It is not possible to configure standby-signaling-slave on endpoints or spoke-SDPs that are bound to an IES, VPRN, ICB, or MC-EP, or that are part of an MC-LAG or MC-APS.
If standby-signaling-slave is configured on a specific spoke-SDP or explicit endpoint, then the following rules apply. The rules describe the case of several spoke-SDPs in an explicit endpoint. The same rules apply to the case of a single spoke-SDP outside of an endpoint where no endpoint exists:
Rule for processing endpoint SAP active/standby status bits:
Because the SAP in endpoint X is never a part of an MC-LAG/MC-APS instance, a forwarding status of active is always advertised.
Rules for processing and merging local and received endpoint objects with an up or down operational status:
Endpoint X is operationally up if at least one of its objects is operationally up. It is Down if all of its objects are operationally down.
If all objects in endpoint X performed any or all of the following operations, the node must send status bits of SAP down over all Y endpoint spoke-SDPs:
transitioned locally to down state
received a SAP down notification via remote T-LDP or via SAP-specific OAM signal
received status bits of SDP-binding down
received states bits of PW not forwarding
Endpoint Y is operationally up if at least one of its objects is operationally up. It is down if all its objects are operationally down.
If a spoke-SDP in endpoint Y, including the ICB spoke-SDP, transitions locally to down state, the node must send T-LDP SDP-binding down status bits on this spoke-SDP.
If a spoke-SDP in endpoint Y received T-LDP SAP down status bits, and, or T-LDP SDP-binding down status bits, and, or status bits of PW not forwarding, the node saves this status and takes no further action. The saved status is used for selecting the active transmit endpoint object.
If all objects in endpoint Y, or a single spoke-SDP that exists outside of an endpoint (and no endpoint exists), the node must send a SAP down notification on the X endpoint SAP via the SAP-specific OAM signal, if applicable:
transitioned locally to down state
received status bits of T-LDP SAP down
received status bits of T-LDP SDP-binding down
received status bits of PW not forwarding
received status bits of PW FWD standby
If the peer PE for a specified object in endpoint Y signals PW FWD standby, the spoke-SDP must be blocked in the transmit direction and the spoke-SDP is not eligible for selection by the active transmit selection rules.
If the peer PE for a specified object in endpoint Y does not signal PW FWD standby, then spoke-SDP is eligible for selection.