CICS® multiregion operation (MRO) enables CICS regions that are running
in the same MVS™ image, or in the same MVS sysplex, to communicate with each
other. MRO does not support communication between a CICS system and a non-CICS
system such as IMS™. 2
ACF/VTAM and SNA networking facilities are not required for MRO. The support
within CICS that enables region-to-region communication is called interregion communication (IRC). IRC can be implemented in three ways:
- Through support in CICS terminal control management modules and by use
of a CICS-supplied interregion program, DFHIRP, loaded in the MVS link pack
area. DFHIRP is invoked by a type 3 supervisory
call (SVC).
- By MVS cross-memory services, which you can select as an alternative to
the CICS type 3 SVC mechanism. Here, DFHIRP is used only to open and close
the interregion links.
- By the cross-system coupling facility (XCF) of MVS. XCF is required for
MRO links between CICS regions in different MVS images of an MVS sysplex.
It is selected dynamically by CICS for such links, if available.
This topic describes the communication part of MRO. Multiregion operation (MRO) gives a brief description of multiregion operation.
The external CICS interface (EXCI) uses a specialized
form of MRO link to support: communication between MVS batch programs
and CICS; DCE remote procedure calls to CICS programs.
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