Configuring Comm. Bridge Server Connections › Transport API – Additional Details › TCP/IP/Socket Connections › z/OS CICS TCP/IP – CICS Socket Listener

z/OS CICS TCP/IP – CICS Socket Listener

• The CICS Socket Listener is the preferred CICS TCP/IP connection mechanism. This version supports a non persistent socket which means a new socket connection is created for each client/server request/response. All supported client side runtimes have been modified to allow support for this non persistent behavior.
• If this listener is used with the Comm Bridge the server configuration details must be set with the CICS Socket Listener check box selected as mentioned in the Details for Configuring TCP/IP (Sockets) section above.

The CICS Socket Listener implementation uses the CICS program TISRVLIS. TISRVLIS listens for connection requests from the Comm Bridge using its well-known port address. When a request is accepted TISRVLIS passes the connection request to the appropriate CA Gen application server. The CA Gen application server then assumes responsibility for creating, managing, and closing the socket connection.

When DPS application processing is complete, a response message is passed from the server application to the Comm. Bridge and on to the DPC application.

The following diagram illustrates a Distributed Process application prior to a DPC request being serviced by the target server environment TISRVLIS process. The Comm. Bridge initiates a bind socket request to the TISRVLIS process's well-known port address.

The following diagram illustrates a Distributed Process application at the time the Comm. Bridge request has been accepted and the application server process has taken responsibility for the connection. The TISRVLIS process is now available to listen for additional connections from the Comm. Bridge.

The following diagram illustrates a Distributed Process application after the server application has completed. The socket connection used for the transaction has been closed. The TISRVLIS process is handling another connection request from the Comm Bridge and the cycle repeats.

Installation and configuration information for the TISRVLIS component appears in the Installation Guide for Host Encyclopedia and Host Construction Installation Guide and in the z/OS Implementation Toolset Installation Guide for z/OS.