Configuring CICS ONC RPC

Stabilized feature: CICS® support for Open Network Computing Remote Procedure Call (ONC RPC) is stabilized. Consider exposing and orchestrating applications as API services by using z/OS Connect Enterprise Edition or CICS web services, or by writing web applications in Java or Node.js. See also Stabilization notices and discontinued functions.

CICS ONC RPC allows client applications to access CICS programs by calling them as remote procedures using the ONC RPC format. Follow this information to set up CICS ONC RPC.

Before you begin

Check that the following prerequisite conditions are met:

Clients

Clients must access servers on CICS ONC RPC over a TCP/IP network.

Client systems must use a library compatible with the library for ONC RPC Version 3.9, as this is the ONC RPC version supported by TCP/IP for MVS (Versions 2.2.1 and 3.1). To communicate over a TCP/IP network, appropriate hardware and software must be in place.

z/OS®
The following items must be installed on the z/OS system for CICS ONC RPC to run.
  • TCP/IP for z/OS Version 2.2.1 or above. TCP/IP for z/OS ports must be made available for use by the CICS region involved.
  • Language Environment®. This provides the C runtime libraries that are a prerequisite for running CICS ONC RPC.
  • If you are using RPCGEN, or writing your own XDR routines, you need a C compiler to compile RPCGEN output and your XDR routines.
CICS

CICS must be set up for Language Environment support.

Note: TCP/IP for MVS CICS Sockets is not a prerequisite for CICS ONC RPC.
TCP/IP for z/OS

CICS ONC RPC and TCP/IP for z/OS CICS Sockets Version 2.2.1 cannot operate together from one CICS region to one TCP/IP for z/OS region. You are advised to run CICS Sockets and CICS ONC RPC in different CICS regions.

TCP/IP for z/OS Version 3.1 users do not have this problem; CICS Sockets and CICS ONC RPC can both be run from the same CICS region.

TCP/IP for z/OS 2.2.1

There are no prerequisites for running CICS ONC RPC.

Note: CICS ONC RPC and TCP/IP for z/OS CICS Sockets Version 2.2.1 cannot operate together from one CICS region to one TCP/IP for z/OS region. You are advised to run CICS Sockets and CICS ONC RPC from different CICS regions.
TCP/IP for z/OS 3.1
The following PTF is a prerequisite for running CICS ONC RPC:
  • A PTF, number UN79963, related to the use of the xdr_text_char XDR library function.
Note: CICS ONC RPC and TCP/IP for z/OS CICS Sockets Version 2.2.1 cannot operate together from one CICS region to one TCP/IP for z/OS region. You are advised to run CICS Sockets and CICS ONC RPC from different CICS regions.
Storage requirements

Except where otherwise noted, the storage used by CICS ONC RPC is obtained from CICS subpools.

When CICS ONC RPC is enabled, its storage requirements are as follows:
  • 40 KB base storage
  • 100 bytes for each registered 4-tuple.
For each client request being processed the following storage is required:
  • z/OS-controlled storage used by the inbound XDR routine for internal data structures
  • Storage used by the inbound XDR routine for the data structure it builds for the Decode function
  • Storage for the CICS program communication area
  • Storage used by the alias transaction while running the CICS program
  • Storage used by the Encode function to create a data structure for the outbound XDR routine
  • z/OS-controlled storage used by the outbound XDR routine

Setting up CICS ONC RPC

Perform the following tasks:

Create the CICS ONC RCP data set

The JCL to create the CICS ONC RPC data set is provided in the DFHCOMDS job.

The data set is defined as a VSAM key-sequenced data set by a DEFINE CLUSTER command like the following:
DEFINE CLUSTER (                    -
  NAME( xxxxxxxx.CICSONC.RESOURCE ) -
  CYL ( 2 1  )                      -
  KEYS( 19 0 )                      -
  INDEXED                           -
  VOLUME ( vvvvvv )                 -
  RECORDSIZE( 150 150 )             -
  FREESPACE( 5 5 )                  -
  SHAREOPTIONS( 1 )                 -
  )

The job to define the data set must be run before you start the connection manager for the first time.

(Optional) Switch dump formatting for CICS ONC RPC
To switch dump formatting on for CICS ONC RPC (and for all running features), change the IPCS VERBEXIT control statement. The JCL entry for dump formatting is as follows:
IPCS VERBEXIT DFHPD760 FT=2

The VERBEXIT provides a formatted dump of CICS ONC RPC control blocks.

Modify z/OS Communications Server data sets
You can define the CICS TS region to z/OS Communications Server in the TCPIP.PROFILE data set to reserve specific ports for ONC RPC applications. This is described in z/OS Communications Server: IP Configuration Guide.
Important: CICS ONC RPC is part of the CICS Transaction Server base. None of the IBM®-supplied programs for CICS ONC RPC can be moved to CICS Transaction Server from earlier releases.

What to do next