In our recent Physical Review Letters paper we demonstrate a novel detection scheme that provides a practical way of characterising entanglement for quantum communication networks. On the theory side, we devised a new witness of entanglement that is robust as well as scalable, meaning that it can be implemented in any number of parties, i.e. complex quantum networks. Experimentally we tested our witness for two and three parties, with different losses and with different degree of entanglement. We expect that this kind of scheme will be useful in certifying entanglement in complex long distance quantum communication networks.