MITS4004 Assignment 1: A Comparative Analysis of OSI and TCP/IP Models

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MITS4004
Assignment 1

Contents
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Reference.........................................................................................................................................8
List of tables
Table 1: Difference: Network and Transport layer delivery...........................................................5
Table 2: Differences between port address, logical address, and physical address.........................6

1.
OSI model is presented with a number of 7.0 layers which are used in distributing the
communication that takes place between two points of a network. They are-
 Layer 1.0- It is defined as Physical layer.
 Layer 2.0- It is defined as Data link layer.
 Layer 3.0- It is defined as Network layer.
 Layer 4.0- It is defined as Transport layer.
 Layer 5.0- It is defined as Session layer.
 Layer 6.0- It is defined as Presentation layer.
 Layer 7.0- It is defined as Application layer.
TCP/IP protocol suite is presented with a number of 4.0 layers which are used in establishing
communication between two points. They are-
 Layer 1.0- It is defined as Physical layer.
 Layer 2.0- It is defined as Network layer.
 Layer 3.0- It is defined as Transport layer.
 Layer 4.0- It is defined as Application layer (Forouzan, 2002).
2.
OSI and TCP/IP are both developed to assist in the process of communication in a network. The
layers in both the OSI and TCP/IP model are inter-related as they were developed to serve the
same purpose in a network system, such as-
 Application layer in TCP/IP model is combined to serve all the purpose of the OSI’s
Application, Session, and the Presentation layer.
 The Physical layer of the TCP/IP protocol suite assists with the goals of both the Physical
and the Data link layer in OSI.
 Network layer and Transport layer of the TCP/IP model serves the same propose as of the
Network layer and Transport layer represented in the model of OSI (Briscoe, 2000).

3.
In TCP/IP model, the network support layer includes Network layer and Transport layer.
Network layer deals with the communication packets and helps in the transporting of these
packets across various autonomous networks. Transport layer provides support to the network by
managing the point-to-point communications that are processed across various networks.
The user support layers in TCP/IP model include Physical layer and Application layer. The
Physical layer deals with the components that process the communication by which hosts or
nodes in network interconnects. The Application layer handles the data exchange process by
providing applications which standardize the process of exchange of data (Forouzan, 2002).
4.
Encapsulation is the process of enclosing specific components in a different component such as
in capsules. In network systems, there are various packets which are used in establishing
communications across the networks. These packets comprise headers in which the addresses of
receiver and sender are encoded and the body in which the main data that is to be transferred.
Data encapsulation is the process of adding and removing such headers that are present in the
packets that travel in each layer in OSI or TCP/IP model. The process of adding and removing
specific header files processes the communication of the data in the network to accomplish the
process of communication (Goralski, 2017).
5.
Data link layer is layer 2.0 in OSI and is used to arrange links around physical network by
inserting packets into the frames of the network. The responsibilities of Data link layer includes
the process of bits encoding into packets that are to be transferred across the network and the
decoding of the packets into bits in the endpoint. This layer is also responsible in managing the
LLC (Logical Link Control), detection and handling of errors, MAC (Media Access Control),
addressing of hardware and also in the defining the standards of the physical layer
(AfiqahAzahari, Al-Hubaishi, and Uddin, 2013).

6.
Table 1: Network and Transport layer delivery difference
Transport layer Network layer
Delivers the whole message from one point to
the other.
Delivers only the packets from one point to the
other in multiple networks.
In this layer, the messages to be transferred are
distributed into packets, delivered to the
destination, and reassembled the message in
the endpoint.
In this layer, the logical address of a network is
transformed into the mechanical address and is
used as an endpoint address in the cards of
physical networks.
The delivery process of transport layer can be
with or without connections.
Network layers provide the connection services
which includes sequence controls of packets,
controls the flow of the network layer, and also
measures the errors present in this layer.
7.
Data link layer, to detect errors, uses the data frames and bits and creates packets of data in order
to process the transmission. In this, data link layer inputs address of origin and destination along
with a system to detect the errors in the transmission. The requirement of another mechanism to
detect errors at the transport layer arises as the data link layer can only detect errors in between
hops and are not able to detect errors that are present at the nodes. Data link layer also tends to
lose the integrity of the data that is transmitted using this layer (Wang, Hao, & Hanzo, 2016).
8.
The network layer is layer 3.0 in the OSI model and the layer 2.0 in TCP/IP model which is used
in managing of the data packets and routing of the packets to the destined location. The
responsibilities of the Network layer includes routing, which includes moving of the data packets
through the network to their destination by using the best available path. The Network layer is
also responsible for addressing a message in which the addresses are translated to a physical
address from a logical address. Network layer also detects errors by using the protocols
integrated into the layer.

9.
The responsibilities of Transport include the management of step-to-step delivery in which the
layer determines the port number of the data and commences transportation of the data to the
correct destination. Transport layer is also responsible for handling the integrity of the data and
correcting the errors present in the data packets using codes of error detection and checksums.
Transport layer is also responsible for managing congestions that occurs in the network in which
it uses the process of open loop control to prevent congestions and closed-loop control to
eliminate the congestions that are already present in the network (Forouzan, 2002).
10.
Table 2: Differences within logical address, port address, and physical address.
Port address Logical address Physical address
It is the port number of an
application or a program that
uses the network for
communication
It is the virtual address of an
application or a program
which uses the network for
communication.
It is the NIC address present in
an application or a program
that use network for
communication.
It is used in the identification
of the application of system
that is based in a particular
network.
Network layer uses this
address to identify specific
network amongst various
networks.
Data link layer to use this
address to determine which
device is connected and linked
to the network.
11.
Services provided by the Application layer includes-
 Standard TCP/IP services- It includes services such as FTP (File Transfer Protocol) and
TFTP (Trivial FTP). FTP helps in the transferring of files from one network to a different
remote network. TFTP provides similar functions as provided by FTP but eliminates the use
of connections that are interactive, hiding the contents present in the directory.

 Directory services- It includes the use of Lightweight Directory Access Protocol (LDAP)
which helps in differentiating themselves from the name services. The processing of LDAP is
similar to name services, including added functionalities (Goralski, 2017).
12.
The advantages of combining the three layers of OSI to a single layer in the TCP/IP model
include the decreased time interval taken between two points. This process also enhances in the
performance by inducing less queuing interval in establishing communication within two
endpoints as the transmission of packets will take place in a single layer, hence improving the
performance tuning of packet transfer. Other advantages of combining layer 5.0, 6.0, and 7.0 of
OSI include the reduction of data amount in datagrams. This process will also provide higher
bandwidth to the system as the amounts of the layers are reduced in the TCP/IP protocol suite
(Goralski, 2017).

Reference
AfiqahAzahari, R.A., Al-Hubaishi, M. & Uddin, M. (2013). Review of error detection of data
link layer in computer network. Middle-East Journal of Scientific Research, 18(7), pp.968-973.
Briscoe, N. (2000). Understanding the OSI 7-layer model. PC Network Advisor, 120(2).
Forouzan, B. A. (2002). TCP/IP protocol suite. McGraw-Hill, Inc..
Goralski, W. (2017). The illustrated network: how TCP/IP works in a modern network. Morgan
Kaufmann.
Wang, X., Hao, P., & Hanzo, L. (2016). Physical-layer authentication for wireless security
enhancement: current challenges and future developments. IEEE Communications
Magazine, 54(6), 152-158.