Start Data Traffic (SDT)

When required by the transmission services profile in the session parameters, Start Data Traffic (SDT) is sent from the PLU to the SLU at the beginning of the session and within a session after successful sequence-number resynchronization has occurred. In both cases, SDT informs the SLU that the flow of data requests, data-flow-control requests, and responses can be started (or resumed).

For more information on SDT, see Controlling flow. For the role of SDT in various sequences, see Request and response exchanges for typical communication operations.