A sample configuration services XID exit routine (ISTEXCCS ASSEMBLE) is provided in the sample library (SYS1.SAMPLIB). You can write your own exit routine or use the sample. To code the exit routine to build dynamic resources, follow these steps:

1. Code the exit to supply names for:
   • The switched PU and LU resources
   • The model definition to be used for the PU or LU
   • The dynamic switched major node where the dynamic PUs and LUs are to be created
     Note: If the exit does not return a major node name, the default major node ISTDSWMN is used. If the exit returns an unknown major node name, a new dynamic switched major node will be created.
2. Install the exit routine on VTAM® to support dynamic switched devices.
3. Activate the routine using the MODIFY EXIT command; otherwise, no dynamic definitions are built, and the device request for connection is rejected.

For information about coding this exit routine, see z/OS Communications Server: SNA Customization.