Endpoint X is operationally up if at least one of its objects is operationally Up. It is Down if all its objects are operationally down.
If the SAP in endpoint X transitions locally to the down state, or received a SAP Down notification via SAP-specific OAM signal (SAP MEP), the node must send T-LDP SAP down status bits on the Y endpoint ICB spoke-SDP only. BGP-MH SAPs support MEPs for ifStatusTLV signaling. All other SAP types cannot exist on the same endpoint as an ICB spoke-SDP because non Ethernet SAP cannot be part of an MC-LAG instance or a BGP-MH Instance.
If the ICB spoke-SDP in endpoint X transitions locally to Down state, the node must send T-LDP SDP-binding down status bits on this spoke-SDP.
If the ICB spoke-SDP in endpoint X received T-LDP SDP-binding down status bits or PW not forwarding status bits, the node saves this status and takes no further action. The saved status is used for selecting the active transmit endpoint object as per Pseudowire Redundancy procedures.
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, including the ICB:
transitioned locally to the down state because of the operator or BGP-MH DF election
received a SAP down notification via remote T-LDP status bits or via SAP-specific OAM signal (SAP MEP)
received status bits of SDP-binding down
received status 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, including the ICB spoke-SDP, performed any or all of the following operations, the node saves this status and takes no further action:
received T-LDP SAP down status bits
received T-LDP SDP-binding down status bits
received PW not forwarding status bits
The saved status is used for selecting the active transmit endpoint object as per Pseudowire Redundancy procedures.
If all objects in endpoint Y, except the ICB spoke-SDP, performed any or all of the following operations, the node must send status bits of SDP-binding down over the X endpoint ICB spoke-SDP only:
transitioned locally to the down state
received T-LDP SAP down status bits
received T-LDP SDP-binding down status bits
received PW not forwarding status bits
If all objects in endpoint Y performed any or all of the following operations, the node must send status bits of SDP-binding down over the X endpoint ICB spoke-SDP only, and must send a SAP down notification on the X endpoint SAP via the SAP-specific OAM signal:
transitioned locally to down state
received T- LDP SAP down status bits
received T-LDP SDP-binding down status bits
received PW not forwarding status bits
In this case the SAP MEP ifStatusTLV is operationally down and also signals the BGP-MH site, if this SAP is part of a BGP Site.