The DRDA code is invoked based on the setting of the PROTOCOL parameter. On the application server this parameter is on the SQLSTART EXEC; on the application requester, it is on the SQLINIT EXEC. When the application server is started with PROTOCOL=AUTO, access from DB2 Server for VM and non-DB2 Server for VM application requesters is allowed. When the application requester specifies PROTOCOL(AUTO) or PROTOCOL(DRDA), connections to DB2 Server for VM and non-DB2 Server for VM application servers are allowed.
When the application server is started with PROTOCOL=AUTO and SYNCPNT=Y, distributed unit of work support is enabled. This means that the application server can participate in multiple-site read multiple-site update logical units of work. This requires DB2 Server for VM to interface with VMCRR. If SYNCPNT=N is specified, then the DB2 Server for VM server does not interface with VMCRR and the server is restricted to multiple-site read single-site update units of work. When SYNCPNT=N, the DB2 Server for VM server may be one of the multiple sites where data is only read, or it may be the single site where data is updated.
| Note: | If SYNCPNT=Y is specified but a CRR Recovery server has not been installed, distributed unit of work is not possible. Error messages are issued and DB2 Server for VM runs as if the SYNCPNT startup parameter had been set to N. |