Howto: Stack 3750g 12s with 3750g 48T?

Discussion in 'Cisco' started by Johannes, Mar 24, 2010.

  1. Johannes

    Johannes Guest


    we bought a new core switch (3750G with 48 gig Ethernet Ports) and
    wanted to stack it with our old fibre optic 3750g 12s switch.
    First we ran into "unsupported Firmware" trouble, after a copy from
    old to new, they have same FW.
    But now the Master switch tells somthing about "SDM missmatch".
    After reading a lot of Cisco documentation i am not sure, what to

    On the old 3750g 12s the default aggregation template is activated. Do
    i have to change this to desktop template?

    And if yes, why?

    Thank you in advance

    Johannes, Mar 24, 2010
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  2. Johannes

    Thrill5 Guest

    In general this is what you need to do....

    Unstack both switches and reboot them.
    Make sure both switches are booting the SAME IOS binary file. If they are
    different versions it won't work.
    Save a copy of the both switches configurations on your PC (if you need to
    keep the configuration)
    Do a write erase on both switches.
    Power them both off.
    Stack them
    Power them both on (if you have a preference for which one you want as
    Master, power that one on first wait a few minutes and then power on the
    other one.)

    Paste the configuration of one of switches and ONLY the interface
    configurations from the other. You may have to do a bit of editing of the
    interface names because they might change (The master will be 1/0/x and the
    other will be 2/0/x where before it was also 1/0/x).
    Thrill5, Mar 24, 2010
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  3. Johannes

    Johannes Guest


    as far as I read the articles on Ciscos website, it seems, that the
    3750 12s has a bit more Memory, and default is the SDM agreggation
    which is not supported by the 3750 48T.

    So I only see 2 solutions
    1. We set the 3750 48T as Stack Master and he tells the other 3750 12s
    to switch to routing desktop template and reboot all other switches
    2. We set the routing desktop template manualy on the actual Stack
    master 3750 and reboot all other switches

    Is that right?

    Johannes, Mar 25, 2010
  4. Johannes

    Johannes Guest

    Hello Peter,

    Thank you for your help.

    Today at 5am we scheduled a downtime for 15 minutes, and i linked the
    switches with Stack cables.
    Than i configured the master 3750 12s (with 8gbic modules) for usind
    "default desktop template" (#sdm prefer default desktop).
    After a reload, he submited this to the member switches and everything
    was fine, no more errors or missmatches.

    The problem is an incompatibility of the memory usage templates,
    because the "out of the box" settings of a 3750 12s is "aggregation
    this kind of setting is not available on 3750 48t.
    Now, after switching to "default desktop template" the sdm matches on
    all switches.

    Johannes, Mar 26, 2010
  5. Johannes

    colin Guest

    hi johannes,

    i'm currently having the same problem.
    as cisco's papers describe only WS-C3750-12S have got the ability to set sdm
    to an aggregate template.

    Even doe Cisco says in their product specs that within a Series there are no
    hardware differencialitys, for some reason the WS-C3750-12-S is kind of

    The 12-S is the only one capable of aggregate template. in order to stack
    a -12-S with other 3750 types, as you have done so, one needs to downgrade
    to an desktop sdm.
    I haven't seen it possible on any other WS-C35XX or WS-C37XX platform so

    As i've read, the new WS-X3750 haven't got an aggregeat template...

    if some one of Cisco would be as kind in order to tell us what kind of
    alternatives there are in order to address this problem, i realy would
    appreatiate this.

    colin, Mar 30, 2010
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