Data communication apparatus and method

A data communication apparatus having a message receiver, and a message transmitter to transmit messages to the message receiver. The message transmitter being configured to partition a payload greater than a predetermined size into a set of plural successive messages each being no larger than the predetermined size and to associate one or more flags with respective ones of the set of plural successive messages, the one or more flags indicating an ordering of messages within a set of plural successive messages, and the message receiver having a buffer to buffer received messages of a set of plural successive messages to reassemble a payload represented by the given set of plural successive messages, and a detector to detect an expected ordering of the one or more flags with respect to receipt by the message receiver of messages of a given set of plural successive messages.