  We continue the investigation, started in [J. Stat. Phys. 166, 926-1015
(2017)], of a network of harmonic oscillators driven out of thermal equilibrium
by heat reservoirs. We study the statistics of the fluctuations of the heat
fluxes flowing between the network and the reservoirs in the nonequilibrium
steady state and in the large time limit. We prove a large deviation principle
for these fluctuations and derive the fluctuation relation satisfied by the
associated rate function.
