Asynchronous callout request

Asynchronous callout requests do not require the IMS application program that issues the request to wait for a response in the dependent region. Upon issuing an asynchronous callout request, the application program can terminate and free the dependent region. Any response to the callout request that is returned to IMS is treated as a new incoming transaction and IMS schedules a new application program instance to process it.

If an asynchronous callout request generates a response, however, the benefit gained by freeing dependent regions might be offset by the additional complexity of managing the response. For asynchronous callout responses, your installation is responsible for developing the method for correlating the response to the original request. For synchronous callout requests, IMS manages correlation for you.

IMS provides various sample application programs to test callout support. For more information, see Samples for the callout function.