Recovering outstanding message traffic after a failure

A CICS®-IMS session can fail or terminate in any of several situations.

The situations in which a CICS-IMS session can fail or terminate include:
  • A communication component (for example, VTAM® or NCP) fails.
  • The CICS or IMS subsystem fails.
  • A direct VTAM or subsystem command (for example, an IMS /CLSDST or /STOP command) is entered.
  • The CICS transaction or IMS transaction fails (indirectly as a result of subsequent error processing).

In each of these situations, the session failure appears similar to the remaining operative subsystems. However, the resulting recovery and resynchronization processes you must follow differ. This topic describes what happens in the event of a communication component failure, an IMS or CICS subsystem failure, or the issuing of a direct command against the session between the two subsystems.