These steps provides the minimum information that you need to modify CICS® startup.

The following are the required modifications to the startup of CICS:

1. You must concatenate the data set SEZATCP to the DFHRPL DD. This data set contains all the other IP CICS TCP/IP modules.
2. Add a TCPDATA DD entry for the IP CICS sockets output messages (see Defining the TCPM transient data queue for CICS TCP/IP).
3. The SYSTCPD DD explicitly identifies which data set is to be used to obtain the parameters defined by TCPIP.DATA. This is used to select the stack you want to use if there are multiple TCP/IP stacks on this system. See z/OS Communications Server: IP Configuration Guide for further information.
4. The CICS System Initialization Table (SIT) override might contain the following information. See the CICS system initialization information at http://www-01.ibm.com/software/htp/cics/library/ for more details about setting CICS SIT parameters:
   • GMTEXT= WELCOME TO CICS/TS WITH z/OS CS TCP/IP SOCKETS INTERFACE
   • MCT=SO

     If you want IP CICS sockets to provide performance data then include the IP CICS Sockets Monitor Control Table (MCT) entries in your MCT along with any appropriate monitor SIT controls.

   • PLTPI=SI

     If you want IP CICS sockets to start at Program Load Table (PLT) phase 2 then include EZACIC20 in an appropriate startup PLT.

   • PLTSD=SD

     If you want IP CICS sockets to shutdown at PLT phase 1, then include EZACIC20 in an appropriate shutdown PLT.

   • PLTPIUSR=PLTUSER

     PLT User ID. Specify the appropriate user ID to start the IP CICS socket interface and listeners.

5. The following CICS SIT parameters affect the IP CICS socket interface when it is configured to use the CICS Open Transaction Environment. CICS/TS V2R2 or later is required for this support.
   • MAXOPENTCBS=50

     When specifying the EZACICD TYPE=CICS,OTE=YES configuration option, carefully consider this value; it is the size of the CICS managed open API, L8, TCB pool. This pool is used by the IP CICS socket interface and other open API-enabled task-related user exits such as DB2®. Use the CEMT SET DISPATCHER command to dynamically alter this value.

   • FORCEQR

     User programs that are defined to CICS as THREADSAFE are executed on the quasi-reentrant TCB. Use the CEMT SET SYSTEM command to dynamically alter this value.

6. Write the Resolver trace to either a dataset or JES spool.
7. The information is used by IP CICS C Sockets API programs for user messages.