Network switch

A network switch is a special kind of networking hardware that helps connect different devices, like computers and printers, on a computer network. It sends information quickly to the right device.

A network switch has many ports where you can plug in devices. It uses special numbers called MAC addresses to know which device is connected to each port. This way, it can send information only to the device that needs it. This makes the network faster and more efficient.

The first device like this, called a MAC Bridge, was invented in 1983 by an engineer named Mark Kempf who worked at Digital Equipment Corporation. Since then, many companies have made switches that help networks work better. Unlike older devices called repeater hubs, a network switch makes sure information goes only where it is needed. Switches are very common today and are important for keeping our networks running smoothly.

Overview

A switch is a device in a computer network that connects other devices together. You plug many data cables into a switch to help devices talk to each other. Switches are smarter than devices called hubs. They can send information only to the right device. This makes the network faster and more secure.

An Ethernet switch works at a special level called the data link layer. It makes sure that when one device sends information, it does not mix up with information from other devices. This helps computers share the network without getting in each other's way. Switches are important in most modern networks, in big offices or small home setups. Many switches can also connect to different types of cables, such as fiber optic cables.

Role in a network

Switches connect devices on a computer network. They are often placed at the edge of a network to link computers and other devices together. In larger networks, switches can connect to other switches inside the network.

Switches can have different types of connections, such as Ethernet, to work with many kinds of networks. Some switches can also help connect different kinds of networks. They can support tools for checking network safety and performance. Modern switches can even power devices like phones or wireless points, so those devices do not need their own power supply.

In the late 1980s, the first multiport Ethernet switch was introduced by Kalpana.

Bridging

Modern network switches mainly use Ethernet connections. They connect many devices by using something called layer-2 bridging.

A device at layer 2 uses special addresses called MAC addresses to send data. It learns these addresses and keeps a list to know which device is connected to which port.

Bridges can change the speed of data to match different devices. Some fast switches can start sending data before they finish receiving it, which makes things quicker.

Links between switches follow rules set by the Spanning Tree Protocol to avoid loops. Other methods like Shortest path bridging and TRILL let multiple paths be used at the same time.

Types

Form factors

Switches come in many shapes and sizes. You can find small ones for home or office use, bigger ones for special equipment cabinets, and special ones for industrial places. Some switches can be stacked together for larger networks.

Configuration options

• Unmanaged switches are the simplest type. You just plug them in and they work. They are usually the cheapest and are often used in small offices or homes. They can be desktop or rack mounted.
• Managed switches have extra features. You can control them using special commands, a web browser, or remote management tools.
• Smart switches are a middle option. They have some management features, usually through a web browser, but not as many as full managed switches.
• Enterprise managed switches have the most features and are used in bigger networks. They are more expensive but offer the most control.

Typical management features

These features help control and monitor the switch, such as turning ports on or off, setting up better connections, and keeping track of network health.

Traffic monitoring

It can be hard to watch the data moving through a network switch because only the ports sending or receiving the data can see it.

There are special ways to help watch this data. One way is called port mirroring. In this way, the switch sends copies of the data from one port to another special port so we can see it. There are also other methods like RMON and sFlow, but these are not usually found on simple home switches. Sometimes people use a special device called a network tap to watch the data instead.