What are the main functions of a switch?

The main functions of the switch are physical addressing, network topology, error checking, frame sequence and flow control; the switch is a network device used for electro-optical signal forwarding, and also has some new functions such as Support for virtual LAN, support for link aggregation, and some even have firewall functions.

The operating environment of this tutorial: Windows 10 system, DELL G3 computer.

What are the main functions of the switch

The main functions of the switch include physical addressing, network topology, error checking, frame sequence and flow control. Switches also have some new functions, such as support for VLAN (Virtual LAN), support for link aggregation, and some even have firewall functions

Switch means " "Switch" is a network device used for electrical (optical) signal forwarding. It can provide an exclusive electrical signal path for any two network nodes connected to the switch. The most common switch is an Ethernet switch. Other common ones include telephone voice switches, fiber optic switches, etc.

Switching is a general term for the technology that uses manual or automatic equipment to transmit information to the corresponding route that meets the requirements according to the needs of both ends of the communication. Switches can be divided into WAN switches and LAN switches based on different working locations. A wide area switch is a device that performs information exchange functions in a communication system. It is applied at the data link layer. The switch has multiple ports, each with bridging capabilities, that can connect to a local area network or a high-performance server or workstation. In fact, switches are sometimes called multiport bridges.

A network switch is a device that expands the network and can provide more connection ports in a subnetwork to connect more computers. With the development of the communications industry and the advancement of informatization of the national economy, the network switch market has shown a steady upward trend. It is cost-effective, highly flexible, relatively simple and easy to implement. Ethernet technology has become the most important LAN networking technology today, and network switches have become the most popular switches.

Switch is the English name of the switch. This product is an upgrade of the original hub. In appearance, it is not much different from the hub. Since both ends of the communication need to transmit information, and the information to be transmitted is sent to the corresponding router that meets the required standards through equipment or manually, this technology is switch technology. From a broad perspective, the device that implements the information exchange function in a communication system is a switch.

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##Classification

Broadly speaking, network switches are divided into two types: WAN switches and LAN switches. WAN switches are mainly used in the telecommunications field to provide a basic platform for communications. LAN switches are used in local area networks to connect terminal devices, such as PCs and network printers. From the transmission medium and transmission speed, it can be divided into Ethernet switches, Fast Ethernet switches, Gigabit Ethernet switches, FDDI switches, ATM switches and Token Ring switches, etc. In terms of scale application, they can be divided into enterprise-level switches, department-level switches, and workgroup switches. The scales divided by various manufacturers are not completely consistent. Generally speaking, enterprise-level switches are all rack-mounted. Department-level switches can be rack-mounted (with fewer slots) or fixed-configuration. And workgroup switches Level switches are of fixed configuration (with relatively simple functions). On the other hand, from the perspective of application scale, when used as backbone switches, switches that support large-scale enterprise applications with more than 500 information points are enterprise-level switches, switches that support medium-sized enterprises with less than 300 information points are department-level switches, and switches that support 100 information points are department-level switches. Switches within information points are workgroup-level switches.

With the rapid development of computers and their interconnection technology (also commonly known as "network technology"), Ethernet has become the most popular short-distance two-layer computer network so far. The core component of Ethernet is the Ethernet switch.

Whether it is manual switching or program-controlled switching, it is all for transmitting voice signals and is a "circuit switching" that requires an exclusive line. Ethernet is a computer network that needs to transmit data, so it uses "packet switching". But no matter which switching method is adopted, the switch's feature of providing an "exclusive path" between two points will not change. As far as Ethernet equipment is concerned, the essential difference between a switch and a hub is that when A sends a message to B, if it passes through the hub, all network nodes connected to the hub will receive the message (that is, it will be sent in the form of a broadcast) , but the network card will filter out information that is not sent to the local machine at the hardware level; if it passes through the switch, unless A notifies the switch to broadcast, C will never receive the information sent to B (obtaining the switch control permission to monitor except).

Ethernet switch manufacturers have launched three-layer or even four-layer switches based on market demand. But in any case, its core function is still Layer 2 Ethernet packet switching, but it has a certain ability to process IP layer or even higher layer packets. A network switch is a device that expands the network and provides more connection ports in the subnetwork to connect more computers. With the development of the communications industry and the advancement of informatization of the national economy, the network switch market has shown a steady upward trend. It has the characteristics of high cost performance, high flexibility, relative simplicity and easy implementation.

Optical switch

Optical switching is the next generation switching technology being developed. All switching technologies are based on electrical signals. Even fiber optic switches first convert optical signals into electrical signals. After switching processing, they then convert back to optical signals and send them to another optical fiber. Since the photoelectric conversion rate is low and there is a physical bottleneck in the processing speed of the circuit, people hope to design an "optical switch" that does not require photoelectric conversion. The internal part is not a circuit but an optical path, and the logic element is not a switching circuit but a It is the switch light path. This will greatly increase the processing rate of the switch.

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