ACF/VTAM definition for CICS

When you define your CICS® system to ACF/VTAM, include the following operands in the VTAM® APPL statement:

MODETAB=logon-mode-table-name
This operand names the VTAM logon mode table that contains your customized logon mode entries. (See ACF/VTAM LOGMODE table entries for CICS.) You may omit this operand if you choose to add your MODEENT entries to the IBM® default logon mode table (without renaming it).
AUTH=(ACQ,SPO,VPACE[,PASS])
ACQ is required to allow CICS to acquire LU type 6 sessions. SPO is required to allow CICS to issue the MVS™ MODIFY vtamname USERVAR command. (For further information about the significance of USERVARs, see the CICS/ESA 3.3 CICS XRF Guide.) VPACE is required to allow pacing of the intersystem flows.

PASS is required if you intend to use the EXEC CICS ISSUE PASS command, which passes existing terminal sessions to other VTAM applications.

VPACING=number
This operand specifies the maximum number of normal-flow requests that another logical unit can send on an intersystem session before waiting to receive a pacing response.

Take care when selecting a suitable pacing count. Too low a value can lead to poor throughput because of the number of line turnarounds required. Too high a value can lead to excessive storage requirements.

EAS=number
This operand specifies the number of network-addressable units that CICS can establish sessions with. The number must include the total number of parallel sessions for this CICS system.
PARSESS=YES
This option specifies LU type 6 parallel session support.
SONSCIP=YES
This operand specifies session outage notification (SON) support. SON enables CICS, in particular cases, to recover a failed session without requiring operator intervention.
APPC=NO
Start of changeAPPC=NO is required for CICS. This setting is the default. If you do not use APPC=NO, you receive message DFHZC2400E, referencing the VTAM return code 1013.End of change

For further information about the VTAM APPL statement, refer to the OS/390 eNetwork Communications Server: SNA Resource Definition Reference manual.

ACF/VTAM LOGMODE table entries for CICS

For APPC sessions, you can use the MODENAME option of the CICS DEFINE SESSIONS command (see Defining APPC links) to identify a VTAM logmode entry that in turn identifies the required entry in the VTAM class-of-service table. Every modename that you supply, when you define a group of APPC sessions to CICS, must be matched by a VTAM LOGMODE name. All that is required in the VTAM LOGMODE table are entries of the following form:

  MODEENT LOGMODE=modename
  MODEEND

An entry is also required for the LU services manager modeset (SNASVCMG):

  MODEENT LOGMODE=SNASVCMG
  MODEEND

If you plan to use autoinstall for single-session APPC terminals, additional information is required in the MODEENT entry. For programming information about coding the VTAM LOGON mode table, see the CICS Customization Guide.

For CICS-to-IMS™ links that are cross-domain, you must associate the IMS LOGMODE entry with the CICS applid (the generic applid for XRF systems), using the DLOGMOD or MODETAB parameters.

Related concepts
Installation considerations for multiregion operation
Considerations for IMS
Related tasks
Defining APPC links
Related reference
Modules required for ISC
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