The present disclosure relates generally to communication systems and more particularly to Digital Subscriber Line (DSL) and wireless communication systems. One embodiment relates to a method of processing data in a communication system. In this method, a data stream is received by a transmitter and packaged into discrete data units prior to transmission. The size of a data unit depends upon the details of the embodiment, and is estimated by communication system prior to data transmission. Once a data unit is transmitted from the transmitter to the receiver, the receiver sends an acknowledgement that the data unit is received. Knowledge of the roundtrip time delay between transmission of the data unit and reception of the acknowledgement allows the communication system to determine an optimum data unit size to maximize throughput. Other methods and systems are also disclosed.