CICS - Intercommunication


The mutual communication that takes place between two or more systems is known as intercommunication.

Benefits of Intercommunication

The important benefits of intercommunication are as follows −

  • We do not need to replicate the data on all the systems.

  • Users need not hold connections to multiple systems for accessing the data stored on them.

  • It improves the performance of the application.

Basic Terminologies

One must have a knowledge of basic terminologies used in the CICS system. Following are the basic terms −

Local System

A local system is a system that initiates a request for intercommunication.

Local Resource

A local resource is a resource that lies on the local system.

Remote System

A remote system is a system that is initiated as a result of an intercommunication request.

Remote Resource

A remote resource is a resource that lies on the remote system.

MVS Sysplex

MVS Sysplex is a configuration of multiple MVS operating systems. They work as a single system by sharing functions and programs.


CICSPlex is commonly described as a set of interconnected CICS regions that process customer workload. A CICSPlex is a set of interconnected CICS regions that own Terminals, Applications, Resources, etc.

Intercommunication Methods

There are two ways in which CICS can communicate with other systems −

  • MRO − Multi Region Operation is used when two CICS regions within the same MVSPLEX needs to communicate with each other.

  • ISC − Inter System Communication is used when a CICS region in a LOCAL server has to communicate with a CICS region in the REMOTE server.