The VTAM® application program must specify, during OPNDST processing, whether the session request is for a primary extended recovery facility (XRF) or backup XRF session. This is accomplished by using the correct parameters on the OPNDST macroinstruction command, setting the appropriate BIND indicator specifying "control vectors included", and completing the XRF session-activation control vector using the NIB BNDAREA field when OPNDST is issued.

The XRF control vector must be appended to the end of the user data field in the BIND. The control vector indicator is the BINCTLV bit in the BINCMNP2 field.

For more information concerning the structure of the XRF session-activation control vector, see XRF session activation control vector.