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1. Running head: OSI REFERENCE MODEL 1
OSI Reference Model
Sirisha Rayudu
Wilmington University

2. 2
Abstract
These days with advancements in technology large amount data is transmitted so easily
through wires and also wireless. Therefore Data Communication, transfer of analog and
digital data using analog and digital signals gained its importance. This paper brings a model
of data transfer namely OSI data transfer and explains the different layers involved in
transmitting the data from sender to user end. It also brings different protocols and
applications of each of these different layers. Using the seven layers of OSI model I tried to
describe a networking and data communication process.

3. OSI REFERENCE MODEL 3
OSI REFERENCEMODEL
In this global world Networking and Data Communication plays an important role.
Networking is the process of sending data from one computer to other computer. The sending
computer should be able to identify the data, split the data into controllable chunks. Add
material to each lump of information to focus the position of the information and to perceive
the beneficiary. Likewise incorporate timing and sign lapse checking insights. Keep the
information on the system and transmit it on its way. System client software operates at
numerous levels inside of the sending and accepting information correspondence
frameworks. At each purpose of these levels, the employment is reviewed by one or more
conventions. At the point when the sending and accepting correspondence frameworks take
after a one of a kind convention, correspondence taking care of business is said to be
guaranteed. In light of the above talk, two essential arrangements of reference measures were
produced. They are TCP/IP convention suite and OSI model.
In 1978, the International Organization for Standardization (ISO) unconfined an
arrangement of charges that portrays the system construction modelling for interfacing
diverse frameworks. The first report is material to a framework that was interested in
everybody so that they could all utilization the same conventions and qualities to trade data.
In 1984, the ISO accompanied another model and named it, the Open Systems
Interconnection (OSI) reference model. This new overhauled model has turn into a standard
and serves as a building piece for systems administration. The OSI reference model turned
out to be surely understood and most generally utilized model for visualizing system
correspondence and information transmission frameworks. Manufacturers take after the OSI
reference model when they plan systems administration stocks. It brings an unmistakable
picture of how correspondence is made potential.

4. 4
Methodology
The OSI reference model divides network communication and data transmission into
seven layers. Each layer covers different network communication and data transmission
activities.The OSI reference model depicts how each layer communicates and works with the
layers above and below of the networking architecture. The seven layers are listed as follows
OSI Layer Data type Applications/Protocols
Application User data Web browsing, emails, file
sharing and device
redirection.DNS, NFS,
BOOTP, DHCP, SNMP,
RMON, FTP.
Presentation Encoded user data Data formats, compression
and encryptions.SSL, Shells
and Redirectors, MIME.
Session Sessions Session Establishment,
Management and
Termination.NetBIOS,
Sockets, Named Pipes, RPC
Transport Datagrams/segments Multiplexing/DE
multiplexing, Segmentation
and Reassembly,
Acknowledgments and
Retransmissions, Flow
Control. TCP and UDP,SPX,
NetBEUI/NBF.
Network Datagrams/Packets Logical Addressing, Routing,
Datagram Encapsulation,
Fragmentation and
Reassembly.IP, IPv6, IP NAT,
IPsec, Mobile IP, ICMP,
DLC.Routing protocols such
as RIP and BGP.
Data link Frames Data Framing, Addressing,
Error Detection and Handling.
IEEE 802.2 LLC, FDDI, IEEE
802.11, SLIP and PPP
Physical Bits Encoding and Signalling,
Physical Data Transmission,
Hardware Specifications,
Topology and Design.

5. OSI REFERENCE MODEL 5
Networking and data communication process
I would like to describe the seven layers of OSI model applied in the case of sending
email. Here the data is transmitted from sender to receiver through internet. This internet is
network of computers used in data transfer. In a simple sense sending email involves series of
steps for useful communication. The OSI model of sending email is as follows
Application layer
The application layer serves as the scope for users and application practices to access
system services. This layer contains a wide variety of frequently needed functions. For any
task firstly users have to understand what application they want to do. Here the application is
sending email to sender. So this layer specifies the application for the user.
Presentation layer
Once the application is known by the user, the next task is presenting the application.
Here the user has to type the data in email compose box. It can be viewed as the decoder for
the network. This layer translates data from a format used by the application layer into
sending user common format. After this the formatted data is converted to format known to
the application layer at the receiving station.
Session layer
The session layer brings session establishment between processes running on different
locations. It provides maintenance and termination and allows two application processes on
different machines. It manages the data transmitted over email that is,it monitors during the
communication and acknowledges when finished.
Transport Layer
This layer receives signals from session layer in the form of data and this data is made
into smaller data sets and transmits these smaller units into the network. It also ensures that

6. 6
the data transmitted is error free, no duplicates, no loss of data and ensures correct sequence.
It also ensures end to end delivery of data and acknowledgements.
Network layer
This layer controls the operation of the littler information units, choosing which
physical way the information ought to be transmitted, significance of administration, and
different highlights. It likewise gives activity controller to littler information units and
switches can train a sending station to throttle back its casing transmission when the switch's
support tops off.
Data link layer
Once the data from the email is transmitted to the network, the next thing is to link the
different data transmitted over the radio signals to make correct information to be sent to the
receiver. To do this, the data link layer provides data link formation and termination,
establishes and stops the logical link between the nodes. This data is linked to one another by
their IP address.
Physical layer
The last information in the wake of connecting is to be gotten by the collector. The
physical layer, the lower one of OSI model, is restricted with gathering of the unformatted
crude bit information more than a substantial medium. It gives data about the optical,
electrical, mechanical, and useful limits to the real medium, and transmits the signs to the
higher layers. It additionally gives information encoding, deciphers the straightforward
advanced example utilized by the correspondence frameworks for better comprehension the
properties of the physical medium, and to help for synchronization of the information.
Conclusion
From the above theory I conclude that revised OSI reference model is very crucial in transferring data
from one computer to other computer.

7. OSI REFERENCE MODEL 7
References
1) OSI model - Wikipedia, the free encyclopedia. (n.d.). Retrieved May 17, 2015, from
http://en.wikipedia.org/wiki/OSI_model
2) The 7 Layers of the OSI Model - A Webopedia Study Guide. (n.d.). Retrieved from
http://www.webopedia.com/quick_ref/OSI_Layers.asp
3) Open System Interconnection Protocols - DocWiki. (n.d.). Retrieved May 17, 2015,
from http://docwiki.cisco.com/wiki/Open_System_Interconnection_Protocols