Defect is defined as interruption of the capability of a transport entity (e.g., network connection) to transfer user or OAM information. There are six types of defect: 0: no defect; 1: dServer; 2: dPeerMe; 3: dLOCV, Loss of Connectivity Verification defect; 4: dTTSIMismatch, Trail Termination Source Identifier Mismatch defect; 5: dTTSIMismerge, Trail Termination Source Identifier Mismerge defect; 6: dExcess, Receiving excess rate of CV/FFD; 7: dUnknown, Unknown defect in the MPLS network.. 8: dOamFail, AutoProtocal timer expires. 9: dIngressDown.