CICS Transaction Server Version 3.1 introduces a new approach that provides an easy and more flexible mechanism for exchange of large volumes of structured parameter data between CICS programs. This new approach is provided by two new capabilities known as channels and containers.
A container is a named reference to a CICS-managed storage area that can hold any form of application data. A container may be any size and can hold data in any format that the application requires. An application can reference any number of containers. CICS provides EXEC API verbs to create, delete, reference, access, and manipulate a container as well as to associate it with a channel.
A channel is a uniquely named reference to a collection of application parameter data held in containers. A channel is analogous to a COMMAREA, but it does not have the constraints of a COMMAREA. CICS provides EXEC API , which associates a named channel with a collection of one or more containers. This is an easy way of grouping parameter data structures which may pass to a called application. CICS destroys a channel when it can no longer be referenced, which means, when a channel becomes out of scope.