The move from the shared to the switched bus was powered by the need for greater routing speeds. Switching moves a packet from an input port to an output port. This can be accomplished through a variety of methods. On a traditional general-purpose computer, switching is accomplished in memory. This is actually also practical to an extent in high-speed routers.
Packets travel across the grid from an input port, then down the grid to an output port.
This type of arrangement is also often using in ATM switching cells. The routing processor is often called the network processor. Currently, greater and greater numbers of people are using the Internet, and using it to do a much wider variety of tasks. This means an increased amount of traffic, using a much greater bandwidth. Thus, increasing router performance is crucial to handling greater bandwidths.