Functions of Each Layer of OSI Reference Model and Difference Between Hardware and Software Layers

This article explains the functions of each layer of the OSI reference model and the difference between hardware and software layers. It also discusses why the network layer of the OSI model is called the internet layer in the TCP/IP networking model.

Assessment No
Assessment Title
Student Name & ID
Subject Name and Code
Student Email Address

Question 1 [3 Marks]
Write functions of each layer of OSI reference model, also differentiate between hardware and software layers.
Explain your view; why Network layer of OSI model is called Internet layer in TCP/IP networking model?
Information exchange happens between two or more devices on a network. The devices
involved are of several types and have different functions. Data has several different formats. To
make communication possible, all these involved parties need to agree on a common standard
for information exchange. That standard is arranged in layers and is called as OSI reference
model. It comprises of 7 different layers.
Starting from Top Layer is
 Layer 7 Application Layer: This layer is
the graphical/ command line interface
between user and rest of the network.
User interacts with networks using
commands via this layer and received
information over this layer.
 Layer 6 Presentation Layer: The layer
deals with data formats. Each
application may have different formats
for data. The layer manages between
data format interpretation and
packaging for remote location.
 Layer 5 Session Layer: The layer manages a communication channel between client
and host. It keeps track of data that is transferred with surety. The session layer keeps
the machines connected or alive even when data is not being transferred between two
devices.
 Layer 4 Transport Layer: The layer makes sure that data received is correct and error
free. In case data packet is corrupt, the layer discards the packet and requests
retransmission. The layer also performs data segmentation for large data packets not
supported by underlying infrastructure. The same layer also performs data reassembly
for received packets.
 Layer 3 Network Layer: This layers handles a globally unique address for the device.
This address enables data packet to be transferred among machines without ambiguity
about destination. In network layer, only deals with individual packet. It is not concerned
about overall payload that might be fragmented across several packets.
 Layer 2 Data Link Layer: This layer manages point to point communication between
devices. The data received from Network layer is forwarded to physical layer. Any flow
control as necessary may also be performed by this layer. It prevents collisions during
transmission of data and enables re-transmission in case of collision.
 Layer 1 Physical Layer: This is a medium dependent layer but its functions is same. It
encodes binary data into electrical/Optical/Wireless signals suitable for transmission on

attached medium. It’s only responsible for bit by bit data. Any error in received packet
are dealt with at upper layers and not by this layer.
As mentioned in figure above, the lower 3 layers deal more with packet data and its routing over
the network hardware. While top 3 layers are transparent to underlying network infrastructure
and deal with data and its manifestation to the user at software level.
Internet layer in TCP model owns the globally unique address to maintain an device to device
level communication, this is same function as network layer in OSI model. Thus internet layer is
also called network layer of TCP/IP.

Question 2 [3 Marks]
Complete the following Hands-On Projects from the prescribed textbook (Pyles, Carel & Tittel 2017)
Hands-On Project 2-3
Added LAN address in the software and selected Max subnets as 32 to get list of subnets

Hands-On Project 3.2
In order to complete this activity, students should insert screenshots in the assignment document along with a short
description of each step taken to complete the project.
Ping to Google IPv6 Address
Ping Packet Expanded to reflect Version IPv6

Traffic class for the packet
Packet Pay load and Hop limit, other parameters

Question 3 [4 Marks]
For any data communication, MAC and IP addresses play very important role, explain why these two types of
address are important and what critical role ARP protocol plays in this scenario?
MAC address is pre-defined address for the node at data link layer while IP address is a
user configurable address at Network layer. MAC is unique only with in local network
and hence is capable of Point to Point communication only while IP is globally unique
and hence can allow communication across entire network.
When communicating with a device across local network, only the IP address of the
other device is known via DNS query. To forward the packet to actual receiver, its MAC
address also needs to be known. ARP helps in resolving this request. Device in need of
a MAC address of a known IP address can broadcast an ARP Request. The device with
matching IP address sends ARP reply packet with their MAC addresses. This way MAC
and IP addresses allows smaller networks to connect to each other via address
resolution protocols with the help of ARP protocol.

