What is a hub? A hub is a hardware element for centralizing network traffic from multiple hosts that also propagates the signal. It has several ports - enough to link machines to one another, usually 4, 8, 16, or 32. Its only goal is to recover binary data from a port and send it to all the other ports. The hub connects several machines, sometimes arranged in a star shape, which gives it its name because all communication from the machines on the network passes through it.