Consider a SAW ARQ system between two nodes: A (transmitting node) and B (receiving node). Assume that data frames are all of the same length and require τ seconds for transmission. Acknowledgement frames require R seconds for transmission, and there is a propagation delay P on the link (in both directions).
One in every three frames that A sends is in error at B. B responds to this with a NAK, and this erroneous frame is received correctly in the (first) retransmission by A. Assume that nodes send new data packets and acknowledgements as fast as possible, subject to the rules of stop and wait. What is the rate of information transfer in frames/second from A to B?