Dynamic routing with CICSPlex SM

A transaction can be defined to CICS® as either local or remote. Local transactions always run in the requesting region; remote transactions can be routed to any CICS system connected to the routing region. Routing of remote transactions can be dynamic, static, or ATI-controlled.

When a remote transaction is initiated, the CICS relay program is invoked. The CICS relay program links to the dynamic routing program EYU9XLOP. EYU9XLOP creates the environment necessary for CICSPlex® SM-based dynamic routing and sets up the CICSPlex SM run-time environment. You must specify EYU9XLOP in the system initialization table (SIT) parameter.

Note:
If the target region is not going to be set up as a routing region, then EYU9XLOP should not be specified in the DTRPGM and DSTRPGM SIT parameters, because this will cause routed transactions to hang in EYU9XLOP waiting for the workload which will never come.

CICS notifies EYU9XLOP of all routing requests. These are:

When CICS links to EYU9XLOP, it passes the CICS communication area named DFHDYPDS to it.

Control then passes to the CICSPlex SM workload management facilities. CICSPlex SM initializes the workload management MAS agent code and engages its routing action process. This process is called internally if any of the following conditions are true:

The internal routing action process produces the same results as executing the assembler version of EYU9WRAM as it is distributed with CICSPlex SM. If no additional dynamic routing control is required at your enterprise, the internal process provides better performance.

The EYU9WRAM module (or its equivalent internal process) receives the CICSPlex SM-based communication area EYURWCOM. (An entry for EYU9WRAM is added to the CICS system definition file, DFHCSD, for each CICS system during installation.) As distributed with CICSPlex SM, EYU9WRAM drives CICSPlex SM workload management processing. EYU9WRAM does this by first obtaining the appropriate list of target region candidates based on the transaction group, and the terminal id, luname, user id, or process type. Then EYU9WRAM selects a target region from the list of candidates.

Related concepts
Workload management and dynamic routing
Workload requirements
Related tasks
Creating a user-replacement module for EYU9WRAM
Modifying dynamic routing
Related reference
CICS release requirements for dynamic routing
Sample source programs and copy books
CICSPlex SM data areas
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