System Generation Statements › TCP/IP Statement—Defines TCP/IP Runtime Environment › TCP/IP Statement Parameters

TCP/IP Statement Parameters

TCP/ip and TCPip

These are equivalent keywords that can be used the same way everywhere. They can be specified in SYSGEN definitions or DCMT commands.

DEFault STATus is

Specifies the status of TCP/IP support in CA IDMS. OFF disables TCP/IP support for CA IDMS at startup. ON enables support. The default is ON if an ADD TCP/IP statement is coded. If the TCP/IP entity is not defined to the system, the default is OFF.

Note:

• For compatibility with earlier releases, if the TCP/IP entity is not defined to SYSGEN, but the same system contains the definition of an enabled SOCKET line, TCP/IP is automatically enabled during startup. A warning message is displayed to the log recommending the use of the TCP/IP SYSGEN entity.
• The default TCP/IP status value defined to SYSGEN can be overwritten at startup by the new TCP/IP_STATUS=ON/OFF SYSIDMS parameter, or it can be changed dynamically at runtime using the new DCMT VARY TCP/IP command.

DEFault TCP_NODelay option is

Specifies the default value for the NO_DELAY SOCKET option. Unless overridden for a specific socket connection, this is the value that will be used for all communication. The default value is OFF, meaning that a delay may be experienced between consecutive sends in order to optimize overall data movement.

Note: For more information about the TCP_NODELAY socket option, see the GETSOCKOPT and SETSOCKOPT SOCKET functions in the CA IDMS Callable Services Guide.

DEFault STACk is

Specifies the default stack to be used by the DC/UCF system.

stack-name

Identifies the name of the stack to be used as a default.

DEFault

Specifies that the CA IDMS assigned default stack is to be used. DEFAULT is the default.

The default stack for a DC/UCF system varies by operating system.

• On z/OS, the operating system assigns a specific stack as the default stack. Unless that stack is explicitly excluded from use by SYSGEN or SYSIDMS parameters, CA IDMS uses the operating-system assigned default stack. If the default stack has been excluded, CA IDMS chooses the first active stack from the list of stacks as the default.
• On z/VM, the default stack is the first stack in the list of stacks.

INClude/EXClude STack stack-spec

Controls or limits the stacks that can be used by the socket applications running in the CA IDMS system. This option is useful only in a multiple stack environment where multiple TCP/IP stacks run concurrently; it is ignored on systems where only one TCP/IP stack is active. It is used differently depending on the operating system:

• On z/OS, the INCLUDE or EXCLUDE list is used to customize the default stacks list returned by the operating system when CINET is active. Both lists are mutually exclusive. If no INCLUDE or EXCLUDE list is specified, all stacks in the list returned by the operating system are included.

  If specified, the resulting list of stacks depends on the type of list being defined:

  • INCLUDE List—This list is built by excluding all the stack names that are not present in the SYSGEN INCLUDE list.
  • EXCLUDE List—This list is built by excluding all the stack names that are present in the SYSGEN EXCLUDE list.

  Wildcards can be used as special names for stack-spec to define groups of stack names starting with the same pattern. When wildcards are used in the INCLUDE or EXCLUDE list, the EXCEPT list can be used to refine the set of included or excluded stacks by excluding specific stacks.

  Wildcards can also be used for stack-spec in the EXCEPT list if they represent a sub-group of names from a larger group declared in the INCLUDE or EXCLUDE list. See examples at the end of this section.

• On z/VM, only an INCLUDE list is available. Use the INCLUDE list to define the full list of stacks to use in the CA IDMS system. Wildcards are not accepted.

  This list can be used to replace the r16 definitions using the SYSTCPD file and the existing SYSIDMS parameters; these definitions are ignored when the stacks are defined through SYSGEN.

An empty list can be specified for the INCLUDE, EXCLUDE or EXCEPT list in order to remove all entries from the corresponding list. Duplicate names are ignored when specified within the same list of stacks.

MAXimum NUMber of SOCkets is max-socket

Specifies the maximum number of sockets that can be created globally in the DC/UCF system. max-socket is a positive number between 1 and 65535. If DEFAULT is specified, a default value is assigned at startup. This default value depends on the operating system: 65535 on z/OS, 8000 on z/VSE, and 512 on z/VM.

The maximum number of sockets that can be created in one address space can also be limited by the operating system, for example, through USS definitions under z/OS.

MAXimum NUMber of SOCkets per TASk is max-socket-per-task

Specifies the maximum number of sockets that can be created by a single task in the DC/UCF system. The maximum value and the default value for this parameter are both equal to the value assigned at runtime to max-socket. If the max-socket-per-task value is greater than max-socket, it is truncated.

PLUgin MODule is plugin module

Specifies the name of the plug-in module that implements support for specific TCP/IP stack implementations. The only plug-in module name that is accepted is RHDCD1IP; this is also the default value.

Note: In prior releases, the name of the plug-in module was specified on the MODULE is plug-in clause of the SOCKET LINE SYSGEN statement. While this clause is still supported for upward compatibility, it is no longer required and the name of the plug-in module should now be specified using the PLUGIN MODULE clause of the new system generation TCP/IP statement.

SERvices FILe is

Defines the file to be used for translating service names to port numbers and vice versa.

file-name

Specifies the ddname (z/OS and z/VM) or the file name (z/VSE) of the services file.

If the data set or file corresponding to file-name cannot be found at runtime (DD card not specified in the startup JCL or data set not cataloged), an error message is written to the log file. Subsequent calls to the GETSERVBYNAME or GETSERVBYPORT socket function returns a specific ERRNO code.

OFF

Indicates that no services file is available and port number/service name resolution is not supported. OFF is the default.

CASe

Indicates whether the service name specified on input to a GETSERVBYNAME socket function is case-sensitive or case-insensitive. The default value is case-sensitive.

Note: For more information about the Services File and the Services Resolver, see the CA IDMS System Operations Guide.