Three CICS® transactions are supplied with CICS ONC RPC:
The connection manager is a transaction that allows you to enable and disable CICS ONC RPC, and configure and inquire on it. You run the connection manager transaction as required, and several instances of it can be active at the same time. The connection manager is described in Configuring CICS ONC RPC using the connection manager.
The server controller monitors the TCP/IP for MVS™ interface for client requests, and starts instances of the alias transaction, using EXEC CICS START, to service them. The server controller is a transaction of long duration. It is started by the connection manager when CICS ONC RPC is enabled, and stopped when CICS ONC RPC is disabled. Only one instance of the server controller can be active in a CICS system.
CICS ONC RPC supplies one alias program. Multiple instances of the alias transaction can be run in parallel, each in response to a client request.
An alias is started by the server controller for each client request that arrives to be processed, as shown in Figure 35. This allows CICS ONC RPC to process many client requests concurrently.
The alias program uses EXEC CICS LINK to transfer control to the CICS program.