Abstract: Methods and apparatuses are provided to check the order, continuity and correctness for the data segments in a test message received via a network by a terminal. The test message contains a non-repeating data pattern in which any small portion of a known length is sufficient to generate the remainder of the message. To check the order and continuity of a pair of data segments, the receiving terminal needs to check only the beginning portion of the trailing segment against the ending portion of the preceding segment, thus improving the efficiency.

Abstract: A method and system for controlling the retransmission of data packets which monitors the successive progression of cycles of round trips of message signal transmissions between a transmitter and at least one receiver for avoiding unnecessary retransmissions of data packets which are detected as incorrect during the transmission of sequentially numbered data packets of a data file. Data representative of the progress of cycles are included in the data fields of message signals transmitted to communication devices. Another copy of a data packet is not retransmitted pursuant to a request for retransmission unless the data values related to cycle progression indicate that the last transmitted copy of the data packet was not in transit to the communication device requesting the retransmission at the time the device issued the request.