You can code CDRSC definition statements (or model CDRSC definition statements) for your independent LUs and specify the adjacent link stations (PUs) that VTAM® uses to contact the independent LU. You can specify the adjacent link stations either by using the ALSLIST operand on the CDRSC definition statement, or by using the adjacent link station selection function of the session management exit routine. For more information about using the exit routine, see Dynamic selection of session connections. For more information about defining model CDRSCs, see Model definition of cross-domain resources.

CDRSC    VBUILD TYPE=CDRSC
VRCDRSC  CDRSC ALSLIST=(SWPUAIO6,SWPUA107)   ADJACENT LINK STATION NAMES
               ALSREQ=YES,                   USE ALS LIST ONLY
               LOGAPPL=APPL1,                AUTOMATIC LOGON
               DLOGMOD=DSILGMOD,             LOGON MODE TABLE ENTRY
               RESSCB=3                      SESSION CONTROL BLOCKS

ALSLIST=puname indicates to VTAM that this resource is an independent LU defined as a CDRSC. The ALSLIST operand can list one or more adjacent link stations that VTAM uses. The ALSLIST operand can also include an ISTAPNPU entry, a reserved keyword that represents any APPN capable PU. This entry can be used instead of listing each APPN adjacent link station. For information about controlling connection to independent LUs that are accessible over both LEN and APPN connections, see Establishing and controlling sessions.

You can add and delete adjacent link stations in the list of adjacent link stations using the MODIFY ALSLIST command. For more information about this command, see z/OS Communications Server: SNA Operation.

You can use the adjacent link station selection function of the session management exit routine to dynamically add other adjacent link stations to the list and to perform other adjacent link station selection functions. For details, see z/OS Communications Server: SNA Customization.