CLSDST OPTCD=PASS is used to initiate a session between the SLU and a new PLU before terminating the sessions between the application program and the SLU. Use of OPTCD=PASS requires authorization for the issuing application program (AUTH=PASS on the APPL definition statement).

When OPTCD=PASS is issued, the RPLAAREA field must point to the name of the PLU with which the SLU is to have a session. The RPL's AREA field can point to up to 255 bytes of user data to be sent with the session-initiation request. The RPL's AREALEN field must contain the length of the data. This user data is passed to the new PLU in the CINIT request. If the RPL points to an NIB, the LOGMODE field in the NIB specifies a logon mode name which is used to select a set of session parameters and a class of service for the new session. The USERFLD field in the NIB, if not 0, is used as a correlator for the session-initiation request. This correlator appears in the NSEXIT exit routine parameter list, if it is scheduled with a Notify request, to indicate that the initiate procedure failed or completed successfully. If the USERFLD field in the NIB is 0, then the NSEXIT routine is scheduled with a Network Services Procedure Error (NSPE) request if the procedure fails.

OPTCD=PASS first initiates a session between the session partner in the sessions being terminated, and the new PLU. The initiate operation specifies priority queuing, so that if the SLU is at its session limit, the new session is placed at the front of the queue. Then, the sessions within the scope of CLSDST are terminated. The type of UNBIND sent by OPTCD=PASS is an UNBIND with an UNBIND SON code of BIND forthcoming. This type of UNBIND indicates that another PLU is expected to BIND a session and, therefore, the LU should not go into a mode that would reject the new session. (An example of such a mode is the IBM® 3790 Communication System offline operation mode, called local mode.)

If the SLU is at its session limit when OPTCD=PASS is issued, the queued session between the new PLU and the SLU becomes a pending active session after any of the SLU's sessions are terminated, and session establishment continues. The effect for dependent LUs is that the application program determines which session the SLU has next, even if other PLUs have been waiting longer for a session with that SLU.

The CLSDST macroinstruction can specify PARMS=(THRDPTY=NOTIFY) to indicate that the application program wants to be notified when the target session is established (that is, when a positive response is received to the BIND for that session). If this parameter is specified, and the session is established, the application program receives a Notify request in its NSEXIT routine. If the session setup fails, the application program receives an NSPE or Notify request in its NSEXIT routine, regardless of the setting of this parameter. See NSEXIT exit routine for more information about the Notify request.