The value of tmnxOtuIfPsiTtiTx specifies the Trail Trace Identifier
(TTI) for the Payload Structure Identifier (PSI) in the OTU overhead.
This identifier can be a string or a non-printable sequence of bytes.
Specifying a one octet string with the value '0xFF' along with
a tmnxOtuIfPsiTtiTxMode set to the value of 'auto (0)' will reset
the PSI Trace to the system generated value.