The administrative state of STP at the VPLS level is controlled by the shutdown command.
When STP on the VPLS is administratively disabled, any BPDUs are forwarded transparently through the device. When STP on the VPLS is administratively enabled, but the administrative state of a SAP is down, BPDUs received on such a SAP are discarded.
— config>service>vpls service-id# stp
— no shutdown