Indicia are provided to a client of Out-of-Frame errors and message bit parity errors that occur during the transmission of a message through a network, wherein the message includes the client data multiplexed with other data and formatted into a message that includes a plurality of transport overhead bytes. The transport overhead bytes of the multiplexed can include both defined bytes and undefined bytes. Predetermined bytes in the transport overhead may be used to store indicia of errors that are detected during the message transmission. These predetermined bytes are read by the client at the egress of the network. The transport overhead may contain both a section overhead portion and a line overhead portion and the predetermined bytes may be encoded in either a subset of the section or line overhead bytes. In addition, the indicia of errors may be encoded in an undefined portion of the section or line overhead. Alternatively, a portion of the section or line overhead that is defined may be redefined and used to store the encoded error indicia