Switch Operation

Switches look very similar to hubs although there is a vast difference in its functionality.
Computer A transmits a frame.
The switch receives the frame into a port buffer and obtains the destination MAC address from the Ethernet frame.
The switch uses its MAC address table to look up the port connected to the destination MAC address.
The switch uses its high-speed backplane to send the frame out on port 4 for computer B to receive by creating a temporary virtual circuit.
None of the other connected devices see any activity on the network while this takes place.
Therefore these devices are able to transmit and receive at the same time.
The port buffer holds frames until they can be processed.