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 7450 ESS, 7750 SR, or 7950 XRS. When STP on the VPLS is administratively enabled, but the administrative state of a SAP or spoke-SDP is down, BPDUs received on such a SAP or spoke-SDP are discarded.
CLI syntax:
config>service>vpls service-id# stp
no shutdown