A switch is a network device that selects a path or circuit for sending a data unit its next destination. In smaller network a switch is not required. It is required in large internetwork, where there can be multiple way of transmitting a massage from a sender to a destination. The purpose of switches is to select the best possible path. Switches use a feature called address storing, which checks the destination for each data packet and send it directly to the computer.
Comparison of hubs and switches
1) Band width: Divides by total number of ports in use. Dedicated to each port in use.
2) Data transmission: Broad cast to all connected computers. Broad cast only to receiving computer.
3) Duplex support Half duplex. Full duplex when used with full duplex NIC’s.