top-rated free essay

The Osi Model

By jenbranson Jan 02, 2006 550 Words
The OSI Model

NTC/360 Network & Telecommunications Concepts

The OSI Model
The Open Systems Interconnection Reference Model (OSI) is the accepted model that describes the how the communications for a computer network should be designed. OSI was developed as part of the Open Systems Interconnect Initiative. Basically, OSI divides the functions of a protocol in to seven layers. This makes the reasoning easy to follow and the system much more reliable. The implementation of several OSI layers is often referred to as a Stack or a TCP/IP Stack. The layers are often referenced in descending order because layer 7 is the first layer that an end user sees. A detail of each layer in descending order follows: ·Layer Seven of the OSI Model - The Application Layer of the OSI model is responsible for providing end-user services, such as file transfers, electronic messaging, e-mail, virtual terminal access, and network management. This is the layer with which the user interacts. ·Layer Six of the OSI Model - The Presentation Layer of the OSI model is responsible for defining the language that enables two network hosts to communicate. Encryption and compression should be Presentation Layer functions. ·Layer Five of the OSI Model - The Session Layer of the OSI model is responsible for establishing process-to-process communications between networked hosts. ·Layer Four of the OSI Model - The Transport Layer of the OSI model is responsible for delivering messages between networked hosts. The Transport Layer should be responsible for fragmentation and reassembly. ·Layer Three of the OSI Model - The Network Layer of the OSI model is responsible for establishing paths for data transfer through the network. Routers operate at the Network Layer. ·Layer Two of the OSI Model - The Data Link Layer of the OSI model is responsible for communications between adjacent network nodes. Hubs and switches operate at the Data Link Layer. ·Layer One of the OSI Model - The Physical Layer of the OSI model is responsible for bit-level transmission between network nodes. The Physical Layer defines items such as: connector types, cable types, voltages, and pin-outs. The layers have the several characteristics in common. Eeach layer is separate and independent and each layer serves a purpose and provides support to the layers above and below it. Using the model ensures that the software and hardware work together to producing a functional and efficient experience. When two devices are communicating, each layer interacts with the same layer in the other device. When data is sent from the application on the source computer the following happens. Data in the form of a packet moves down through the layers. When it reaches the Physical Layer it is ready to be sent along the cable. At the Physical Layer the bits may be analogue or digital. The data is transmitted to the destination device. It travels up through the layers of the OSI model, reaching the user. As data moves down through the layers it is encapsulated. Additional information is added as headers or trailers. The data in the packet does not change. In short, the OSI model is an international tool that enable computer to share information. Since being released in 1984, the OSI model has been useful in defining and describing networking communications in the business world and beyond.

Cite This Document

Related Documents

  • Osi Model

    ...Michael Rauseo IT310 OSI Model In the early years of computer and network research and development many systems were designed by a number of companies. Although each system had its rights and were sold across the world, it became apparent as network usage grew, that it was difficult, to enable all of these systems ...

    Read More
  • Osi Model for It Professionals

    ...the OSI Model? The OSI model is a reference model which most IT professionals and network applications. use to describe networks The OSI model was originally intended to describe a complete set of production network protocols, but the cost and complexity of the government processes involved in defining the OSI network made the project unviable....

    Read More
  • 7 Layers of the Osi Model

    ...The Seven Layers of the OSI Model Kevin Ludwig Bryant and Stratton College TECH 140 Khaled Sabha 12.08.2009 There are seven layers in the OSI model. Each layer has a function or purpose that is used to set up a network. The International Organization for Standardization began to develop the OSI framework in 1984. The purpose was t...

    Read More
  • The Session Layer of the Osi Model

    ...A Glance at the Session Layer of the OSI Model Throughout the history of networking, one model has stood the test of time for providing not only insight, but also a foundation by which all networking systems utilize in some form or fashion. The seven layers of the OSI model, which stands for Open System Interconnect, are: Application, Present...

    Read More
  • Layman View of Osi Reference Model

    ...Layman View of OSI Reference Model (By Diganta Deka, Former Student, Proprietor-Trainer East India Technologies, Guwahati.), diganta.deka@hotmail.com When we talk about computer networks and how computers operate in networks, things do not remain as simple as it seems to be. Here numerous protocols work in tandem for the s...

    Read More
  • Open Systems Interconnection (Osi) Model

    ...OSI Model This memorandum will attempt to explain the Open Systems Interconnection Model, known more simply as the OSI Model. The OSI Model has seven levels, and these levels will be discussed in detail. Particular mention will be made to which level TCP/IP functions with the OSI Model. The seven levels of the OSI Model are as follows: 7)...

    Read More
  • Osi Model with Its Seven Layers

    ...Friday, September 24, 2010 JANN VINCENT PAUL C. LAGMAY BSIT-1A Open System Interconnection (OSI) The Open System Interconnection Reference Model or OSI Reference Model or OSI Model is essentially a conceptual description for layered communications and computer network protocol design. It was created as part of the Open Systems Interconne...

    Read More
  • Understanding the Osi Model

    ...Understanding the OSI Model November 26, 2012 Understanding the OSI Model The Open Systems Interconnection (OSI) Model is a reference tool for understanding data communications between any two networked systems (Simoneau, 2012). The OSI Model dissects the communication process down to seven layers, where each layer performs specific fu...

    Read More

Discover the Best Free Essays on StudyMode

Conquer writer's block once and for all.

High Quality Essays

Our library contains thousands of carefully selected free research papers and essays.

Popular Topics

No matter the topic you're researching, chances are we have it covered.