Specifying timeout values for locating cross-domain resources

The following start options also affect VTAM® processing in a multiple-domain subarea network:

CDRSCTI start option

In a multiple-domain environment, you define resources that are controlled by a VTAM in another domain using a cross-domain resource (CDRSC) definition statement. However, if you do not code the CDRSC definition statement, you can specify that a CDRSC definition be dynamically created by using the CDRSC=OPT operand on the cross-domain resource manager (CDRM) definition statement that defines that VTAM. If your VTAM dynamically defines a cross-domain resource, that dynamic definition can be retained by VTAM for a user-specified period of time or deleted immediately after the last session for that cross-domain resource terminates. The cross-domain resource timeout value (CDRSCTI) start option determines the processing VTAM uses for dynamic cross-domain resources. The value of this start option specifies the amount of time that VTAM is to retain the control blocks for a dynamic cross-domain resource after all sessions with that resource are terminated. For more information, see Dynamic definition of cross-domain resources.

IOPURGE start option

During cross-domain session initiation, a CDINIT is sent to the adjacent node that is most likely to be the resource owner. If a positive response is received, session setup continues with that adjacent SSCP. If a negative response is received indicating the resource was not found, the next adjacent SSCP that potentially owns the resource is obtained from the adjacent SSCP table and a CDINIT is sent to it. This continues until the resource is either found or the adjacent SSCP table is exhausted.

A situation could arise where the adjacent SSCP that was queried has a critical failure and cannot respond. In this case, the node that is trying to initiate the session waits forever for a reply (IOPURGE=0, the default), possibly blocking any future attempt to find the resource. Because the failing SSCP may not be the resource owner, the resource may be available and could be found if the search was allowed to continue through the adjacent SSCP table.

The IOPURGE start option can be used to specify how long VTAM will wait for a response before continuing a search. After a specified time interval, if a response has not been received, VTAM continues its search through the adjacent SSCP table until it either finds the resource or the table has been exhausted.