Understanding Layer 2 Switch and Layer 3 Switch: What’s the Difference? 01/04/2023 – Posted in: Network – Tags: IP addresses, layer 2 switch, layer 3 switch, MAC addresses, network topology, routing functions

In computer networking, switches play a vital role in connecting devices within a local area network (LAN). A switch is a networking device that forwards data packets between network segments. There are two types of switches: layer 2 switches and layer 3 switches. In this article, we’ll discuss the difference between the two types of switches and how they work.

Layer 2 Switch

A layer 2 switch operates at the data link layer of the OSI model and uses MAC addresses to forward data packets. When a data packet arrives at a layer 2 switch, it reads the MAC address of the source and destination devices and stores them in a forwarding table. The forwarding table contains information about which port a particular MAC address is connected to. The switch then forwards the data packet to the appropriate port based on the destination MAC address.

A layer 2 switch is ideal for small to medium-sized networks where the network topology is relatively simple. It is also useful in networks where there is a need to segment network traffic into smaller broadcast domains. However, a layer 2 switch does not perform any routing functions and cannot route data packets between different networks.

Layer 3 Switch

A layer 3 switch operates at the network layer of the OSI model and uses IP addresses to forward data packets. When a data packet arrives at a layer 3 switch, it reads the IP address of the source and destination devices and stores them in a routing table. The routing table contains information about which port a particular IP address is connected to and which network it belongs to. The switch then forwards the data packet to the appropriate port based on the destination IP address.

A layer 3 switch is ideal for larger networks where there is a need to route data packets between different networks. It can perform basic routing functions and can be used as a router in smaller networks. A layer 3 switch can also be used to segment network traffic into smaller broadcast domains like a layer 2 switch.

Difference between Layer 2 Switch and Layer 3 Switch The main difference between a layer 2 switch and a layer 3 switch is that a layer 2 switch forwards data packets based on MAC addresses, while a layer 3 switch forwards data packets based on IP addresses. Layer 2 switches are simpler and less expensive than layer 3 switches. They are ideal for small to medium-sized networks with a relatively simple network topology. Layer 3 switches, on the other hand, are more expensive and are ideal for larger networks with a more complex network topology.

Layer 2 switches operate at a lower level of the OSI model than layer 3 switches. As a result, they are faster and have lower latency than layer 3 switches. Layer 3 switches can perform basic routing functions, while layer 2 switches cannot.

In summary, a layer 2 switch is ideal for small to medium-sized networks with a relatively simple network topology, while a layer 3 switch is ideal for larger networks with a more complex network topology. Both types of switches have their advantages and disadvantages and should be chosen based on the specific requirements of the network.