The setting of the CDRSCTI start option controls the amount of time that a dynamic CDRSC is retained by VTAM® after its last session ends. If a dynamic CDRSC has been freed by VTAM in a combined environment, search requests originating in the subarea network or in the domain of the interchange node itself can result in unnecessary broadcasts to locate a subarea resource in the APPN network.

Therefore, to reduce broadcast searches of an APPN network that does not have a central directory server, you can increase the CDRSCTI value from the default of eight minutes to as much as seven days at each interchange node. This will minimize the potential for unnecessary broadcasts of the APPN network, because dynamic CDRSCs are retained for a longer period of time after the last session ends and VTAM has more of an opportunity to take advantage of priority routing to locate the resource in the subarea network.