Question 4 Case study task [5 Marks]
In your role as a Solutions Architect at Foreshore IT Solutions, you are leading a team of several system
administrators. Foreshore IT Solutions is a large organisation and is currently expanding its operations. The company
was using six sites across Brisbane to accommodate its various departments. These departments are interconnected
by three routers.
Company’s current network is shown as above, which include following departments at various sites:
Site Department No of Hosts
HQ Sales 16000
Marketing 8000
BR1 Advertising 2000
Online Sales 4000
BR2 Product Support 1000
Technical Support 500
Recently, company has experienced huge growth in their business, and need to employ more employees who will
need more devices (hosts). Company is expecting 40% growth.
You are required to recalculate IP addressing scheme for this network to accommodate 40% growth, for example;
Sales department will grow by 6400 hosts. Also provide subnets for inter router connections which should have
subnet mask 255.255.255.252
Use network ID 180.XY.0.0/16 (where XY are last digits of your student ID). 11643188
TASK - Write a 800 words (+/- 10%) (Max) report explaining:
The detailed design of a simple addressing solution (with diagram(s) and step by step workout of the calculations)
that accommodate for growth, is easy to administer and has the minimum wastage of available IP address space. [3
Marks]
Provide IP addresses and Subnet Masks for all LAN and WAN interfaces. [1 Mark]
Suppose in further future, this company experience more growth, which leaves company with no option except
upgrading this network from IPv4 to IPv6, investigate/explore the technical changes you may need to implement for
such upgrade
Rationale
This assessment aims to assess the following learning objectives of this subject:
be able to analyse IP addressing requirements and design an addressing scheme;
be able to analyse the requirements of IP routing and choose appropriate routing methods;
be able to demonstrate how internetworking devices obtain their network configuration;
be able to explain how data flows through the internet; and
be able to ascertain and evaluate selection of applications and protocols for transferring data across the internet

The current count of employees at the Foreshore IT solutions is huge and is still
expanding. Looking at the future, they need a plan for their network infrastructure in
terms of IP address assignment. The assignment should be such that each department
is capable of communicating with each other without hassle but for security reasons,
departments other than their own, should ask for permissions from administrator to
allow access. Based on requirements for each department at various branches, the
following IP address allocation is proposed for the Foreshore IT solutions:
Department Number
of
Hosts +
40%
Nearest Subnet
Mask
First Host IP
Address
Last Host IP
Address
Usable
hosts
Sales 22400 255.255.128.0 180.88.0.1 180.88.127.254 32766
Marketing 11200 255.255.192.0 180.88.128.1 180.88.191.254 16382
Online
Sales
5600 255.255.224.0 180.88.192.1 180.88.223.254 8190
Advertising 2800 255.255.240.0 180.88.224.1 180.88.239.254 4094
Product
Support
1400 255.255.248.0 180.88.240.1 180.88.247.254 2046
Technical
Support
700 255.255.252.0 180.88.248.0 180.88.251.254 1022
Router HQ To BR1 255.255.255.252 180.88.255.241
To BR2 180.88.255.245
Router BR1 To HQ 255.255.255.252 180.88.255.242
TO BR2 180.88.255.250
Router BR2 TO HQ 255.255.255.252 180.88.255.246
To BR1 180.88.255.249
First Host IP address is assigned to respective Router interfaces for each LAN and is
also the default Gateway address for each of the LANs. Multilayer switch network has to
be designed for access across the department in each LAN.

Nearest subnet mask has been used to allow maximum IP address utilization without
wasting non used IP Addresses. Rounding each group to nearest subnet still leaves lot
of room for future expansion in all branches apart from the required 40% growth.
Routers have been allocated last IP address from range to allow more departments
within organization without changing Router addresses or allow expansion of already
present departments.
Migrating to IPv6 needs supporting Routers and Ethernet NIC cards. It is assumed End
devices already have support for IPv6. However Routers and switches need to support
IPv6 addresses. The firm has two options either to choose IPv4 devices for now and
upgrade to IPv6 devices later on. Otherwise the firm can make use of dual stack routers
supporting both versions and save on hardware cost as well as implementation cost in
long run.
Bibliography
layers-osi-model. (n.d.). Retrieved from https://www.geeksforgeeks.org:
https://www.geeksforgeeks.org/layers-osi-model/
Stallings, W. (n.d.). DATA AND COMPUTER COMMUNICATIONS. In W. Stallings. Pearson Prentice Hall.

