OPTIMISTIC TRANSMISSION FLOW CONTROL INCLUDING RECEIVER DATA DISCARDS UPON INADEQUATE BUFFERING CONDITION

A program product for a message processing system in which messages are transmitted from source nodes to destination nodes. A transmission flow control technique is disclosed in which the source node optimistically sends control information and a data portion of a message, and wherein a destination node discards the data portion of the message if it is unable to accommodate it. The destination node, however, retains enough of the control information to identify the message to the source node, and when the destination node is subsequently able to accommodate the data portion, the destination node issues a request to the source node to retransmit the data portion of the message. Discarding of one message is followed by discards of sequential messages, until the destination node is able to accommodate the data portions of messages. The flow control technique disclosed herein is used, for example, in an environment where buffers are posted to accommodate messages at the destination node, and is particularly suited for conditions arising in multi-tasking systems where the destination node is generally assumed to be prepared to accommodate data, however, if not prepared, is likely not prepared for long periods of time.