The value of tmnxOtuIfSmTtiTxMode specifies the type of Trail Trace
Identifier (TTI) for the Payload Structure Identifier (PSI) in
the OTU overhead.
Specifying a tmnxOtuIfPsiTtiTxMode value of 'auto (0)' along with
tmnxOtuIfPsiTtiTx set with a single octet of '0xFF' will revert the
PSI-TTI to the default:
'<system-name>/<iom-slot>/<mda-slot>/<port-number>/C<dwdm-channel>'