A network device joining many systems together at a low-level layer of the network protocol. The most widely used Ethernet switches operate at the second layer (Data Link Layer) of the OSI model and look like hubs. Switches have more “intelligence” than hubs, however, and are therefore more costly. Unlike hubs, switches can inspect data packets as they are received, they can determine both the source and the destination device of the packet, and they can then forward the packet correctly. By delivering messages to only the connected device for which it was intended, network switches save network bandwidth and offer typically better performance than hubs can.

Network switches offer varying port configurations, beginning with 4-port or 5-port models and going up to stackable core infrastructure switches with several hundred ports. They support 10 Mbps Ethernet, 100 Mbps Ethernet, and 1GBit/s Ethernet, or all three.

See Also: Ethernet; Open Systems Interconnect (OSI) Model; Protocol.