Patent ID: 7158544
Filing Date: 2007-01-02
Classification: H04L,H04Q

Abstract:
1. In a data unit oriented communication between a sender and a receiver, in which the sender divides an amount of data to be sent into one or more data units, and the receiver acknowledges correct receipt of the data units by returning acknowledgment data units to the sender, a method of detecting whether an acknowledgment data unit received by the sender corresponds to an original transmission of a data unit or a retransmission of a data unit, said method comprising: for original transmissions of data units, adding a first mark by the sender to each transmitted data unit; for retransmissions of data units, adding a second, different mark by the sender to each transmitted data unit; receiving by the receiver, a data unit and a corresponding mark; adding the corresponding mark by the receiver to an acknowledgment data unit corresponding to the received data unit; sending the acknowledgment data unit from the receiver to the sender; and determining by the sender whether the data unit received by the receiver was an original transmission of the data unit or a retransmission of the data unit, based on the mark received by the sender in the acknowledgment data unit.