The simple definition
A network switch is a networking device that connects devices together on a computer network. It allows multiple devices to communicate with each other by forwarding data packets between them.
When a device, such as a computer or a printer, wants to communicate with another device on the network, it sends a data packet to the switch. The switch then examines the packet and forwards it to the appropriate device.
One of the key benefits of using a switch is that it allows for faster communication between devices. Instead of all devices communicating directly with each other, which can lead to network congestion, a switch can efficiently forward packets to the correct destination.
Switches also play an important role in network security. They can be configured to only allow certain types of traffic to pass through, and to block others. This can help to prevent unauthorized access to the network, and protect against malicious attacks.
Switches can be Layer 2 and Layer 3 Devices
A layer 2 switch and a layer 3 switch are both networking devices that are used to connect devices on a network. However, they work at different layers of the OSI (Open Systems Interconnection) model, which is a standard model used to understand how different networking protocols interact.
A layer 2 switch operates at the Data Link Layer (layer 2) of the OSI model. This layer is responsible for creating a link between network devices so that they can communicate. A layer 2 switch uses MAC (Media Access Control) addresses to forward packets between devices. It examines the MAC addresses of the devices and forwards the packet to the appropriate device based on that information.
A layer 3 switch, on the other hand, operates at the Network Layer (layer 3) of the OSI model. This layer is responsible for routing packets between different networks. A layer 3 switch uses IP (Internet Protocol) addresses to forward packets between devices. It examines the IP addresses of the devices and forwards the packet to the appropriate device based on that information.
The battle between which is better
Both devices have their place in the network, and multiple valid use cases. However, a layer 3 switch is more advanced than a layer 2 switch and it has routing capabilities, it can be considered as a router and a switch in one box, and it can route the traffic between the different VLANs and subnets in addition to the switching feature.
What is next?
We will continue using this series to identify and describe multiple Network devices. How they fit in a typical network.
Other topics, part of this series
- The Basics of Networking | Network Elements | Routers
- The Basics of Networking | Network Elements | Firewalls and NGWF
- The Basics of Networking | Network Elements | Access Points
- The Basics of Networking | Network Elements | Wireless LAN Controllers
- The Basics of Networking | Network Elements | Endpoints, Servers and Computers
About the Author:
Andres Sarmiento, CCIE # 53520
With over 18 years of professional experience, Andres is a specialist in Unified Communications and Collaboration technologies, Enterprise Networks, and Network Security. He has consulted for numerous companies in South Florida, including Financial Institutions, on behalf of Cisco Systems. Andres has played a key role in several high-profile implementations, utilizing Cisco technologies such as Data Center, UC & Collaboration, Contact Center Express, Routing & Switching, Security, and Hosted IPT Service Provider infrastructures.