Spanning Tree Mismatch Detection

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Sep 15th, 2010
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Hi Guys,

I have a campus network (mix of 6513s and 2960/3750s) running with MST. In this setup, is there any CLI avbl to identfiy spanning tree config mismatch ?

Any hint/suggestion would be of great help.



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Peter Paluch Wed, 09/15/2010 - 12:13
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You can use the following commands:

  • show spanning-tree summary  - this will show you a summary info about your STP configuration including the version of MSTP you are running (IEEE 802.1D, RSTP, MSTP)
  • show spanning-tree - here you can see whether any port is marked as Bound - Boundary port - that would suggest that your MSTP configuration is different from the neighboring switch, or that the neighboring switch does not run MSTP but a different STP variant
  • show spanning-tree inconsistentports - on region boundaries, often a boundary port gets blocked by failed PVST+ Simulation mechanism. This command will display such ports, again suggesting that your MSTP configuration differs from the configuration of the neighboring switch

Please note that all recent IOS versions for the Catalyst series you have indicated support VTPv3 which is able to synchronize the MSTP configuration across a VTP domain. All changes made to the MSTP configuration on a VTP primary server switch will be automatically distributed to all other switches in the VTP domain. This will minimize configuration mistakes and prevent you from having different MSTP configurations on your switches.

Best regards,



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