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What is a network switch, and how does it work?

A network switch is an essential hardware component that connects devices together on a computer network. Switches enable networked devices, including computers, printers, servers, and more to communicate with each other by receiving and forwarding data packets to the intended destination device.

Switches operate at Layer 2 (Data Link Layer) of the OSI model, using MAC addresses to uniquely identify devices. This allows switches to maintain dedicated connections between networked devices, providing each one with full bandwidth instead of forcing them to share a common channel as hubs do.

How Does a Network Switch Work?

A network switch has multiple ports that devices plug into, usually via Ethernet cables. When a device connected to a switch sends out data, the switch determines which port the destination device is plugged into based on its MAC address.

The switch then creates a temporary connection between the two ports to relay the data directly to the recipient device only. This direct connection gives the two devices full access to the network’s bandwidth while exchanging data.

Network switch
Network switch

As soon as the data transmission is complete, the temporary connection closes, allowing the switch ports to relay data between other devices. This maximizes efficiency and enables multiple simultaneous data exchanges without interference.

Some key benefits provided by using a network switch include:

  • Dedicated bandwidth – Every connected device gets full access to the network’s bandwidth when transmitting data as opposed to sharing it. This ensures fast data speeds.
  • Enhanced security – Traffic is only sent directly between the communicating devices rather than broadcast openly as in a hub network. This makes data interception more difficult.
  • Flexible growth – Additional devices can be added easily by plugging them into open ports without affecting the other connections’ performance. This allows networks to scale out conveniently.
  • Improved manageability – Advanced switches provide features like port mirroring, link aggregation, VLANs, and more to simplify administration and monitoring.

Types of Network Switches

There are several categories of network switches available to choose from, differentiated by their capabilities:

Unmanaged Switches

These entry-level switches can be installed without any manual configuration. They automatically connect networked devices together while having limited functionality beyond relaying data packets between ports. Unmanaged switches are a plug-and-play, cost-effective choice ideal for small networks.

Unmanaged switch
Unmanaged switch

Managed Switches

These advanced switches come equipped with features to monitor, secure, optimize, troubleshoot, and control the network. Functions like VLANs, SNMP, port mirroring, and QoS allow granular administration of traffic. As a result, managed switches are deployed in large, high-performance networks and data centers. They require manual configuration to enable their capabilities fully.

Managed switch
Managed switch

Smart Switches

Smart switches provide a middle ground between unmanaged and managed switches regarding features, complexity, and pricing. They come with some basic management and monitoring capabilities through a web interface but lack extensive configurability. Smart switches meet the needs of small to medium-sized networks reasonably well.

Comparing Switches to Hubs and Routers

While a switch connects devices together on a single local area network (LAN), a router connects multiple networks to each other, usually over longer distances. Routers transmit data between different LANs, subnetworks, or wide area networks (WANs) based on their Network Layer (Layer 3) addresses.

In contrast, a network hub can only broadcast data openly to all connected devices instead of directing transmissions. This leads to collisions, slower performance, and security vulnerabilities compared to a switch.

Therefore, within a LAN, network switches are used extensively to connect devices together for efficient communication, while routers handle inter-network data routing between different LANs and WANs.

Where are Network Switches Used?

Some common applications of network switches include:

  • Connecting office computers within a LAN
  • Linking servers to a data center network
  • Expanding WiFi coverage using PoE switches
  • Building high-speed backbone networks on campuses
  • Enabling data exchange between VLANs
  • Providing server access to storage area networks (SANs)

Virtually any environment that needs networked devices to communicate with each other locally can benefit tremendously from deploying appropriately sized network switches as part of their infrastructure.

Conclusion

Network switches form the foundation of many modern networks due to their scalability, performance, and administrative control capabilities. By intelligently relaying data only between transmitting and receiving ports, switches enable the efficient flow of traffic without broadcast storms or security issues.

Choosing the right switch, whether unmanaged, managed, or smart, according to your network’s size and requirements is vital. This helps create a high-speed network fabric allowing connected devices to communicate seamlessly. Understanding switch operations and their differences from hubs and routers allows organizations to design robust networks that can handle their workloads.

References

Switch vs Hub vs Router

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-2960-x-series-switches/white_paper_c11-728551.html

OSI Model Explained

https://www.cloudflare.com/en-gb/learning/ddos/glossary/open-systems-interconnection-model-osi/

Unmanaged vs Managed Switches

https://www.researchgate.net/publication/327796012_Unmanaged_versus_Managed_Switches