Defining a PU and an LU for the configuration services XID exit routine

With the configuration services XID exit routine, you can give VTAM® information to create dynamic representations of switched devices without disrupting a switched network. You do not have to explicitly define a switched device to VTAM before the device attempts to dial in.

When an unknown device attempts to dial in, the following occurs:

If the device has a CPNAME, the exit checks for the device's definition in the CPNDEF definition file.
If the device has an IDBLK and IDNUM, the exit checks for the device's definition in the NIDDEF definition file.
If the device does not have a CPNAME, IDBLK, or IDNUM, or if the exit cannot find a definition for the device in CPNDEF or NIDDEF, the exit invokes a name generation function and creates the necessary PU and LU names.

Following is a sample CPNDEF definition file for the connection shown in Figure 1, where:

A81P884A is the CPNAME of the device
A81P884 is the device's physical unit name
MODELPU is the name of the appropriate physical unit model definition
A81D8841 is the device's logical unit name
MODELLU is the name of the appropriate logical unit model definition

***********************************************************************
* A81P884A:  PU AND LU NAMES
***********************************************************************
A81P884A
         A81P884
         MODELPU
         A81D8841
         MODELLU
***********************************************************************

For a sample NIDDEF file, as well as another sample CPNDEF file, see z/OS Communications Server: SNA Customization.