Full utilization, fairness and bounded access delay on high speed bus networks

The purpose of this paper is to understand the relationship between utilization, fairness and access delay in high speed slotted bus networks. We illustrate this relationship by means of a protocol called FUFA (fully utilized and fair). We define full utilization, and fairness precisely, and show that both are achieved together in the FUFA protocol. In addition, the protocol provides bounded access delay that is linear in the round trip propagation delay, and at most a constant away from its minimum possible value for any bus protocol that is both fully utilized and fair. The main idea is that each station takes account of the idle slots propagated previously to interpret the information from downstream (i.e., estimated aggregate number of data segments in the queue downstream and estimated number of active downstream stations). This allows the active downstream stations to be served in a round robin fashion according to the updated information.