Which layer of the OSI model does a Layer 3 switch operate at?

A Layer 3 switch operates at the Network Layer of the OSI model. The primary function of a Layer 3 switch is to route traffic between different networks or subnets, which is a key responsibility of the Network Layer. This layer is responsible for logical addressing and routing packets across different networks.

Layer 3 switches combine the functionality of traditional switches, which operate at the Data Link Layer, with the routing capabilities found at the Network Layer. This allows them to make intelligent decisions based on IP addresses, enabling them to forward packets to the correct destination in a more advanced way than a simple Layer 2 switch, which strictly deals with MAC addresses at the Data Link Layer.

By functioning at this layer, Layer 3 switches enhance network efficiency and reduce the amount of broadcast traffic, as they can make forwarding decisions based on IP addresses rather than simply forwarding frames based on MAC addresses. This ability to route traffic while maintaining high-speed switching capabilities is a significant advantage in modern network design.