External router (EX)

The external router (EX) subtask receives submit requests from the data router (DX) subtask when an operation is ready to be started at a computer automatic workstation that specifies a user-defined destination ID. The external router calls the operation-initiation exit, EQQUX009, to handle communications with the user-defined destination.

The EX subtask regularly checks for new requests on the EXA queue. When a new request arrives the EX subtask builds a parameter list and calls EQQUX009. If EQQUX009 abends or is not loaded, the EX subtask creates a workstation offline event for all user-defined destinations. In this case, the status of the operation that corresponds to the request is set according to the SUBFAILACTION keyword of the JTOPTS initialization statement. Subsequent submit request on the EXA queue are discarded and the corresponding operation status is set according to the WSOFFLINE keyword of JTOPTS.

The EXA queue allows for 32000 elements. If the queue becomes full the EX subtask issues a workstation offline event for all user-defined destinations. EQQUX009 must return control to the EX subtask before any subsequent queue elements are processed by the EX subtask. If the return code from EQQUX009 is not 0, the EX subtask sets operation status or generates workstation offline events as specified in the description of the operation-initiation exit in Customization and Tuning.