Method for transmitting data via a network

A communication controller at the sending computer divides data transferred from a host into sub-ACK unit packets, and transfers them sequentially to a destination without waiting for the sub-ACK's being subsequently provided by the destination. A communication controller at the receiving computer issues a sub-ACK to the sending computer for each of the sub-ACK unit packet, if the sub-ACK packet has been normally received and otherwise issues retransmission request for the sub-ACK unit packets and merges data included in the sub-ACK unit packets into the initial data, after they are normally received.