Cisco hierarchy question

Discussion in 'Cisco' started by smokejo, Nov 23, 2006.

  1. smokejo

    smokejo Guest

    Hi

    I'm trying to visualise the Cisco hierarchy of
    access-distribution-core.

    So far, I understand that the access layer is where the users are
    connected to (e.g. 2960 switches), the distribution is where ACLS's,
    VLAN routing etc takes places (e.g 3750 switches) and the core layer is
    simply for fast thoroughput of data (e.g. Cisco 5000 switch).

    As below;

    5000
    3750 3750
    I I I I
    2960-2960-2960-2960

    What I don't understand then is why do Core switches such as the 4000.
    5000, and 6000 Cat switches have so many ports? Surely it should be the
    access layer switches with most ports, then the distribution and
    finally the core with the least (as in the diagram above, since the
    core switch there only connects the two 3750's together).

    To help me, I've built a little home lab with three 2950 switches, a
    2620 router (intervlan routing), and an old 5000 switch. Would the
    optimum method be for all to be connected to the 5000 switches ports,
    as below

    5000
    2950 2950 2950 2620

    or should it be

    5000
    2620
    2950 2950 2950

    Very confused, and could appreciate some advise from others!

    Thanks!
     
    smokejo, Nov 23, 2006
    #1
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  2. smokejo

    Guest Guest

    when a network requires the core dist access layout it is because they
    have many users, probably 1000's and more, so when they have a big cat
    switch at the core, all of those ports will be trunking to another
    switch(dist), or they will bundle many ports together through
    etherchannel to proivde enough bandwidth, and all those ports on the
    dist switch trunk to smaller switches which users plug into, that gives
    an idea on the bandwidth and speed the core switches need.. i
    understand you are just testing it, but with 5 switches you wouldn't
    use a 3 tier layout like this.

    Flamer.
     
    Guest, Nov 23, 2006
    #2
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  3. smokejo

    smokejo Guest

    Thanks for the replies.

    Just one final question, in my home lab of the 2950's, 2620 (intervlan
    routing) and 5000 switch, what would be the most effecient setup?

    Thanks again.
     
    smokejo, Nov 24, 2006
    #3
  4. smokejo

    smokejo Guest

    Thanks....out of curiosity, if I had a bunch of 2950's and a layer 3
    switch, such as a 3550 (but with no spare gigabit ports), where should
    the server block be connected? To the 2950's, the 3550, or does it not
    matter?
     
    smokejo, Nov 25, 2006
    #4
  5. smokejo

    Merv Guest

    Lets assume your setup is emulating a business network and that the
    3550 is located in a central location ( computer room?). For this type
    of setup one would connect the server to the 3550 because usually the
    computer room would be air-conditioned and access closet are gnerallly
    not.

    This topology would also result in users being equidistant from the
    server in terms of the number of switch hops.
     
    Merv, Nov 25, 2006
    #5
  6. smokejo

    smokejo Guest

    Thanks guys....
     
    smokejo, Nov 25, 2006
    #6
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