The administrative state of STP within a SAP controls how BPDUs are transmitted and handled when received. The allowable states are:
SAP Admin Up
The default administrative state is up for STP on a SAP. BPDUs are handled in the normal STP manner on a SAP that is administratively up.
SAP Admin Down
An administratively down state allows a service provider to prevent a SAP from becoming operationally blocked. BPDUs will not originate out the SAP toward the customer.
If STP is enabled on VPLS level, but disabled on the SAP, received BPDUs are discarded. Discarding the incoming BPDUs allows STP to continue to operate within the VPLS service while ignoring the down SAP. The specified SAP will always be in an operationally forwarding state.
The administratively down state allows a loop to form within the VPLS.
— config>service>vpls>sap>stp#
— [no] shutdown
Range: shutdown or no shutdown
Default: no shutdown (SAP admin up)