An ATM Adaptation Layer for Reliable Transfers

There has been much attention given to ATM Adaptation Layers (AAL) over the ten–year history of ATM standardization. Yet none of the existing standards include a retransmission protocol to ensure reliability of the transfers. In this paper we propose an AAL for doing selective retransmissions of individual segments that have been lost or corrupted in the transfer. Since the amount of retransmitted data equals the amount lost, there is little risk of aggravating congestion and the reliability is provided as economically as possible. The protocol relies on the orderly delivery of ATM virtual circuits so that data octets can be identified uniquely by their locations in the data stream.