Certain resources are automatically activated by VTAM®. Some internally maintained resources are automatically activated when the message "VTAM INITIALIZATION COMPLETE" is issued. These resources can be displayed, but cannot be activated or deactivated by an operator. The following resources are automatically activated:

• VTAMSEG application program major node:
  • VTAM (or name from the CDRM definition statement for this VTAM)
  • ISTATA00
  • ISTNOP
  • ISTPDCLU
  • ISTAPNCP
• VTAMSEG2 application program major node:
  • *?-?* (model application program definition for Telnet server shared ACBs)
  Note: The definition of the model application program for Telnet server shared ACB names cannot be displayed.
• ISTPUS PU (or name from HOSTPU start option) type 5 node
  • ISTGROUP
• ISTPDILU predefined independent LU major node
• ISTADJCP adjacent CP major node
• ISTCDRDY dynamic cross-domain resource major node
  Note: The ISTCDRDY major node can be deactivated and activated by an operator. For further information, see Dynamic definition of independent LUs.
• ISTRTPMN rapid transport protocol major node
• ISTTRL transport resource list major node
• ISTLSXCF local SNA major node
  Note: ISTLSXCF can also be deactivated and activated by the operator.

VTAM dynamically builds and activates transport resource list elements (TRLEs) within the ISTTRL major node for some TCP/IP communication interfaces. All of these TRLEs are created when needed, but cannot be deleted. These dynamic TRLEs are created with the following naming convention:

IUTSAMEH

This TRLE is created for communication between multiple TCP/IP stacks on the same MVS™ image, and for communication between TCP/IP and VTAM for Enterprise Extender.

IUTIQDIO

This TRLE is created for TCP/IP dynamic XCF communications over HiperSockets™ devices. Up to 10 subchannel addresses are allocated: one READ and one WRITE device, and eight DATAPATH devices.

IUTIQDxx

This TRLE is created when TCP/IP activates a HiperSockets interface (defined by using either the DEVICE/LINK statements for IPAQIDIO or the IPv6 INTERFACE statement for IPAQIDIO6) with a CHPID parameter of xx. Up to 10 subchannel addresses are allocated: one READ and one WRITE device, and eight DATAPATH devices.

IUTIQ4xx

This TRLE is created when TCP/IP activates a HiperSockets interface (defined by using the IPv4 INTERFACE statement for IPAQIDIO) with a CHPID parameter of xx. Up to 10 subchannel addresses are allocated: one READ and one WRITE device, and eight DATAPATH devices.

IUTIQXxx

This TRLE is created for TCP/IP dynamic Internal Queued Direct I/O extensions (IQDX) function IPv4 communications over HiperSockets devices that are connected to the intraensemble data network (IEDN). The value xx is the OSX CHPID number that is associated with this IQDX TRLE. Up to 10 subchannel addresses are allocated: one READ and one WRITE device, and eight DATAPATH devices.

IUTIQ6xx

This TRLE is created for TCP/IP dynamic IQDX IPv6 communications over HiperSockets devices that are connected to the intraensemble data network (IEDN). The value xx is the OSX CHPID number that is associated with this IQDX TRLE. Up to 10 subchannel addresses are allocated: one READ and one WRITE device, and eight DATAPATH devices.

IUTXT0xx

This TRLE is created when TCP/IP activates an MPCIPA INTERFACE with CHPIDTYPE OSX and a CHPID parameter of xx. Up to 19 subchannel addresses are allocated: one READ and one WRITE device, and 17 DATAPATH devices.

IUTMT0xx

This TRLE is created when TCP/IP activates a dynamically defined OSM interface, where VTAM assigned CHPID xx for this communication. Up to 11 subchannel addresses are allocated: one READ and one WRITE device, and nine DATAPATH devices.

IUTnpfid

This TRLE is created when TCP/IP activates an IPAQENET or IPAQENET6 interface with CHPIDTYPE OSD with Shared Memory Communications - RDMA (SMC-R) specified or taken as the default, and SMC-R is enabled on the system. The npfid value is derived from the PORTNUM and PFID values on the SMCR parameter of the GLOBALCONFIG statement in the TCP/IP profile. For example, IUT20018 indicates that the PORTNUM value is 2 and the PFID value is 0018. If PORTNUM is not specified, the default value is 1. No subchannels are associated with this TRLE.

ISTTlsrs

TRLEs of this name are created when VTAM is started with either XCFINIT=YES (the default) or XCFINIT=DEFINE and another VTAM joins the XCF group (ISTXCF).

• ls is the two character &SYSCLONE value of the VTAM on the local MVS image
• rs is the two character &SYSCLONE value of the VTAM on the partner MVS image.

TCP/IP uses these TRLEs in one of the following situations:

• DYNAMICXCF is specified on the IPCONFIG or IPCONFIG6 statement and device or interface definitions are dynamically created to other VTAMs with XCF connectivity.
• DEVICE/LINK statements of type MPCPTP contain a device name that is the CPNAME or SSCPNAME of another VTAM with XCF connectivity.
• INTERFACE definitions of type MPCPTP6 contain a TRLENAME that is the CPNAME or SSCPNAME of another VTAM with XCF connectivity.

IUTtdddd

This TRLE is created when TCP/IP activates a CDLC, CLAW, Hyperchannel, CTC, or LCS device.

• t identifies the type of device that is dynamically created:
  • C - TCP/IP CDLC
  • W - TCP/IP CLAW
  • H - TCP/IP Hyperchannel
  • X - TCP/IP CTC
  • L - TCP/IP LCS
• dddd identifies the read device address for this device.