  Today's practical, high performance Byzantine Fault Tolerant (BFT) consensus
protocols operate in the partial synchrony model. However, existing protocols
are inefficient when deployments are indeed partially synchronous. They deliver
either low latency during fault-free, synchronous periods (good intervals) or
robust recovery from events that interrupt progress (blips). At one end,
traditional, view-based BFT protocols optimize for latency during good
intervals, but, when blips occur, can suffer from performance degradation
(hangovers) that can last beyond the return of a good interval. At the other
end, modern DAG-based BFT protocols recover more gracefully from blips, but
exhibit lackluster latency during good intervals. To close the gap, this work
presents Motorway, a novel high-throughput BFT protocol that offers both low
latency and seamless recovery from blips. By combining a highly parallel
asynchronous data dissemination layer with a low-latency, partially synchronous
consensus mechanism, Motorway (i) avoids the hangovers incurred by traditional
BFT protocols and (ii) matches the throughput of state of the art DAG-based BFT
protocols while cutting their latency in half, matching the latency of
traditional BFT protocols.
