A method for detecting a mismatch between a first port and a second port includes determining whether a destination address associated with the second port and a virtual local access network identifier (VID) for a service instance monitored by a first maintenance end point are included in a table of the first port. The method further includes setting a traffic field in a first continuity check message. The method additionally includes receiving, at the first maintenance end point, a second continuity check message that includes a traffic field. The method also includes detecting a mismatch when the value of the traffic field in the second continuity check message does not match the value of the traffic field in the first continuity check message.