A network hub or repeater hub is a device for connecting multiple devices together and thus making them act as a single network segment.

Most hubs come with a BNC and AUI connector to allow connection to legacy 10BASE2 or 10BASE5 network segments.

Hubs do not manage any of the traffic that comes through them, and any packet entering any port is broadcast out on every other port. Since every packet is being sent out through every other port, packet collisions result—which greatly impedes the smooth flow of traffic.

Different types of hubs:

1. Passive (A hub which does not need an external power source, because it does not regenerate the signal and therefore falls as part of the cable, with respect to maximum cable lengths)

2. Active (A hub which regenerates the signal and therefore needs an external power supply)

3. Intelligent (A hub which provides error detection (e.g. excessive collisions) and also does what an active hub does)