  In this paper, we consider the Byzantine reliable broadcast problem on
authenticated and partially connected networks. The state-of-the-art method to
solve this problem consists in combining two algorithms from the literature.
Handling asynchrony and faulty senders is typically done thanks to Gabriel
Bracha's authenticated double-echo broadcast protocol, which assumes an
asynchronous fully connected network. Danny Dolev's algorithm can then be used
to provide reliable communications between processes in the global fault model,
where up to f processes among N can be faulty in a communication network that
is at least 2f+1-connected. Following recent works that showed that Dolev's
protocol can be made more practical thanks to several optimizations, we show
that the state-of-the-art methods to solve our problem can be optimized thanks
to layer-specific and cross-layer optimizations. Our simulations with the
Omnet++ network simulator show that these optimizations can be efficiently
combined to decrease the total amount of information transmitted or the
protocol's latency (e.g., respectively, -25% and -50% with a 16B payload, N=31
and f=4) compared to the state-of-the-art combination of Bracha's and Dolev's
protocols.
