3.5.5.2.2.3 Receiving a TXUSER_ENLISTMENT_MTAG_PREPAREREQ Message
When the resource manager receives a TXUSER_ENLISTMENT_MTAG_PREPAREREQ message, the resource manager MUST perform the following actions:
If the connection state is Active:
If the fSinglePhase field of the message is nonzero:
Set the connection state to Single-Phase Committing.
Send a Single-Phase Commit request to the higher-layer business logic.
Otherwise:
Set the connection state to Preparing For Transaction Commit.
Send a Prepare request to the higher-layer business logic.
Otherwise, the message MUST be processed as an invalid message as specified in section 3.1.6.