High Rate of STP Topology Changes

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High Rate of STP Topology Changes

I get "High Rate of STP Topology Changes" on all of my Meraki Core switchports that are connected to other non-Meraki switches. Should I be concerned and what would be my next steps in troubleshooting this? 

Head in the Cloud

I'd, first of all, understand your STP topology and then work backwards from there. Do you have the Layer 2/STP topology diagramed/documented at all?
Eliot F | Simplifying IT with Cloud Solutions
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Agreed, I'd confirm all of the physical connectivity and do some quick packet captures or work with Support to find the source(s) of the TCN BPDUs and start from there, possibly even temporarily admin-downing certain redundant/blocking links to isolate the issue.

I'm having the same issue on my Meraki. It only has one uplink to the Cisco core switch. None of my other Meraki switches are having the same issue. I'm fairly new to Meraki, so any help is much appreciated.

Kind of a big deal

Have you configured the root priority for the switch that should be the core of your network?



Next the other switches, what are they?  If they are Cisco Enterprise switches I would configure them to use mst "spanning-tree mode mst".

If they are dumb layer 2 switches it is possible they don't even run spanning tree.


Look for links between edge/leaf switches that should be there.  You ideally want a loop free design where the downstream switches only connect to the core switch and no other switches.

Building a reputation

Also, in addition to the above....I found in a couple of my networks I had that error on my Meraki Core switch another tech had ports configured incorrectly, mismatches, and in fixing that removed my errors.
Kind of a big deal

Also make sure every single access port (connecting end devices) on your switches in your entire network is running in portfast/edge mode.
If you don't every time a device turns off or on you will get a TCN flood in your network causing shortened MAC address lifetimes.

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