Too Long; Didn't Read
A Layer 3 switch combines the functionality of a switch and a router. It acts as a switch to connect devices that are on the same subnet or virtual LAN at lightning speed. It can support routing protocols, inspect incoming packets, and may even make routing decisions supporting source and destination addresses. Layer 3 switches were originally designed to improve routing performance in large networks, especially corporate intranets. They are most applicable only for large intranet environments with many device traffic and many traffic volume.