  We investigate the physical mechanism behind the counterintuitive phenomenon,
the distribution of continuous-variable entanglement between two distant modes
by sending a third separable auxiliary mode between them. For this purpose, we
propose a new more simple and more efficient protocol resulting in distributed
entanglement with more than an order of the magnitude higher logarithmic
negativity than in the previously proposed protocol. This new protocol shows
that the distributed entanglement originates from the entanglement of one mode
and the auxiliary mode used for distribution which is first destroyed by local
correlated noises and restored subsequently by the interference of the
auxiliary mode with the second distant separable correlated mode.
