An ingress multi-protocol label switching (MPLS) label switched router (LSR) forwards a set of packets associated with a first set of forwarding equivalence classes (FECs) along a label switched path (LSP) to an egress MPLS LSR. Logic in the ingress MPLS LSR produces an operation and maintenance (OAM) connectivity verification probe message encoding the first set of FECs, and forwards the OAM connectivity verification probe message along the LSP to the egress MPLS LSR. Logic in the egress MPLS LSR produces an encoding of a second set of FECs. Logic in the egress MPLS LSR compares the encoding of the first set of FECs in the connectivity verification probe message to the encoding of the second set of FECs, and produces an indication if the comparison indicates that the first set of FECs is not a subset of the second set of FECs.