Switch has replaced the bridge in the modern network, which is replacing routers in many instances as well. A switch is a box with multiple cable jacks in it that looks a lot like a hub. Some manufacturers have hubs and switches of various sizes that are all but identical in appearance. The difference between a hub and a switch is that while a hub forwards every incoming packet out via all ports, a switch forwards each incoming packet only to the port that offers access to the destination system.
Switches convert the LAN from a shared network medium to a dedicated one. If you have a small network that uses a switch instead of a hub, each packet takes a dedicated path from the source computer to the destination, forming a separate collision domain for those two computers. Switches forward broadcast
Messages to all ports, but not unicasts and multicasts. No systems receive packets destined for other systems, and no collisions occur during unicast transmissions. While a bridge reduces unnecessary traffic congestion
on the network, a switch all but eliminates it.
Another benefit of switching is that each pair of computers has the full bandwidth of the network dedicated to it. A standard Ethernet LAN using a hub have 20 or more computers sharing the same 10 Mbps of bandwidth. Replace the hub with a switch, and every pair of computers has its own dedicated 10 Mbps
channel. This improves the overall performance of the network without the need for any workstation modifications to it. Switches offer ports that operate in Full-duplex mode. Full-duplex operation can effectively double the throughput of a 10 Mbps network to 20 Mbps.
