CICS Transaction Server for z/OS three-tier connectivity

The CICSRequest node support in IBM® App Connect Enterprise can provide communication with CICS® Transaction Server for z/OS® through CICS TG (three-tier connection).

The CICSRequest node also supports direct communication with CICS (two-tier connection) by sending Distributed Program Link (DPL) requests over TCP/IP-based IP InterCommunications (IPIC) protocol. For more information about two-tier connections, see CICS Transaction Server for z/OS two-tier connectivity.

A three-tier connection from IBM App Connect Enterprise to CICS through CICS TG can be made by configuring the CICS Server and CICS Transaction Gateway URL CICS Connection policy properties.

The following diagram shows how IBM App Connect Enterprise can make a connection to CICS through CICS TG by using the CICS Connection policy.
The diagram shows how IBM Integration can connect to CICS Transaction Server for z/OS through CICS Transaction Gateway for Multiplatforms by using a CICS Connection policy.

For more information about configuring the CICS server and CICS Transaction Gateway URL CICS Connection policy properties to make a three-tier connection, see CICS Connection policy (CICSConnection).

The three-tier connection to CICS through CICS TG connection model is based on the following rules:

  • The number of connections that can be made to CICS TG is determined by the maximum number of simultaneous CICS requests in progress. Ensure that the Connection Manager and Worker Thread resources in your CICS TG deployment have sufficient capacity to handle the number of required IBM App Connect Enterprise connections.
  • The CICS APPLID and CICS APPLID qualifier properties in the CICS Connection policy can be used to identify the IBM App Connect Enterprise connection within CICS TG. In addition, any CICS tasks that are started through the policy each contain point of origin information, including the specified client APPLID and qualifier, which you can find in the CICS task association data.
  • Unlike two-tier connections, there is no restriction about sharing client APPLIDs between integration servers because the connection is made to CICS TG, and not to CICS directly.

For more information about configuring the CICSRequest node to get connection details from a CICS Connection policy, see Changing connection information for the CICSRequest node.