Rationale
back to top
This assessment task will assess the following learning outcome/s:
be able to analyse IP addressing requirements and design an addressing scheme.
be able to analyse the requirements of IP routing and choose appropriate routing methods.
be able to demonstrate how internetworking devices obtain their network configuration.
be able to explain how data flows through the internet.
be able to ascertain and evaluate selection of applications and protocols for transferring data across the internet.
This assessment aims to assess the following learning objectives of this subject:
be able to analyse IP addressing requirements and design an addressing scheme;
be able to analyse the requirements of IP routing and choose appropriate routing methods;
be able to demonstrate how internetworking devices obtain their network configuration;
be able to explain how data flows through the internet; and
be able to ascertain and evaluate selection of applications and protocols for transferring data across the internet.
Marking criteria and standards
back to top
HD
DI
CR
PS
FL
Question 1
In depth use of a good range of relevant literature to address the points. Provides a comprehensive comparison of
OSI reference model with TCP/IP networking model, with evidence of synthesis of own research and prescribed
reading in topics.
Evidence of using relevant literature to address the points. Provides a detailed comparison of OSI reference model
with TCP/IP networking model, with evidence of synthesising some external readings and prescribed reading in
topics.
Use of some relevant literature to address the points. Provides a good comparison of OSI reference model with
TCP/IP networking model. Mostly cited the prescribed text. Synthesised concepts learned from topic readings.
Limited evidence of using relevant literature to address the points. Provides a brief comparison of OSI reference
model with TCP/IP networking model with little evidence of linkages or connections to topic readings
No evidence of using relevant literature to address the points. Provides an incomplete comparison of OSI reference
model with TCP/IP networking model with no linkages or connections to topic readings.
Question 2
Projects are completed, screenshots of all steps along with informative description has been provided.
Projects are completed, screenshots of most steps has been provided with good description
Project mostly completed, some minor errors are apparent in the screenshots, description i
Project completed but with errors, some screenshots are missing, description is not clear
Evidence of some steps, most screenshots are missing.
Question 3
Clear, comprehensive description of ARP. Critical points identified & discussed.
Detailed description of ARP. Many critical points identified & discussed.
Good description of ARP. Some critical points identified & discussed.
Some description of ARP. Some critical points identified & discussed with some inaccuracies or omissions.
Incomplete or inadequate description of ARP. No critical points identified or discussed.
Question 4
Provides a complete, clear, and detailed, step-by-step description of IP addressing requirement analysis and design
that fully and accurately fulfills the requirements. Diagram/s are appropriate and accurate. Identifies and analyses all
critical points.
Provides a detailed, step-by-step description of IP addressing requirement analysis and design that and accurately
fulfils the requirements. Diagram/s are appropriate and accurate. Identifies and analyses most critical points.
Provides a detailed description of IP addressing requirement analysis and design that accurately fulfils the
requirements. There are some inaccuracies or omissions. Diagram/s are appropriate and mostly accurate, with some
minor inaccuracies or omissions. Identifies and provides some explanation for most critical points.

Provides a complete but superficial description of IP addressing requirement analysis and design. Diagram/s are
appropriate and mostly accurate, but there are inaccuracies or omissions Identifies and provides explanation for only
one or two critical points.
Does not provide a complete description of IP addressing requirement analysis and design Diagram/s are inaccurate,
or not included. No critical points identified and discussed.
Presentation
back to top
The assessment must be submitted electronically with a Cover Page that includes the following information:
Assessment No
Assessment Title
Student Name & ID
Subject Name and Code
Student Email Address
Students must ensure that all tasks/questions are identified clearly with headings.
Answers to the questions must be in your own words and should be precise but complete and informative. No marks
will be awarded for any answer containing more than 10% direct quotes (referenced or unreferenced).
APA reference style must be used throughout the document with the bibliography at the end of the document. In-text
citations should also follow APA style. APA referencing guide can be accessed via the following link. This also forms
a part of the marking rubric.http://student.csu.edu.au/study/referencing-at-csu
Please note: Assessment MUST be submitted as ONE MS Word file via Turnitin. Please do not submit *.zip or *.rar or
multiple files. Assessments are marked and feedback is attached using a MS Word-based tool. Reports that are
submitted in PDF format will be re-formatted to Word format in order to be marked. Allowances will not be made for
any loss of information, diagrams or images as a result of the re-formatting