binding
conflict
lease
The 48 bit (6-byte) MAC address of a switch is used in conjunction with the bridge priority value and the system ID extension as criteria for the root bridge election. If the bridge priority value and the system ID extension are identical on two or more switches, the lowest 48-bit MAC address is then used as a tie breaker. These values together make up the cohesive Bridge Identifier used to elect the root bridge. The following Wireshark packet capture of a BPDU illustrates these values. The bridge priority and system ID extension are the 16-bit hexadecimal value 80 01 (to the left of the MAC address) below representing the bridge priority value of 32768 and a system ID extension of 1 (VLAN 1).