Computer Networks: A Comparative Study of OSI and TCP/IP

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ASSIGNMENT 1
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1)
OSI
The systems which are open and interconnection (OSI) model and is a conceptual model that
is used to standardize and characterize the functions of communication of a computing
system or telecommunication without its underlying structure or internal technology.
(Wilkins, 2011)
OSI Model includes 7 layers which are given as follows: -
i) Layer 7 - The Layer of Application
ii) Layer 6 - The Layer of Presentation
iii) Layer 5 - The Layer of Session
iv) Layer 4 - The Layer of Transport
v) Layer 3 - The Layer of Network
vi) Layer 2 - The Layer of Data Link
vii) Layer 1 -The Layer of Physical
Figure 1: OSI Model

TCP / IP: -
The TCP / IP are layered model and are used for fashion same as OSI and are having few
layers than the OSI model. The latest web or internet or other communication method uses
internet protocol. It is more in line as the modern implementation of the network.
i) The layer of link
ii) The layer of the internet
iii) The layer of transport
iv) The layer of application
2)
On comparing the models of the TCP/IP and OSI, the systems that are open and are
interconnection (OSI) consisting of 7 layers and TCP/IP is similar to OSI but have fewer
layers than OSI. There are mainly 4 layers in the TCP/IP.
In OSI according to the diagram from the top of the application layer having the applications
that use network services and to the bottom of the diagram, the physical layer consists the
types of connector and cable, the topology for the network as a bus or ring. OSI converts the
formats of network communication that can be used by the application with formats .png, .jpg
and .gif. It is converting the communication network formats into the format of text such as
EBCDIC and ASCII. (Steve, 2019)
In TCP/IP, there are 4 layers whereas the OSI has seven layers. The main function is
performed by the top three layers of OSI which are then combined with the application layer.

Session layer of TCP/IP layer synchronizes the exchange of data between the different
network device for example socket, which is combined into various layers of applications of
TCP/IP. (Bucaro, 2019)
Figure 2: OSI and TCP/IP suite
3)
In TCP/IP suite protocol the layers which are network support layers are : -
i) Network interface Layer ( layer 1)
ii) Internet Layer ( layer 2)
The layers which are user support layers are: -
i) Transport layer (layer 3)
ii) Application layer (layer 4)
4)
Data encapsulation is defined as the mechanism where the details of the implementation of
the class are to be made hidden from the user. Data encapsulation is also known as data
hiding. The user must be able to perform very few and restricted operations on the member

that is hidden by the class by the execution of a special function that is commonly known as
methods.
It may be referred to as the isolation of private data in a class in an object-oriented language
of programming from the user.
OSI model uses data encapsulation in network protocol.
Like the layers of TCP/IP, the layers of OSI require the services from lower layers. The
layers lower to the above layer are encapsulated the data of higher layers between header.
While in the TCP/IP suite uses the terms like a packet, frame, and segment for referring to the
packet of data that defines a layer and the models of OSI uses the terms as Protocol data unit
or PDU. (Geek University, 2019)
5)
The data link is the 2nd layer on the systems that are open and are interconnection or OSI
among all the seven layers of the OSI model. The service requests that belong to the network
layer are the result of the response from data link which is above all and the requests of
service having issues to the layer below it which is the layer of physical.
The responsibility of the data link is controlling link that is logical, hardware defining,
addressing, and handling standards of physical layer and control on media assets. Data link
provided the data transfer from transmitting of the packets by necessary synchronization,
flow control, and error control.
It is also responsible for the process of encoding bits into the packet that will be decoded
further and converts back packets into the basic information unit that is bits in
communication and computing. The fundamental information transfer unit is packets in
modern networks of computer and is at the growth stage in another network also.
(tutorialspoint.com, 2019)
6)
Transport layer Network layer
The layer of transportation is used to make a The major function of the layer of

path for the message that moves from source to
destination.
transport is for delivering the packet
from one end that is a source to another
end that is a destination.
Relationship between the layer of transport and
the data link is :
Relationship between the network layer
and the data link is : -
The layer of transportation is connection-
oriented as well as connectionless.
It provides network flow chart layer,
packet control sequence, error control
network layer, and connection services.
Its main purpose is dividing the message into
small packets before source and assemble the
packets in a specific order before reaching the
destination.
It helps in translating the address of
logical network into the physical address
of the machine. i.e. destination id uses
the numbers in the physical car of the
network.
(Juilee, 2012)
7)
Data link protocol layer present in the program that handles the moving of data from the
physical layer. The major benefit of data links in the networking system to provide
modularity.
The following features are involved in the data link layer: -
1) Error correction and detection
2) Some kinds of status of health for the link

3) For accessing the media, reducing the interference while accessing various messages
from multiple numbers of transmitters.
4) Media that is connection-oriented, management, connection setup, and teardown.
5) Framing, packetization, and channelization, etc.
8)
The network layer 3rd layer from downward in a system that is open and is the
interconnection model that comprises of seven layers.
The layer of the network where the Internet protocol is operated. Other protocols in TCP/IP
which forms internet basics and other networks.
The main important function of the layer of the network is to carry all the messages into
packets through the appropriate path. Firstly, the message is converted into packages and is
carried from source to the destination through the network .it also results in translation of
logical addresses.
In contrast to the data link that is responsible for delivering the packets with mac address.
(Bhatia, 2019)
9)
Transport layer as the name suggested is much responsible for solid communication that held
between two or many. It is an interconnection between various layers that are connected to
one another. The architecture is followed by different hosts that help in logical
communication between various application processes.
It is also responsible for managing quality, end-user reliability and error connections .this
enabling the host to receive and send corrected data message on network or packet on a
network and allows multiplexing as being the network component.
Service provided by the transport layer: -
1) Byte orientation
2) Multiplexing
3) Flow control

