Performance of ARQ schemes on token ring networks

Token ring networks differ in the manner in which acknowledgements are handled. In Newhall rings, acknowledgements of data packets are either sent as independent packets or piggybacked on returned data packets. In acknowledgement rings, there is an acknowledgement field in each data packet. The authors present an empirical formula that predicts the average network access delay in networks where the sender is allowed to transmit only one packet each time it seizes the token and discuss its validity. The performance of the stop-and-wait ARQ (automatic-repeat-request) scheme in token ring networks is treated. The average access delay, optimum window size, and maximum achievable throughput as functions of network and protocol parameters in Newhall rings when the continuous ARW scheme is used are studied. Tradeoffs between average access delay and average buffer occupancy time are examined