A network switch is a small device that joins multiple computers together at a low-level network protocol layer. Technically, network switches operate at layer two (Data Link Layer) of the OSI model.
Network switches look nearly identical to hubs, but a switch generally contains more "intelligence" (and a slightly higher price tag) than a hub. Unlike hubs, network switches are capable of inspecting the data packets as they are received, determining the source and destination device of that packet, and forwarding that packet appropriately. By delivering messages only to the connected device that it was intended for, network switches conserve network bandwidth and offer generally better performance than hubs.
As with hubs, Ethernet network switches are the most common. A network switch offers differing port configurations starting with the four- and five-port models, and support 10 Mbps Ethernet, 100 Mbps Ethernet, or both.
Managed switches are different from Unmanaged switches in the fact that a managed switch offers more features in terms of layer 3 routing and traffic shaping ability.