This is the pseudowire ID that this switching node embeds in the SP-PE TLV when forwarding aggregated fault information onward to the next segment of a multi-segment pseudowire, identifying which PW segment the outgoing fault notification is being reported against. This is the mirror image of cienaCesMplsPwIdInRemoteFault -- one describes what was received, this describes what's being sent onward -- and together they let an admin trace fault propagation in both directions through an MS-PW chain. Comparing the PW ID sent here against what the next-hop node actually receives, via its own IdInRemoteFault object, is how an admin verifies the fault-propagation chain is correctly linked end to end.