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:
- Set the System Initialization (SIT) parameter TCPIP=YES.
- 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.
- 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.
- Use the following command to install the TCPIPSERVICE definition:
CEDA INS TCPIPSERVICE(service-name) GROUP(group-name)
- 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 determinedSENDSESSIONS 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.