One channel, several programs (a component)

In Figure 1, there is a single channel to the top-level program in a set of inter-related programs. The set of programs within the shaded area can be regarded as a component. The client program "sees" only the external channel and has no knowledge of the processing that takes place nor of the existence of the back-end programs.

Inside the component, the programs can pass the channel between themselves. Alternatively, a component program could, for example, pass a subset of the original channel, by creating a new channel and adding one or more containers from the original channel.

Figure 1. A "component"—a set of related programs invoked through a single external channel. "CH" indicates that the programs within the component can pass channels between themselves.
The picture shows a box representing a component. Within the box are several programs that interact with one another. A client program, outside the box, issues an EXEC CICS LINK PROGRAM('payr') CHANNEL('payroll') call to invoke the top-level program within the component.