If all of the spoke-SDPs bound to a SAP at a slave PE are selected as standby, then this should be treated from a SAP OAM perspective in the same manner as a fault on the service: an SDP binding down or remote SAP down. That is, a fault should be indicated to the service manager. If SAP-specific OAM is enabled toward the CE, such as Ethernet Continuity Check Message (CCM), Ethernet Link Management Interface (E-LMI), or FR LMI, then this should result in the appropriate OAM message being sent on the SAP. This can enable the remote CE to avoid forwarding traffic toward a SAP that drops it.
Figure: Example of SAP OAM interaction with master-slave pseudowire redundancy shows an example for the case of Ethernet LMI.
