CICS® transaction routing allows terminals connected to one CICS system to run with transactions in another, connected, CICS system. This means that you can distribute terminals and transactions around your CICS systems and still have the ability to run any transaction with any terminal.
Figure 6 shows a terminal connected to one CICS system running with a user transaction in another CICS system. Communication between the terminal and the user transaction is handled by a CICS-supplied transaction called the relay transaction.
Two different CICS products must be connected by an LU6.2 link. Transaction routing over LU6.1 links is not supported.
In transaction routing, the term terminal is used in a general sense to mean such things as an IBM® 3270, or a single-session APPC device, or an APPC session to another CICS system, and so on. All terminal and session types supported by CICS on System/390® are eligible for transaction routing, except those given in the following list:
CICS Transaction Server for Windows, CICS/400, and CICS on Open Systems support minimum BMS. (They support SEND TEXT.) Only CICS on System/390 systems support batch data interchange, standard BMS, and full BMS. Depending on these product capabilities, a user transaction can use CICS terminal control, BMS, or batch data interchange facilities to communicate with the terminal, as appropriate for the terminal or session type. Mapping and data interchange functions are performed in the application-owning system (CICS B in Figure 6). BMS paging operations are performed in the terminal-owning system (CICS A in Figure 6).
Pseudoconversations are supported (except when the terminal is an APPC session), and the various transactions that make up a pseudoconversation can be in different systems.