What is the difference between a router and switches?

Some MLS's are also able to route between VLAN and/or ports like a common router. The routing is normally as quick as switching (at wirespeed). According to Cisco, Level 3 switches are basically routers that switch based on Layer 3 information, the basic difference being processing speed and/or the way they do the switching; Level 3 switches use ASICs/hardware instead of the CPU/software that a router would.