network design confusions

Discussion in 'CCENT / CCNA' started by shivaji, Jun 25, 2022.

  1. shivaji

    shivaji Bit Poster

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    Provide IT infrastructure details for a government school with 4 departments including ISP department which are around 500 meters apart from each other. Three departments have 5 labs each with around 24 computers in each room. ISP contains server farm with server like DNS, DHCP, E-mail, FTP and webserver and the main interet router which will be connected to the upstream provider. Propose appropriate equipment (L1,L2 and L3) and physical wires for the network design.


    Solution-:




    1)

    D1=24*5=120

    D2=120

    D3=120

    ISP 5 hosts


    2) Components required-:


    a) One main router and other routers for each department and ISP.

    b) servers

    c) Optical fibre to connect between 2 departments and ISPs.

    d) CAT 6 cable to connect to internet in hosts.

    e) Wireless access point to use wifi in laptop.

    f) laptop/pcs

    g) switch (why do we need switch when there is router in every step in this case? I don’t see a point of using the switch)



    3) Subnetting network design, logical network design-:


    Assume IP address be 192.168.0.0/23


    [​IMG]


    4) Physical network design(non redundant)


    I tried visio and other network diagramming softwares, I could not do justice there, so I redraw the network multiple times and made this ok diagram. Hope you understand it.

    [​IMG]

    Questions-:


    1) How will we make this network redundant? Will the below figure work(that solution?)


    2) What are L1,L2 and L3 components in this? Probably it’s asking core, distribution and access layer. My guess


    main router is core(I don’t think it’s as it is just the ISP),


    Secondary routers and switches are distribution layer components


    Hosts are access layer components.


    This topic surprisingly has no similar questions answered anywhere else although the subnetting part of this is fairly common thing in many examinations. I would love to spend my whole life reading top down network design but unfortunately my course doesn’t allow me to do so.


    A similar question answered here in this book-:


    [​IMG]


    [​IMG]


    [​IMG]

    [​IMG]

    [​IMG]
     
  2. FlashDangerpants

    FlashDangerpants Byte Poster

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    Call me old school, but I would never try subnetting 192.168.x.x with /23, even if the network gear allows it I would expect client systems to complain.

    When asking l1 l2 and l3 components, I think they want you to specify the L1 cabling (at 500m that's not UTP so you want fibre), the L2 switching gear and which L3 routers to use. I imagine they want them all to be Huawei.

    They are sparing you the core, dist, edge issue by placing the core network remotely. the core is where all of your real servers and data live. For this thing you only have dispersed departmental servers.

    For redundancy, that all depends on whether your course includes OSPF or any other routing protocol, even RIPv2 if that's all they got. If it does, you can buy 4 extra fibre cables, 8 fibre inserts to fit them, and link D1 to D2, D2 to D3, D3 to D4 and let OSPF handle it if the fiber connecting D1 to Main router gets cut.

    Normally in this design the Main router would be an actual router with about 4 interfaces totoal. D1, D2 etc woul usually be Layer 3 routing switches. I think that is probably reading ahead to a future class though, and in your current class they should already have told you what they want from tyou here.
     
    Certifications: MCITP Exchange 2010, MCSA Svr 2012
    WIP: Exchange 2013

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