Modules
Figure 1 gives an overview
of the modules involved with interregion communication. Figure 1. Interregion communication

The modules for IRC are of two types:
- The interregion communication program: DFHIRP.
- CICS® address space modules: DFHCRC (interregion ESTAE exit), DFHCRNP (CICS interregion connection manager), DFHCRR (interregion session recovery), DFHCRSP (CICS interregion communication startup module), DFHZCP (CICS terminal management program), and DFHZCX (which includes DFHZIS2, the interregion service subroutines).