The operational state of the Flex PW port is determined by the ability of the stitching service (that is, the Epipe that ties the PW port to the tunnel using L2oGRE spoke-SDP) to forward traffic. This relationship can cause the stitching service’s operational status to transition to a down state in the following cases:
the SDP far-end is not reachable
the route-table entry is missing
SDP is down
the Epipe service is administratively or operationally down