4.1.3.1.2 Phase One

In the first phase of two-phase commit processing, the TIP superior transaction manager sends the PREPARE TIP command to the TIP subordinate transaction manager.

When the TIP subordinate transaction manager receives the PREPARE TIP command, it iterates through each of the transaction's subordinate branches and notifies the subordinates that the transaction processing has begun. The TIP subordinate transaction manager waits for reply notifications from each of its subordinates in order to determine the outcome of the transaction.

If each subordinate branch of a transaction successfully prepares for the transaction, the TIP subordinate transaction manager responds to the TIP superior transaction manager with the PREPARED TIP command. The State of the TIP connection changes to Prepared.