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Cisco 3750 Stacking Issue

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  • Cisco 3750 Stacking Issue

    I recently bought an additional 3750 switch to stack with an existing 3750 switch. I was under the impression that I would be able to properly cable the switches together, power on the switch and I would be done.

    That wasn't the case. I am unable to view the new switch I added to the stack. I ran the 'show switch' command and here's my output.

    #sho switch
    Switch# Role Mac Address Priority State
    *1 Master xxxx.xxxx.xxxx 1 Ready
    2 Member yyyy.yyyy.yyyy 1 Version Mismatch

    I am not sure how to correct the version mismatch. I've been up and down on the net trying to find the solution, but so far I have been unable to.

    Any ideas would be appreciated.
    MCITP:SA, MCSA 2003, MCP, CCNA, A+, Net+, Security+

  • #2
    Re: Cisco 3750 Stacking Issue

    From Cisco
    Switches with different Cisco IOS software versions likely have different stack protocol versions. Switches with different major version numbers are incompatible and cannot exist in the same switch stack.

    3750-Stk# show switch
    Switch# Role Mac Address Priority State
    1 Member 0015.c6f5.6000 1 Version Mismatch
    *2 Master 0015.63f6.b700 15 Ready
    3 Member 0015.c6c1.3000 5 Ready

    Switches with the same major version number but with a different minor version number as the stack master are considered partially compatible. When connected to a switch stack, a partially compatible switch enters version-mismatch (VM) mode and cannot join the stack as a fully functional member. The software detects the mismatched software and tries to upgrade (or downgrade) the switch in VM mode with the switch stack image or with a tar file image from the switch stack flash memory. The software uses the automatic upgrade (auto-upgrade) and the automatic advise (auto-advise) features.

    The auto-upgrade occurs if the software release that runs on the stack master is compatible with the switch in VM mode and the tar file of the current image is available with any of the stack members. If tar file of the current image is not available, the auto-advise feature will recommend that a compatible image be downloaded with the required commands. The auto-upgrade and auto-advise features do not work if the switch master and switch in VM mode run different feature sets/packaging levels (IP services and IP base), but, from Cisco IOS Software Release 12.2(35)SE, auto-upgrade does support upgrades between cryptographic and non-cryptographic images of the same packaging level.

    Note: If the auto upgrade does not work on the switch that shows the version mismatch error, use TFTP to manually upgrade the switch.

    Wow, first response time almost within a hour
    Last edited by Dumber; 5th March 2008, 21:00.
    Technical Consultant

    "No matter how secure, there is always the human factor."

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    • #3
      Re: Cisco 3750 Stacking Issue

      I checked that article out during my initial research, but my switches did not perform the auto-upgrade for some reason. I rebooted the new switch several times.

      I finally had to log onto the first switch and issue the command:

      archive copy-sw /overwrite /destination-system 2 1

      Where the 2 represents the new switch and the 1 represents the old switch.

      After the command completed, I issued a reload slot 2.

      This command basically uploaded the image file from the old switch to the new switch and deleted the old image on the new switch. It's basically the manual vesion of the auto-upgrade.

      Thanks for the help Dumber.
      MCITP:SA, MCSA 2003, MCP, CCNA, A+, Net+, Security+