BPDUs are exchanged between switches and the analysis of the Bridge ID and
Root ID information from those BPDUs determines which bridge is selected as the
root bridge.
In the example shown, both switches have the same priority
for the same VLAN. The switch with the lowest MAC address will, therefore, be
elected root bridge. In the example, switch X is the root bridge with a bridge
ID of 0x8401:0c0011111111.
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