What is a Switch in a Computer Network?

February 13, 2023 • Shannon Flynn


Today’s computer networks are essentially a group of interconnected devices that use multiple paths to send and receive data or media. Computer networks also include devices or mediums that help two different devices communicate, called network devices.

Some common network devices you’ve probably seen are routers, hubs and bridges. Routers are the network’s central point of contact for connected devices, hubs broadcast data to all devices and bridges connect two network segments. Another essential component of a modern computer network is a switch. What is a switch in a computer network, and why are they important?

What is a Switch?

In simple terms, a switch is a small piece of equipment that connects digital devices, allowing them to communicate with each other through data packets. Switches come in two forms: hardware devices that manage physical networks or software-based virtual devices. 

Switches play an essential role in computer networking. They offer wired connections for various devices, including desktop computers, the Internet of Things (IoT), industrial machinery and wireless access points. Network switches also carry a vast amount of traffic within telecommunications provider networks.

Before broadband routers became popular, standalone ethernet switch devices were common on home networks. Today, computer networks have routers, which integrate ethernet switches into the unit as a core function. In the business world, high-performance ethernet switches are still ubiquitous in corporate networking and data centers.

Types of Switches in Computer Networks

A switch in a computer network varies in size based on two factors. Their sizes depend on how many devices you need to connect in one area and how much bandwidth or network speed is required.

Here are some of the most common types of switches in computer networks:

  • Managed switch
  • Unmanaged switch
  • KVM (keyboard, video and mouse) switch
  • Smart switch
  • PoE (power over ethernet) switch

Additionally, there are three ways to deploy a network switch:

  • Core switches: These switches are essentially the backbone of the computer network. 
  • Edge/access switches: These switches manage traffic coming in and out of the network, usually from computers or access points.
  • Aggregation/distribution switches: These switches are placed in a middle layer, allowing edge switches to connect and send traffic between switches or directly to the core switch.

Switches usually operate on layer 2, also referred to as the Data Link layer, of a network of the OSI (Open System Interconnection) model. However, switches can also operate on the network’s third layer, where routing takes place.

Different types of network switches exist to meet the needs of users on the network. Small businesses might not require an advanced, high-performing switch. In contrast, large, global companies rely on them for stable network connections —  downtime is extremely costly if their network fails to operate properly. 

If you use a home computer network most of the time, your router likely has three or four built-in ethernet ports, and most of your devices use wifi. Therefore, you might not need a network switch.

How Does a Network Switch Work?

First, when devices connect to a switch, it notes its MAC address, short for media access control address. A MAC address is a unique code belonging to the device’s network interface card (NIC). Then, the NIC will attach to the ethernet cable and connect to the switch.

Through this configuration, the switch identifies the device’s outgoing packets and determines where they should be delivered. MAC addresses identify the physical device and remain unchanged, whereas the network layer 3 IP address is assigned to the device and can change over time. Here’s a good way to understand this: a device’s MAC address is a car’s VIN and a device’s IP address is a car’s license plate.

Once a packet enters the network switch, the switch reads it, matches it to one or more destination addresses and sends it through the necessary ports to deliver the packet to the correct devices.

Because there’s an increasing amount of traffic on a modern network, many switches come with full-duplex functionality, meaning that data packets received and sent to devices can access the full bandwidth of the switch’s connection. Essentially, a full-duplex switch can send and receive packets simultaneously, preventing collisions between network traffic. 

Switches: Key Building Blocks of Computer Networks

Switches in a computer network are essential for modern businesses but might not be necessary for the average consumer. Their capabilities allow further wireless connectivity, support smart devices and enable companies to utilize the Internet of Things (IoT). Switches will likely remain valuable components in network architecture as they deliver data to and from devices in the same building or across the world.