Preparing to define the topology of a CICSplex

Topology definitions enable you to establish logical associations of CICS® systems within your enterprise.

This means that you can combine one or more related CICS systems to form a CICSplex and, within each CICSplex, combine one or more subsets of the CICS systems to form CICS system groups.

Establishing a CICSplex

Start of changeA CICSplex is identified to CICSPlex® SM via the CICSplex definition view (CPLEXDEF in the end user interface). To access this from the WUI main menu, click Administration views-->CMAS configuration administration views-->CICSplex definition. Once a CICSplex exists, you can assign an unlimited number CICS systems and CICS system groups to it.End of change

The names of the CICS systems and CICS system groups associated with each CICSplex must be unique and must not exceed eight characters in length. The names can match any name that is not assigned by CICSPlex SM, such as VTAM® APPLIDs.

The JCL used to start the CICS systems within a CICSplex must include the EYUPARM parameters as described in the CICS Transaction Server for z/OS® Installation Guide manual.

Combining CICS systems and CICS system groups

Although you can define a CICS system to only one CICSplex, you can assign a CICS system to multiple CICS system groups within the CICSplex. You can also assign the CICS system group to any number of other CICS system groups.

If you do not plan on using workload management facilities, there are no restrictions on how you combine CICS systems and CICS system groups to form a CICSplex. For example, you might associate CICS systems by:

If you do plan to use workload management facilities, you need to be aware that each CICS region may act as one or more of the following:

requesting region
The CICS region in which the work request originates.
routing region
The CICS region in which the decision is taken on where the work will run.
target region
The CICS region where the request is actioned.

For dynamic transaction routing, the requesting region and the routing region are typically TORs, and the target region is typically an AOR.

For inbound DPL client requests, the requesting region and the routing region are typically TORs, and the target region is typically an AOR.

For EXEC CICS START commands associated with a terminal, the requesting region is typically an AOR, the routing region is typically a TOR, and the target region is typically an AOR.

For peer-to-peer DPL requests, the requesting region, routing region, and target region are typically AORs.

For enterprise bean invocations, the requesting region is the client code that invokes the enterprise bean, the routing region is typically a CICS listener region, and the target region is typically an AOR.

You must ensure that:

Components of a CICS system definition

When you define a CICS system to a CICSplex, you need to provide the following types of information:

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