You can define a group of LU 6.2 applications that provide the same function to be known and accessed by a single generic name. LUs can initiate sessions using the generic name; VTAM® determines which application program is used to establish the session. The LU knows the application program by its generic name only. This function enables VTAM to provide workload balancing by distributing incoming session initiations among a number of identical application programs, instead of overwhelming one application program.
Applications establish an association with a generic resource name after OPEN ACB and before SETLOGON OPTCD=START by issuing SETLOGON OPTCD=GNAMEADD. This association allows the application to be known by its generic resource name. An LU 6.2 application can request VTAM to use its generic name or its application network name for a particular session with an LU by specifying NAMEUSE=GNAME|APNAME on any APPCCMD macroinstruction that causes a session to be started. The application program can terminate this association with the generic resource name by issuing SETLOGON OPTCD=GNAMEDEL.
VTAM keeps track of the identity of the LU and the identity of the application that is acting as the generic resource for this session. This ensures that all subsequent session initiations from an LU that is in session with a generic resource resolve to the same application program. In this regard, the LU is said to have an "affinity" with the application.
For more information about this function, refer to z/OS Communications Server: SNA Network Implementation Guide or z/OS Communications Server: SNA Programming.