Configuring IPIC on CICS Transaction Server for z/OS

Perform these steps to configure IPIC on CICS® Transaction Server for z/OS®.

CICS Transaction Gateway can send IPIC requests over TCP/IP to CICS Transaction Server for z/OS V3.2 and later. To perform this configuration:
  1. Set the System Initialization (SIT) parameter TCPIP=YES.
  2. Define the TCP/IP address and host name for the z/OS system. By default, they are defined in the PROFILE.TCPIP and TCPIP.DATA data sets.
  3. Add a TCP/IP listener to CICS. Use the following CEDA command to define a TCPIPSERVICE in a group:
    CEDA DEF TCPIPSERVICE(service-name) GROUP(group-name)
    Ensure that the group in which you define the service is in the startup GRPLIST, so that the listener starts when CICS is started. Key fields are explained as follows:
    POrtnumber
    The port on which the TCP/IP service listens.
    PRotocol
    The protocol of the service is IPIC.
    TRansaction
    The transaction that CICS runs to handle incoming IPIC requests. Set it to CISS (the default).
    Backlog
    The number of TCP/IP requests that are queued before TCP/IP starts to reject incoming requests.
    Ipaddress
    The IP address (in dotted decimal form) on which the TCPIPSERVICE listens. For configurations with more than one IP stack, specify ANY to make the TCPIPSERVICE listen on all addresses.
    SOcketclose
    Whether CICS waits before closing the socket after issuing a receive for incoming data on that socket. NO is recommended for IPIC connections, to ensure that the connection from the CICS Transaction Gateway always remains open.
  4. Use the following command to install the TCPIPSERVICE definition:
    CEDA INS TCPIPSERVICE(service-name) GROUP(group-name)
  5. Choose whether to predefine or to autoinstall IPIC connections in CICS Transaction Server for z/OS. Specific inbound connections can be defined for different configurations using the CICS definition, IPCONN, or the connection can be autoinstalled using either the default or a customized autoinstall program. When CICS TG connects to CICS it flows the fully-qualified APPLID defined for the Gateway daemon or local mode application and if this matches that defined on an IPCONN definition, that definition is used to install the connection. If there is no matching IPCONN definition, the connection is autoinstalled. For further information on setting the fully-qualified APPLID for IPIC connections see IPIC server connections.

    To customize autoinstalled IPIC connections, for example, to configure security, an IPCONN definition must be created with the customized attributes to act as a template and this definition must be referenced as the template in a customized IPCONN autoinstall user program. The name of the autoinstall user program must be specified on the URM option of the installed TCPIPSERVICE definition. For further information on setting security on IPIC connections see IPIC connection security.

    When creating an IPCONN definition for a CICS TG to CICS connection, the SENDCOUNT parameter must be set to zero, unlike CICS to CICS connections for which the SENDCOUNT must not be zero.

Setting session limits

The number of simultaneous transactions, or CICS tasks, that are possible over the connection is determined as follows:

Table 1. How the number of simultaneous transactions possible over an IPIC connection is determined
SENDSESSIONS setting in CICS Transaction Gateway IPCONN Receive Count setting in CICS Transaction Server for z/OS Number of simultaneous transactions allowed
Set Set (on IPCONN resource definition or customized autoinstall) The lesser of the two values is used.
Set Not set (default autoinstall) The value of the CICS Transaction Gateway SENDSESSIONS setting is used.
Not set Set (on IPCONN resource definition or customized autoinstall) The value of the CICS Transaction Server for z/OS IPCONN Receive Count setting is used.
Not set Not set (default autoinstall) A value of 100 is used.
Note: For local mode IPIC connections the CICS Transaction Gateway requests 100 send sessions by default. For JEE applications, the number of sessions can be configured using the ipicSendSessions connection factory property. For Java base class applications, the number of sessions can be configured using the CTG_IPIC_SENDSESSIONS Java property.

Each active session uses one CICS task and the maximum number of sessions allowed is 999. CICS Transaction Gateway allocates 300 KB of memory for each session. If all the defined sessions are in use, any new requests receive an ECI_ERR_RESOURCE_SHORTAGE error.

For more information on configuration file definitions for IPIC, see IPICSERVER section of the configuration file.


Information Information

Feedback


Timestamp icon Last updated: Tuesday, 19 November 2013


https://ut-ilnx-r4.hursley.ibm.com/tg_latest/help/topic/com.ibm.cics.tg.doc//ctgunx/c0100120.html