RED CICS Triggers

CICS RED provides a server module that user application can link to the called SXCOTRED which provides an immediate synchronous method.

SXCOTRED is a reentrant THREADSAFE and OPENAPI, and accessible by multiple transactions concurrent without locking issues. SXCOTRED runs on an L8/L9 TCB and receives parameters from the user application having to do with the following items:

  • Message location
  • Message size
  • RED Trigger service definition in Substation ES on how to handle message feedback
The flow is listed as follows:
  1. User application sets up message data in the following items:
    1. A Container (Single or Multiple)
    2. A storage location
    3. CICS DFHCOMMAREA
  2. User application sets up the SXCOTRED parameter information.
    1. The Services ID to use (Substation ES RED Trigger definition)
    2. Type of data (Container, Storage Location or DFHCOMMAREA)
    3. Type of Response (Container, TSQ, CommArea, Data location)
    4. Timeout value
  3. User application does CICS LINK to SXCOTRED.
  4. SXCOTRED sends the message immediately to Substation ES. If no Substation ES is available, an error is immediately generated and returned to caller.
    1. The Substation ES accepts the message, and then sends it to its destination based on the Service definition it has.
      • "RELIABLE" messages are considered delivered when a Substation ES accepts the message. This type of message is the most efficient but may get dropped it there is a problem delivering the message to the end destination.
      • "GUARANTEED" messages are considered delivered when a Substation ES delivers the message to its defined destination. Anything other than a confirmed delivery to its defined destination results in an immediate error which is returned to the calling program.
      • "ORDERED" is the same a "GUARANTEED"
    2. If Substation ES fails, SXCOTRED returns an error condition to the caller.
  5. User application reviews a return code and a reason code for any error indication.
  6. If no errors, the response data is present as indicated by the parameters.
  7. The user application can link to SXCOTRED multiple times under the same Unit-Of-Work which forwards the message to the Substation ES. There is no special processing for user application that abends, or issues a ROLLBACK. Once the call to SXCOTRED is done, the RED message process is committed and there is no back out process.
  8. When the user application ends, a last link to SXCOTRED is made to terminate the connection with the Substation ES.

This method is useful for Processes that need immediate data publishing of many messages to the ESB environment such as Credit Card updates, EDI processes, and so on.