A Sync Point implementation that knows the names of all the transactions that can be supported (for example, through configuration of the gateway) may accept incoming Sync Point conversations by issuing a RECEIVE_ALLOCATE verb specifying the name of the transaction and indicating that it is willing to accept Sync Point conversations.
The RECEIVE_ALLOCATE verb was modified to allow a TP to specify that it can accept Sync Point conversations by adding a new syncpoint_rqd field to the VCB. When this field is set to AP_YES it indicates that the transaction program can accept Sync Point conversations from SNA Server. When this field is set to AP_NO (the default), it indicates that Sync Point conversations are not supported.