4) Traffic control
5) Same order delivery
6) Data integrity
7) A connection which is connection oriented
(“Transport Layer Protocol - an overview | ScienceDirect Topics,” 2013)
10)
Port address: - There is the various application of different kind that runs on a computer. the
kernel of the operating system for individual application decides the port number of each
application. This port number is also known as port address.
Logical address: -The IP address every computer system have is known to be a logical
address. This address is a combination of the net identification number and host identification
number. It is used for identifying a network among a various group of networks by using
certain algorithms for network selection it may depend on the strength of the network. The
address can easily be changed by just altering the position of the host over the network;
Physical address: - Every and every system has a (NIC) network interference card using
which 2 or more systems can be connected physically to each system and can exchange data
easily by using cables as the data transfer path. Address in the NIC is also known as MAC
address or physical address. All these things are provided by the card manufacturer. This
address can be further used as the layer of datalink.
11)
The application layer is defining the standards of the service of the internet and the
application of the network that is used by everyone. These services are associated with the
layers of transport for sending and receiving essential data in assistance with the protocol of
application layers. The examples of the application layer are shown below: -
 Network management activated by (SNMP) Simple Network Management Protocol
 Standard services of TCP/IP such as the commands TFTP, telnet, and FTP
 (RDISC) Router Discovery Server protocol and (RIP)Routing Information Protocol
routing protocols
 Services, like domain name system (DNS) and NIS
 UNIX “r” commands like RSH and Rlogin

 (LDAP Directory services)
 NFS service of File services
(Goswami, 2019)
12)
By the combination, all the layers like Presentation, Application layers and Session of the
OSI to a single layer is done by reducing overhead and single layer. Its major disadvantage is
that more functions are to be performed by just a single layer.
Advantages of the combination are: -
a) All the functionality is provided in a single layer; therefore, the study of a single layer
is to be done.
b) Bandwidth is very high as the reduction of a number of layers are done.
c) It is capable of reflecting the separation of application based on real life. The
application is from the section down to the TCP suite of OSI model.
Disadvantages of the combinations are: -
a) Reasoning to be made about the network system architecture less effective.
b) The issues for the security as per the application and network security.
It makes various steps like troubleshooting very hard as multiple numbers of error are present
at a single layer. (Kumar, 2014)

Reference: -
 Bhatia, V. (2019). Explain the functions of the network layer? | Practice |
GeeksforGeeks. Retrieved May 9, 2019, from Geeksforgeeks.org website:
https://practice.geeksforgeeks.org/problems/explain-functions-of-network-layer
 Bucaro, S. (2019). Comparison of the Layers of the OSI and TCP/IP Models.
Retrieved May 9, 2019, from Bucarotechelp.com website:
http://bucarotechelp.com/networking/standards/87090502.asp
 Geek University. (2019). Data encapsulation in the OSI model | CCNA. Retrieved
May 9, 2019, from Geek University website: https://geek-university.com/ccna/data-
encapsulation-in-the-osi-model/
 Goswami, M. (2019). Application Layer Protocols: Types & Uses | Study.com.
Retrieved May 9, 2019, from Study.com website:
https://study.com/academy/lesson/application-layer-protocols-types-uses.html
 Juilee. (2012). Difference between network layer delivery and transport layer
delivery. Retrieved May 9, 2019, from Ques10.com website:
http://www.ques10.com/p/5405/difference-between-network-layer-delivery-and-tr-1/
 Kumar, V. (2014, January 27). What is the difference between port address, logical
address and physical address? Retrieved May 9, 2019, from 2IT414-Distributed
Systems website: https://2it414vkp.wordpress.com/2014/01/27/what-is-the-
difference-between-port-address-logical-address-and-physical-address/
 steve. (2019, April 18). The TCP/IP Model and Protocol Suite Explained for
Beginners. Retrieved May 9, 2019, from Steves-internet-guide.com website:
http://www.steves-internet-guide.com/internet-protocol-suite-explained/
 Transport Layer Protocol - an overview | ScienceDirect Topics. (2013). Retrieved
May 9, 2019, from Sciencedirect.com website:
https://www.sciencedirect.com/topics/computer-science/transport-layer-protocol
 tutorialspoint.com. (2019). DCN Data-link Layer Introduction. Retrieved May 9,
2019, from www.tutorialspoint.com website:
https://www.tutorialspoint.com/data_communication_computer_network/
data_link_layer_introduction.htm
 Wilkins, S. (2011). OSI and TCP/IP Model Layers | OSI and TCP/IP Model Layers |
Pearson IT Certification. Retrieved May 9, 2019, from Pearsonitcertification.com
website: http://www.pearsonitcertification.com/articles/article.aspx?p=1804869