Running head: OSI REFERENCE MODEL 1

OSI Reference Model

Sirisha Rayudu

Wilmington University

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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.

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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.

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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.

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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

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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.

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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