) Datagram network advantages.
o (2 marks) Datagram network disadvantages.
o (2 marks) Virtual-circuit network advantages.
o (2 marks) Virtual-circuit network disadvantages.
? Part (b)
o (1 mark) Identification of first valid reason.
o (3 marks) Explanation of first reason why ARP responses not received.
o (1 mark) Identification of second valid reason.
o (3 marks) Explanation of second reason why ARP responses not received.
o (1 mark) Identification of third valid reason.
o (3 marks) Explanation of third reason why ARP responses not received.
? Part (c)
o (5 marks) Correct application of division.
o (3 marks) Correct quotient.
o (1 marks) Correct CRC code.
o (3 marks) General working.
? Part (b)
o (2 marks) Correct application of addition.
o (2 marks) Correct demonstration of wrapping overflow bits.
o (1 marks) Correct checksum.
o (3 marks) General working.
