Hub is a network device used for directly connecting computers. It acts as a center for LAN. It can be considered a multi-port repeater.

Hub works on the physical layer. It receives bits and sends them to all the devices connected to it (flooding strategy). It has no routing table, it can't filter data. When bits reach a device, the device checks their destination address and matches it to its own MAC address.

If 2 devices send data simultaneously, collision occurs and data gets lost. Devices then have to wait a certain amount of time to try again.

The transmission mode is half-duplex.