Application termination

There is a field in the RPL extension called RPL6LAST. This field is completed by APPC/VTAM when it schedules the ATTN(LOSS) exit. RPL6LAST is a 2–bit field that indicates whether the session being terminated is:

Not the last session to this LU for this particular modename. (Other sessions remain active for this modename.)
The last session to this LU for this particular modename.
The last session to this LU for all non-control mode modenames. (SNASVCMG and CPSVCMG are control modes).
The last session to this LU for all modenames.

The safest way to terminate an application is to perform the following tasks:

Issue an APPCCMD (DEFINE) to set session limits to 0 for all modes. This stops a CNOS from the partner from starting sessions successfully.
Issue an APPCCMD (CNOS, ALL) to set session limits to 0 for all non-control mode modenames.
When RPL6LAST indicates all non-control mode sessions are ended, issue an APPCCMD (CNOS) to set SNASVCMG session limits to 0.
Repeat these steps for all partner LUs.
When RPL6LAST indicates all sessions are ended for all LUs, CLOSE the ACB.