Response models

The synchronous request and response model is associated with IMS.

Synchronous request and response
In the synchronous request and response model, the entire transmission is returned to the IMS node synchronously.

After the IMS program has prepared the response data for the IBM® Integration Bus message flow, it inserts that data onto a queue. IBM Integration Bus uses Open Transaction Manager Access (OTMA) to communicate with the IMS program. OTMA helps to correlate the input to the IMS program with the output from the IMS program by using a transaction pipe (TPIPE). Therefore, multiple concurrent message flows that are calling the same transaction each receive the relevant response.

The diagram shows how OTMA is used to communication with IMS.

The TPIPE is created automatically. It is not necessary for the name of the TPIPE to be known to IBM Integration Bus because it uses a mode of operation known as sharable persistent sockets, whereby a TPIPE is created automatically for every TCP/IP connection.

The output of a transaction can contain multiple messages. The IMS program inserts then purges each message, as shown in the following diagram. (For multi-segment output, the IMS program inserts multiple messages without purging them.) If the IMS program inserts multiple messages in a single sync point, OTMA correlates all of those messages to the input message and returns them all to the message flow as a single transmission.

The diagram shows how OTMA handles transactions that contain multiple messages.