To fix frequent STP topology changes, you should start by using the 'show spanning-tree' command to identify any problematic ports. Then, check the physical connections to ensure there are no faults and that everything is stable. I've already checked and confirmed that “spanning-tree portfast edge” and “spanning-tree bpduguard enable” are configured on all access switches. Has anyone dealt with this issue. Hello, recently we have recieved some topology change messages on our core switch (5900 IRF stack, stp. Logbuffer: MSTP/6/MSTP_NOTIFIED_TC: Instance 0's port Bridge-Aggregation1. The switches are connected through fiber cables. We found one switch having multiple. The issue isn't causing any major disruptions, but it is concerning. RSTP runs on switches by default, and we do not explicitly configure the core switch as the root bridge for all VLAN as we think. I am working with support on an issue where randomly we have a network interruption that looks like it's caused by some aggregate ports on our MS425 going down and back up and causing spanning tree topology change. Anyway, looking in the event log I see this a.
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