CICS request exit
A CICS® request exit program can be called by CICS Transaction Gateway at run time to dynamically select a CICS server.
A CICS request exit typically decides which CICS server to select from the CICS server name, user ID, and transaction ID passed with the request.
If the CICS request exit does not specify the name of a CICS server, CICS Transaction Gateway uses the default CICS server, if one has been defined.
If the CICS request exit does not specify a CICS server name and a default CICS server has not been defined, CICS Transaction Gateway assumes that the EXCI protocol is being used, and delegates the decision about which CICS server to use, to EXCI. The EXCI interface can then optionally use DFHXCURM to select a target CICS server.
If a retryable error occurs and the retry limit has not been reached, CICS Transaction Gateway calls the CICS request exit again. If the retry count limit has been reached, CICS Transaction Gateway returns the error that occurred on the last retry.