I've got two things here. First is STP topology change we see in our logs. Logs shows that it happens after 1 hour or 3 hours and sometimes after 5 hours. My show spanning tree detail result on my root bridge bridge often shows that it is from a port-channel that hooks up to our distribution switch where our access to other buildings and sites is connected to. Quite difficult to trace it as I have a hybrid of Cisco and HP equipment's with my core as 2 Cisco 3750 (stacked) and two Cisco Nexus N9K-C9372TX configured as vPC and L3 as well. Can someone enlighten me whether I should be alarmed or is this normal.
The second is I'm after recommendation on my root bridge selection. When we deployed our Cisco Nexus as our core switch/router I never remove the role of root bridge from the Cisco 3750. Got this configured on my 3750 and its the root bridge at the moment for all my switches (Cisco and HP)
spanning-tree mode mst
spanning-tree extend system-id
spanning-tree mst 0 priority 16384
Would it be recommended to change the root bridge to the Cisco Nexus N9K-C9372TX. If so do i have to change the priority of both Nexus to be the same and lower than the Cisco 3750 (16384) or do I have to configure different priority numbers for both ?
Any help or recommendation will be really appreciated. Attach herewith is a drawing of how things are setup at my core
