When a VPLS service is down:
If the service is not a B-VPLS service, the SMGR propagates the fault to OAM components on all SAP and SDP-bindings in the service.
If the service is a B-VPLS service, the SMGR propagates the fault to OAM components on all SAP and SDP-bindings in the service as well as all pipe services that are associated with the B-VPLS instance.