Dynamic definition of dependent LUs

Dependent logical units that are attached through an IBM® 3174 control unit can be defined dynamically to a VTAM® network when the device that contains the logical units powers on, rather than during major node activation. See Figure 1.

VTAM defines dependent logical units dynamically by using model logical unit definitions, rather than predefined definitions. The dynamically defined logical unit definitions are updated, if needed, each time the device containing the logical units powers on. You can use this function to add, change, or relocate dependent logical units from a VTAM network without reactivating the major node.

Figure 1. Dynamic definition of dependent LUs. Host A01 is an interchange node (ICN).

A diagram that shows the interchange node A01 is attached to an IBM 3174 control unit.

For more information about this function, including the process VTAM follows to dynamically define dependent logical units, see the z/OS Communications Server: SNA Network Implementation Guide.

To enable dynamic definition of dependent logical units, you must code an LU group major node. The LU group major node defines one or more model LU groups, each of which contains a list of model LU definition statements. For a sample LU group major node, see LU group major node.

In addition to coding an LU group major node, you must also code the LUGROUP operand on the PU definition statement for the 3174. If you use the SDDLU (selection of definitions for dependent LUs) exit routine, you must also code the LUSEED operand on the 3174's PU definition statement.

In the sample local SNA major node named A01LSNA, the VBUILD definition statement identifies it as a local SNA major node (TYPE=LOCAL).

In the PU definition statement, PU3174 is the 3174's PU name.

LUGROUP specifies the name of the model LU group (LUGRP) that VTAM uses to select a model LU definition when dynamically defining a logical unit attached through this 3174.

LUSEED provides a pattern name (L3174### in this sample) that is used to create an LU name for the dynamically created LU definition statements.

*  =====&gt; BEGINNING OF DATA SET A01LSNA
***********************************************************************
*  A01LSNA -  VTAM LOCAL SNA MAJOR NODE  -  LOCAL SNA 3174            *
***********************************************************************
* 3174 LOCAL SNA PU                                                   *
***********************************************************************
A01LSNA  VBUILD TYPE=LOCAL
PU3174   PU    CUADDR=7A0,        ** CHANNEL UNIT ADDRESS           ** X
               DLOGMOD=D4A32784,  ** DEFAULT LOGON MODE TABLE ENTRY ** X
               LUGROUP=LUGRP,     ** SDDLU GROUP - SEE A01LUGRP     ** X
               LUSEED=L3174###,   ** LU PATTERN NAME                ** X
               MAXBFRU=15,        ** RECEIVE DATA BUFFER SIZE       ** X
               USSTAB=AUSSTAB     ** USS TABLE NAME                 **
*  =====&gt; END OF DATA SET A01LSNA