root bridge selecting

[capa]

I currently have a Cisco 3750 running as a routed switch. From that switch are seven other Cisco 3750s, 3 in one stack and 2 in another, and two single remotes. Also, connected to this are six Trendnet switches. The oldest of these Trendnet switches shows in Auvik going down and back up very often. Occasionally this will cause the switch to need rebooting. Through the syslogs on the Trendnet switch, the only info I get is it selects a new root bridge many times, it just switches between two Mac addresses. It has the highest setting for priority, but the core Cisco doesn't show in the config what its priority is set at, does this mean it was not set? If so, then what should be the process of setting it and will it cause any issues? I am currently in the process of revamping my network, and it seems at the moment it is fragile. I am working with another company for the reconfiguration but they don't work with Cisco or Trendnet. The most I can do is search for info and that is why I am here. My main problem is, it is a very slow process and I need a solution for this issue soon. I appreciate any info I can get.  TIA

[MHM Cisco World]

I need to see topology 

[capa]

I hope this helps. The switches in question are CAP_SWITCH_TWO (that is the routed Cisco) and EmbManager (that is the Trendnet).

[MHM Cisco World]

sorry I see your topology without full get issue here any change can make L2 Loop. 
sorry I can not help you in this case
sorry again 
MHM

[Flavio Miranda · Accepted solution]

Hi

 " It has the highest setting for priority, but the core Cisco doesn't show in the config what its priority is set at, does this mean it was not set? "

 Which STP are you running? Did you check with the command show spanning-tree <vlan number>

"if so, then what should be the process of setting it and will it cause any issues?"

spanning-tree vlan vlan-id root primary

If you change the parameter the topology will be recalculated and there will be impact.

[capa]

The root bridge priority on the routed switch 32769. Thank you for the info.