Reliable

The following figure shows the message flow for the reliable communication service level:

For the execution of IMS transactions in reliable mode (send-then-commit, known as Commit Mode 1), the following rules apply:

• IBM Resource Recovery Service (RRS) is not required to complete a request with Substation ES.
• Transaction pipes need not be synchronized.
• The synchronization level is specified as None in the OTMA message prefix.
• Message receipt from IMS by Substation ES IMS Interface is in random order because XCF does not guarantee ordering.