Other CICS functions and components that facilitate a Parallel Sysplex

CICSPlex SM

CICSPlex® SM enables you to manage multiple CICS systems across multiple images from a single control point, as a single-system image (SSI). Just as CICSPlex SM can manage multiple CICS regions in a single z/OS® image, it can manage CICS regions across one or more Parallel Sysplexes. The provision of a single-system image enables you to operate at the logical rather than the physical level, without regard to either the scale or location of CICS resources.

CICSPlex SM workload management can dynamically route transactions and programs to the CICS region that is the most appropriate at the time, taking into account any transaction affinities and workload separation definitions that exist.

For more information about CICSPlex SM workload management, see Managing workloads.

CICS Intercommunication

CICS intercommunication is communication between a local CICS system and a remote system, which might or might not be another CICS system. There are two types of intercommunication; multiregion operation and intersystem communication:

Multiregion operations

By using CICS multiregion operation (MRO), CICS systems that are running in the same z/OS image, or in the same z/OS sysplex, can communicate with each other. MRO does not support communication between a CICS system and a non-CICS system, such as IMS. MRO does not need networking facilities.

Intersystem communication

CICS provides intercommunications facilities for intersystem communication over SNA (ISC over SNA) and IP interconnectivity (IPIC), so that you can communicate with external systems.

• CICS provides intersystem communication over a TCP/IP network. This form of communication is called IP interconnectivity or IPIC. IPIC provides similar capabilities and qualities of service to those provided by ISC over SNA.
• Intersystem communication over SNA (ISC over SNA) allows communication between CICS and non-CICS systems or CICS systems that are not in the same z/OS image or sysplex. These intercommunication facilities can also be used between CICS regions in the same z/OS image or sysplex.

The CICS-supplied mirror program DFHMIRS is defined as a threadsafe program. For supported CICS facilities, over IPIC connections only, the remote CICS region uses a threadsafe mirror transaction and runs the request on an L8 open TCB whenever possible. For threadsafe applications that issue commands for functions on remote CICS systems using IPIC connections, the reduction in TCB switching improves application performance compared to other intercommunication methods. The use of open TCBs also provides significant potential throughput improvements between CICS regions.

For more information about CICS intercommunication, see Getting started with intercommunication and Introduction to CICS intercommunication.

IPIC high availability feature

The IPIC high availability feature provides a single point of access to a cluster of CICS TS regions via a TCP/IP network. This ensures resilience of access to the cluster as a whole, for both planned and unplanned outages of individual regions within the cluster. For more information, see IPIC high availability feature.

Dynamic transaction routing

When you define transactions to CICS, you can describe them as remote or local. Local transactions are always executed in the terminal-owning region; remote transactions can be routed to other regions connected to the terminal-owning region by IPIC, MRO, or APPC (LUTYPE6.2) ISC links. Using dynamic transaction routing across a CICSplex, compared with static routing, can improve performance and availability.

For more information about dynamic transaction routing, see Dynamic transaction routing. For more information about writing a dynamic routing program, see Writing a dynamic routing program.

CICSPlex SM provides a dynamic routing program that supports both workload routing and workload separation.

Distributed program link

CICS distributed program link enables CICS application programs to run programs that are in other CICS regions by shipping program-control LINK requests. This allows you to write an application without knowledge of the location of the requested programs. For more information, see Distributed Program Link (DPL).

CICS Interdependency Analyzer for z/OS (CICS IA)

CICS Interdependency Analyzer (CICS IA) is a productivity tool that is used to discover and analyze CICS resources and identify relationships between them.

CICS IA dynamically discovers runtime relationships among key resources within your CICS system. It does this by monitoring applications for API and SPI commands along with optional DB2®, IMS, WebSphere® MQ, and COBOL calls to give you a complete picture of your application and the interactions and resources that are referenced along with their inter-relationship. CICS IA can help you analyze applications for Threadsafe considerations to improve the overall execution efficiency. CICS IA can help you analyze applications for affinities, which might impact the roll-out of CICS applications into a Parallel Sysplex.

For more information about CICS IA, see CICS Interdependency Analyzer for z/OS.

For more information about threadsafe programs, see Threadsafe programs.

For more information about affinities, see Affinity and Application affinities.

CICS Deployment Assistant for z/OS (CICS DA)

CICS Deployment Assistant (CICS DA) can be used to discover running CICS regions and their connectivity to other subsystems such as DB2 and WebSphere MQ. It also can assist in building the CICSplex infrastructure and setting up the workload management infrastructure.

For more information about CICS DA, see CICS Deployment Assistant for z/OS