3.8.5.1.2.1.6 Receiving a PARTNERTM_PROPAGATE_MTAG_PHASE0 Message
When the Subordinate Transaction Manager Facet (section 1.3.3.3.5) receives a PARTNERTM_PROPAGATE_MTAG_PHASE0 message, the Subordinate Transaction Manager Facet MUST perform the following actions:
If the connection state is Awaiting Phase Zero:
Set the connection state to Awaiting Phase Zero Outcome.
Signal the Begin Phase Zero event on the Core Transaction Manager Facet with the transaction object referenced by the Enlistment object referenced by this connection.
Otherwise, the message MUST be processed as an invalid message as specified in section 3.1.6.