This read-only value is an 8-byte hexadecimal identifier of the spanning-tree root bridge, combining the bridge priority (first two bytes) with the address of the adapter that connects to the LAN segment with the lowest segment number. An administrator reads this to confirm which unit in the bridged network currently holds the topological top position, since the root bridge has the lowest bridge identifier of all units. For example, after adding a new switch with a lower configured priority, an administrator would poll statBridgeBridgeDesignatedRoot on the other units to verify they all converged on the new device as root.