Every switch has a Bridge ID that uniquely identifies it in STP. The Bridge ID is bytes: bytes of priority and bytes of MAC address. The default priority is . When comparing Bridge IDs, lower is better. Priority is compared first. If priorities tie, the lower MAC address wins. You can manually lower a switch's priority to force it to become root. Just set the priority to or , and that switch will almost always win the election.
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$ curl repovive.com/roadmaps/network-design/spanning-tree-and-link-aggregation/bridge-id-structure
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