The roles of a CICS region in a CICSplex

In a CICSplex containing many CICS regions, it is convenient to assign regions to perform particular roles for the applications that they support.

These roles are as follows:
Transport-owning region
A CICS region that connects a CICSplex to your communication network. Transaction requests received by a transport-owning region are passed to an application-owning region for processing.
Terminal-owning region
A CICS region that connects terminals and other devices, including printers, to the CICSplex. Transaction requests received by a terminal-owning region are passed to an application-owning region for processing.
Application-owning region
A CICS region that manages application programs. Requests for data are passed to a data-owning region.
Data-owning region
A CICS address space that manages access to files and databases.
File-owning region
A CICS address space that manages access to files. A file-owning region is a specific type of data-owning region.

All CICS regions can perform all the roles and, in some cases, it is appropriate to combine some of the roles in one region.