Network Engineer Interview Question:

Can you explain the difference between a layer 2 and layer 3 switch, and in what scenarios would you use each?

In networking, a Layer 2 switch operates at the data link layer (Layer 2) of the OSI model and uses MAC addresses to forward traffic within a local network. It forwards packets based on the MAC address of the destination device.

On the other hand, a Layer 3 switch operates at the network layer (Layer 3) of the OSI model and can perform routing functions in addition to switching. It uses IP addresses for packet forwarding and can make routing decisions based on network layer information.

Layer 2 switches are commonly used in LAN environments to provide network connectivity at the data link layer, ensuring efficient and fast communication within the local network. They are ideal for segmenting LANs, creating VLANs, and improving network performance.

Layer 3 switches, on the other hand, are used in environments where routing capabilities are needed within the switching infrastructure. They can route traffic between different subnets or VLANs and optimize network performance by making intelligent routing decisions based on network layer information.

Ultimately, the choice between a Layer 2 and Layer 3 switch depends on the specific requirements of the network. Layer 2 switches are suitable for basic network connectivity and segmentation, while Layer 3 switches are more versatile and can handle routing functions in addition to switching.