  The generation of GHZ states in quantum networks is a key element for the
realization of several quantum information tasks. Given the complexity of the
implementation of such generation, it is not easy to find an unambigous proof
for an optimal protocol. Motivated by recent improvements in NV center
manipulation, we present and compare an extensive list of protocols for
generating GHZ states using realistic parameters. Furthermore, in order to
establish the goodness of the various protocols, we test them on a specific
application, i.e. conference key agreement. We show that for an high number of
nodes the best protocol is one presented here for the first time.
