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
