What is the difference between layer 2 and layer 3 switches?

Layer 2 and layer 3 switches are both network devices used for forwarding data packets within a local area network (LAN). However, they differ in terms of their functionality and the layer at which they operate in the OSI model.

Layer 2 switches, also known as Ethernet switches, operate at the data link layer (Layer 2) of the OSI model. Their primary function is to forward data packets based on the MAC (Media Access Control) addresses of devices connected to the network. Layer 2 switches use MAC address tables to learn and store the MAC addresses of devices connected to each of their ports. When a data packet arrives at a layer 2 switch, it examines the destination MAC address and forwards the packet only to the port associated with that MAC address. This process is known as MAC address learning and forwarding. Layer 2 switches are typically used to create LANs and segment network traffic.

On the other hand, layer 3 switches, also known as IP switches or multilayer switches, operate at both the data link layer (Layer 2) and the network layer (Layer 3) of the OSI model. In addition to forwarding data packets based on MAC addresses, layer 3 switches can also perform routing functions based on IP addresses. Layer 3 switches have the capability to maintain routing tables and make forwarding decisions based on IP addresses. They can route traffic between different VLANs (Virtual Local Area Networks) or subnets within a LAN. Layer 3 switches are commonly used in larger networks where routing between different subnets is required.

In summary, the main difference between layer 2 and layer 3 switches lies in their functionality and the layer at which they operate. Layer 2 switches forward data packets based on MAC addresses, while layer 3 switches can perform both MAC address-based forwarding and IP address-based routing. Layer 3 switches are more advanced and versatile, suitable for larger networks with multiple subnets, while layer 2 switches are simpler and primarily used for LAN segmentation.