Introduction to function shipping

CICS® function shipping enables CICS application programs to use EXEC CICS commands to:

An illustration of a shipped file control request is given in Figure 2. In this figure, a transaction running in a CICS system, CICA, issues a file control READ command against a file called NAMES. From the resource definition table, CICA discovers that this file is owned by a remote CICS system called CICB. CICA changes the READ request into a suitable transmission format, and then ships it to CICB for execution.

In CICB, the request is passed to a special transaction known as the mirror transaction. The mirror transaction recreates the original request, issues it on CICB, and returns the acquired data to CICA.

Figure 2. Function shipping
 The picture shows two connected CICS systems, CICA and CICB. On CICA, the definition of a file called "NAMES" specifies REMOTESYSTEM(CICB). On CICB, "NAMES" is defined as a local file. A program on CICA issues an EXEC CICS READ FILE(NAMES) command. CICA sees that "NAMES" is owned by CICB and ships the request to CICB. In CICB, the mirror transaction is attached. The mirror issues the READ command against "NAMES" and passes the retrieved data back to the program on CICA.

Related concepts
Transparency to application
Remote resources that can be accessed
How function shipping works
Synchronization
Function shipping examples
Related reference
CICS product communication support
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