If communication is to be established between two OpenTP1 systems, you can extend transaction processing between the systems. If communication is to be established between an OpenTP1 system and a non-OpenTP1 system, you can extend transaction processing between the systems by using OSI TP.

To perform client/server communications using OSI TP, you must create an SPP for identifying association establishment and release. This is called a communication event processing SPP. By creating a communication event processing SPP, you can receive an association release notification event by the SPP. By receiving such a communication event, you can determine the timing of association re-establishment. You use the dc_xat_connect function to re-establish association.

Communication events are always reported, regardless of whether the local system is the calling system or the called system. The communication event processing SPP enables you to determine from the details of a notification event the association's attributes and status.

You must specify in advance in the XATMI communication service definition the service group name and service name of the communication event processing SPP. Communication events are reported on the basis of these specifications.

For details about the communication event processing SPP and the events that can be received, see the OpenTP1 Programming Guide and the applicable OpenTP1 Programming Reference manual.

The following figure provides an overview of a communication event processing SPP.

Figure 3-61 Overview of a communication event processing SPP