  We consider the problem of maximizing the throughput of Byzantine consensus,
when communication links have finite capacity. Byzantine consensus is a
classical problem in distributed computing. In existing literature, the
communication links are implicitly assumed to have infinite capacity. The
problem changes significantly when the capacity of links is finite. We define
the throughput and capacity of consensus, and identify upper bound of
achievable consensus throughput. We propose an algorithm that achieves
consensus capacity in complete four-node networks with at most 1 failure with
arbitrary distribution of link capacities.
