Saturday, November 14, 2009

The OSI Model

The Open Systems Interconnect (OSI) model is a concept model that makes understanding network connectivity and communications easy. It also serves to create standards for network devices and hardware. Discuss the benefits of the OSI model for the Network Administrator of today. What other network models exist and discuss why they are not as popular as the OSI  model. Finally list 2 devices (hardware, software, application or similar entity) that is implemented in each layer of the OSI model.
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7 comments:

  1. UnknownNovember 15, 2009 at 4:39 PM

    First Off

    The benefits of OSI

    1) OSI models help network administrators see how the entire network functions and what device functions at what level.

    2) OSI models simplify how networks operate by breaking them up into smaller pieces as shown in its 7 layers.

    3) Helps to make network design easier and leaves room for network expansion in terms of devices and protocols because the network would be designed using one common model.

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  2. UnknownNovember 15, 2009 at 4:50 PM

    There are 3 types of networks models

    1) The OSI - widely used as it can be applied to simply any network as it analyzes all the layers from physical to application levels

    2) The DOD or TCP / IP model - this model was designed by the department of defense for military and internet usage. It isnt widely used because it is more applicable for internet networking. It basically defines how information is communicated and neglects the physical and hardware layer. This model is said to be fluid and easy to implement but can be neglectful of security which is why it may not be as widely used as the OSI model.

    There is also another netowrk model designed by CISCO - the hierarchical model which simply has 3 layers ( Access layer, core layer and distribution layer )

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  3. UnknownNovember 19, 2009 at 1:41 AM

    I have been going through my lecturer notes, and I came across something that I’m not too certain of:

    Lecturer notes 2, page6, The Client-Server Relationship.
    "Typically no client computer shares resources with other clients or the server"

    Since I’ve known networked PCs (clients) they always share something with each other, whether it is a printer, files etc. I’ve personal shared music and application setup on a PC at work.
    So I’m wondering if someone can shed some light on this…

    Regards
    Satesh Babulal

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  4. Rod Lee SinghNovember 22, 2009 at 6:34 PM

    Satesh Concern:
    Maybe what it means is that clients do not share resources with each other, the resources are shared through or from the servers and each client have access to them. Basically the client computers communicate with the servers only, and not with other clients.

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  5. Rod Lee SinghNovember 22, 2009 at 7:02 PM

    Answer to the last part of the question which i noticed no one attempted:

    Devices used in each layer:
    Layer 7 - gateway, web browser, email service
    Layer 6 - gateway, network redirector
    Layer 5 - gateway
    Layer 4 - brouter, gateway, cable tester
    Layer 3 - router, switch
    Layer 2 - bridge, NIC
    Layer 1 - repeaters, hubs

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  6. KemuelNovember 30, 2009 at 10:17 PM

    I think Satesh is not looking at the word "TYPICAL". In a typical client-server environment clients do not share resources. What is the purpose in any case when you have one or more servers? Remember a client sharing a particular resource can be affected by downtime. Sharing of resources among clients is more common in a peer-to-peer setup. Resources can be files, databases, applications, devices etc.

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  7. UnknownDecember 9, 2009 at 5:19 PM

    what satesh is speaking about is um ... your basic server - client setup over windows xp and vista. there is no special server, a client system is set as a server and connected by a router or switch just as any SOHO network. The sharing he speaks of is just regular print sharing and also file sharing where on a network, you set a workgroup and then u share a folder. that folder is not only shared to the server, but to any other system connected to the network and as such it can be accessed. it may however be blocked by the user account user name and password but using a simple registry edit value to take ownership of the said shared folder will unlock its contents to the viewer. hope this clears up the problem because i am more aware of these types of netoworking.

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