A Starvation-Free Access Protocol for a Full-Duplex Buffer Insertion Ring Local Area Network

for a Full-duplex Bu er Insertion Ring Local Area Network RAHUL SIMHA1 Dept. of Computer Science College of William & Mary Williamsburg, VA 23185 YORAM OFEK IBM Research Division TJ Watson Research Center Yorktown Heights, NY 10598 Abstract Of several existing designs for Local Area Networks, the Bu er Insertion Ring has been shown to provide higher throughputs, lower mean delays and greater spatial reuse than competing designs such as the Token Ring and Slotted Ring networks. However, one disadvantage is that the normally unregulated access scheme of the Insertion Ring allows for the phenomenon of \starvation" when a network node has to wait too long before it can access the ring. In our work, we demonstrate that starvation is a serious problem and present a protocol to prevent it. It is shown that the new protocol is correct, stable and does not substantially degrade the otherwise e cient operation of the ring.