concept

Hub

A node with an unusually large number of connections compared with the rest of the network. In scale-free networks the vast majority of nodes have only a few links, while a tiny minority of hubs hold most of the connections — they are the traffic junctions that keep the whole system stitched together. The existence of hubs creates the core paradox: the network is extremely robust to random damage (which almost never hits a hub) yet extremely fragile to a targeted strike aimed at the hubs.