Specifying levels of support

RNR support is specified in the DFSDCxxx PROCLIB member by indicating RNR=ARNR, RNR=NRNR, or RNR=NONE. ARNR activates RNR and specifies that a basic session reconnect will be performed automatically by IMS during the /START DC process following an IMS or VTAM® restart. NRNR specifies that automatic session reconnect will be activated, but not used unless overridden by the logon descriptor or the logon user exit routine. Unless overridden, the session will be terminated following restart of IMS or VTAM. NONE will not activate RNR at all.

If RNR is specified without a parameter (RNR= without ARNR or NRNR), NRNR is the default. If RNR is not specified at all (no RNR=), RNR will not be activated just as if RNR=NONE was specified.

RNR support can also be indicated on the ETO logon descriptor using the OPTIONS= ARNR|NRNR parameter. The RNR support specified at this level overrides that set at the system level using IMS execution parameters. If IMS was initialized with RNR unspecified, then specification of RNR support on the ETO logon descriptor is ignored.

RNR support can be indicated on the Logon exit routine (DFSLGNX0) using the LGOPT=LGOARNR parameter. The RNR support specified at this level overrides that set using the ETO logon descriptor or the system level execution parameters. If IMS was initialized with RNR unspecified, then specification of RNR support on DFSLGNX0 is ignored.

Using the DFSDCxxx PROCLIB member, you can also specify the maximum time for session persistence following an IMS or VTAM failure. The parameter for specifying this time is PSTIMER. PSTIMER can be set from 1 to 86400 seconds. The default setting is 3600 (1 hour). If 0 is indicated, then no timer is used and session persistence will continue indefinitely.