Networking Simplified - Part 05
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  1. #1
    er0k
    Guest

    Networking Simplified - Part 05

    This is the fifth edition to my series entitled "Networking Simplified."
    In this edition, I will go over the OSI model, as promised. The OSI model
    will take up the entirity of the tutorial, so keep in note that Networking
    Simplified 5 is OSI only for your own personal reference.


    First i will begin with simply listing the layers as mentioned in the 4th
    series.

    _____________________________

    Layer 1 - The Physical Layer

    Layer 2 - The data-link Layer

    Layer 3 - The Network Layer

    Layer 4 - The Transport Layer

    Layer 5 - The Session Layer

    Layer 6 - The Presentation Layer

    Layer 7 - The Application Layer

    ________________________________


    Layer 1 of course, the physical layer, is exactly what it sounds like.
    Whether you are speaking in terms of a router, a hub, a switch etc this is
    what provides that hardware with the ability to pass and receive the data
    on its line. The mechanics and electricty of such provide for this.


    Layer 2. This layer is basically what links the hardware's jobs to the
    network. It is what allows transmission ports to be able to go. It is
    somewhat of a timer theoretically speaking, as it synchronizes data when
    linking, hence the name, data-link layer.

    Layer 3. The network layer is possibly the most known of layers. Whether
    because of its easy to remember name since the term network is so vastly
    known, or because it is what handles the packets. The packets are routed
    along to the correct destination on the network going outward, while still
    receiving the transmissions of packets. The job of this layer is to
    forward data and route it.


    Layer 4. The transport layer is a simple one in which all it does is
    check for errors of packets. If they have arrived, it can forward them
    further and along to complete the transfer.

    Layer 5. The Session Layer. This is the layer that enables you to talk on
    your instant messaging programs, your Internet Relay Chat, your anything
    real-time. What it does is allows for dialogs by coordinating the
    applications as they go.

    Layer 6. The Presentation Layer. This layer is commonly found built-in
    operating systems. Commonly called the syntax layer, because of the way it
    handles the data presentation. It can send your php code across the
    internet and have it bring up an advertisement. It is exactly what it
    says, a presentation format that changes presentation of the stream to the
    desired format.

    Layer 7. The application layer.. The most "used" so to speak layer by the
    end user. It in itself is what provides for user authentication across the
    net. It handles encryption, it handles data formats of all shapes and
    sizes. Bear in mind that the term "application" does not necessarily mean
    a program. It simply means that this is where the finality of all the data
    processing finishes, if its desired destination is this far. Communication
    works here through a partnership. Sometimes referred to as a hand-shake.

    OSI was developed by telecommunication companies in the early eighties.
    Finally after years of experimentation and morphing, it became known as
    the ISO, or International Organization of Standards. (Not to be confused
    with software isos.) Its original intent was just to provide for chosen
    interfaces. It transformed into the reference layer and how the internet
    processes data.

    This concludes my 5th tutorial, as the OSI model is so vast. I will
    include some links below for further reference, as these tutorials cannot
    provide for the ability of making a user interaction with pictures and so
    forth.


    http://www2.rad.com/networks/1994/osi/intro.htm

    http://www.erg.abdn.ac.uk/users/gorr...pages/osi.html

    http://webtraining.infoworld.com/Catalog/scoc01.htm < - cisco information

    http://munshi.sonoma.edu/s96/bus420/osilecture.html < - nice lecture
    information

  2. #2
    Banned
    Join Date
    Oct 2002
    Posts
    25

    Re: Networking Simplified - Part 05

    good info,fren... KEEP UP THE GOOD WORK....

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