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What is a Network Switch, and How Does It Work?



Discover the definition of network switches, their functions, and the available types. Explore the unique features that distinguish switches from routers and hubs. This blog will show you what a network switch is.

A network switch is fundamental for modern networks, especially for any enterprise. Its primary function is connecting devices within a local area network (LAN), enabling sharing of resources such as business applications, multimedia messages, and essential data. The network switch has become crucial in delivering these services to end-users worldwide. In technical terms, a network switch is also called an Ethernet switch. In this blog, we will explore what is a network switch, its role in modern networks.


What is a Network Switch?


If you're new to switching networking, you might wonder, "What is a network switch?" Simply put, a network switch is a device that enables multiple IT devices to communicate with each other over a network. This communication happens through the exchange of data packets. A primary switch forwards these packets from one device to another while other network devices handle more advanced operations. Network switches can be physical appliances or components of other networking equipment, such as routers or wireless access points(APs).


Switches operate at the OSI model's Data Link layer(Layer 2) and also can be worked in the Network layer(Layer 3), which organizes and structures data for transmission over the network. They use a unique MAC address identifier to determine where to send each incoming message frame. Switches keep track of a database that correlates every MAC address to the corresponding port where the address is received, enabling quick and effective communication.


A network switch is critical in sharing IT resources such as computing power, printing, file storage, and internet access across the network. It acts as a traffic controller, directing data packets to their intended destination while ensuring efficient communication between devices.


What is The Value of Network Switches?


Network switches can connect various endpoints and offer several benefits to IT networks. They provide a wired connection to desktops, wireless access points, printers, industrial machinery, and some IoT devices and connect physical servers and storage infrastructure. With Power over Ethernet(PoE) technology, modern PoE switches can even deliver power to network devices, such as security cameras, voice-over IP phones, and sensors. Moreover, switches can collect data from IoT devices and use it for machine learning algorithms to optimize brighter surroundings.


One of the main functions of advanced switches is the ability to create virtual networks, which can isolate groups of networked systems from one another while securely segmenting specific systems from the rest, enabling the connection of large numbers of systems to a single physical network, which is common in multi-tenant data centers and large enterprises. The switches' problem-solving capabilities extend beyond simple LAN interconnection and can support thousands of devices through different network segments. With network topology, switches can be connected in various ways to support still more devices and offer full-duplex communication while boosting network performance.


The value of network switches is immeasurable in IT networks. They are problem solvers that provide wired connections to endpoints, support virtual networks, and connect multiple network segments to help thousands of devices. With their capabilities, switches enhance the efficiency and security of modern data networks and offer a plethora of benefits.


How Does a Network Switch Work?


A network switch works to transmit data from one location to another within a network. Various types of switches are used in networking, including edge switches, aggregation switches, and core switches.


When a data frame is forwarded to a MAC address that the switch is unfamiliar with, it is flooded to all ports in the switching domain, including broadcast, unknown unicast, and multicast flooding. This feature makes the switch a Layer 2 device in the OSI communications model.


In some data centers, a spine-leaf architecture is used where servers and storage connect to leaf switches, and every leaf switch connects to two or more spine switches. This setup reduces latency by decreasing the hops data takes from source to destination.


Network switches provide additional Ethernet ports for connecting to Gigabit Ethernet for small businesses and home networking. However, not all networks use switches. Some networks may be linked by bus, hub, or repeater or composed of token rings.


When a switch is connected to a device, it notes its MAC address, which identifies the physical device and remains constant. The switch identifies each device's packets by their individual MAC addresses and transmits those packets to where they should go.


Switches can also operate at Layer 3, which is necessary for supporting virtual LANs (VLANs), current layer-3 switches generally divide layer 2 networks and implement layer 2 switching through VLANs, and at the same time can realize Layer 3 IP mutual access between different VLANs.


Various Types of Switches


This section will introduce several different types of switches:


Virtual Switches are switches that exist solely as software within virtual machine hosting environments,


Routing Switches link local area networks, executing MAC-based Layer 2 switching and routing functions at the network layer (OSI Layer 3). This directs traffic according to the IP address found in each packet.


Managed Switches ports can be adjusted by the user, facilitating monitoring and configuration adjustments.


Unmanaged Switches allow Ethernet devices to transfer data automatically via auto-negotiation, which determines factors like data rate. The configuration is unchangeable and preset.


Smart Switches may be customized to permit greater control over data transmissions, though they have certain limitations compared to managed switches. They're also referred to as partially managed switches.


Stackable Switches are immovable switches that can be interconnected via a backplane cable interface to create a unified logical switch from two or more physical switches.


Modular Switches are switching cards for modular or chassis-based switches that can be inserted into a reasonably large, non-moving chassis that accommodates two or more cards. Since switch interfaces may be altered as needed, this switch offers the most flexibility and upgradability.


KVM Switches are usually employed in data centers or other locations with many servers. It provides Keyboard, Video (monitor), and Mouse connections to multiple computers, enabling users to manage a group of services through a single location or a console port.



Application of Switches in Networking


Network switches are crucial components in establishing and maintaining network connections. The upcoming examples will showcase various scenarios where switches are employed in a network.


Firstly, switches automate link connections, ensuring effective connectivity, speed, and user-friendly experience without the need for manual configurations. Secondly, switches enhance network security and reliability by providing control over data transfer. Thirdly, when connecting different network devices physically, switches with multiple front ports, typically RJ-45 ports, are essential. The number of available ports may vary. Additionally, switches operate in full-duplex mode, enabling simultaneous data transmission and reception, significantly boosting network speed compared to hubs. They are especially beneficial for home networks and situations that require regular high-powered streaming services, ensuring a reliable way to stream or play 4K videos. Lastly, switches maintain a list of unique MAC addresses for each connected device, efficiently routing network communication to the intended destination and avoiding unnecessary broadcasting to all devices, thereby reducing collisions and eliminating broadcast domains.





By reading this article, you will gain an understanding of what is a network switch and how it functions. When making a decision, it's important to consider whether a switch or router is appropriate. Switches operate at the data link layer (Layer 2) and enable resource sharing on a single LAN, while routers operate at the network layer (Layer 3) and transport data between multiple networks by analyzing IP addresses. Click here to learn more about the differences between switches and routers. To obtain further details about what is a network switch, please contact QSFPTEK CCIE/HCIE through sales@qsfptek.com or live chat for quick assistance.


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