What are the Ethernet switch interfaces?

An Ethernet switch is a switch that transmits data based on Ethernet, and Ethernet uses a LAN that shares a bus-type transmission medium. With the rapid development of computers and their interconnection technologies (also commonly referred to as "network technologies"), Ethernet has become a short-distance two-layer computer network with high penetration rate to date, and the core component of Ethernet is Ethernet switches.

Ethernet switches have an important assumption in design thinking that switching cores is very fast, and usually large traffic data does not cause congestion. In other words, the ability to exchange is infinite relative to the amount of information transmitted. Although the Ethernet Layer 2 switch is based on the development of multi-port bridges, after all, switching has its richer features, which not only provides a better way to get more bandwidth, but also makes the network easier to manage.

Ethernet switches are widely used, the price is relatively cheap, the categories are complete, and the application fields are very wide. They can be seen in all kinds of LANs. Ethernet switches usually have several to dozens of ports, which is essentially a multi-port bridge. In addition, its port rate can be different, and the working mode can also be different, such as providing 100M, 1000M bandwidth, providing half-duplex, full-duplex, and adaptive working mode.

Let's talk about what types of interfaces are available for Ethernet switches:

First, FDDI interface

FDDI is a high-speed transmission rate in the mature LAN technology. It has the characteristics of a timing token protocol and supports multiple topologies. The transmission medium is optical fiber.

The Fiber Distributed Data Interface (FDDI) is a set of protocols developed by the American National Standards Institute (ANSI) to transmit digital signals over fiber optic cables. FDDI uses dual-ring tokens and can transmit at 100Mbps.

CCDI is a variant of FDDI that uses twisted-pair copper as the transmission medium and typically has a data transfer rate of 100 Mbps.

FDDI-2 is an extended protocol of FDDI that supports voice, video and data transmission. It is another variant of FDDI, called FDDI full-duplex technology (FFDT), which uses the same network structure as FDDI, but the transmission rate can reach 200Mbps. .

Because the use of optical fiber as the transmission medium has many advantages such as large capacity, long transmission distance, strong anti-interference ability, etc., it is often used in the environment of metro network, campus environment backbone network and multi-building network distribution, so FDDI interface is in the network backbone switch. It is more common, and now with the popularity of Gigabit, some high-end Gigabit switches also use this interface.

Second, SC fiber interface

The SC fiber interface has been used in the 100Base-TX Ethernet era, so it was called 100Base-FX (F is the abbreviation of fiber word fiber), but at that time, because the performance is not more prominent than the twisted pair, but the cost is higher, so Not popularized, the industry is now promoting Gigabit networks, and SC fiber interfaces are re-emphasizing.

There are many types of fiber interfaces. The SC fiber interface is mainly used in the office network switching environment. It is provided on some high-performance Gigabit switches and routers. It looks similar to the RJ-45 interface, but the SC interface is more flat. The obvious difference is the contact inside. If it is 8 thin copper contacts, it is the RJ-45 interface. If it is a copper column, it is the SC fiber interface.

Third, RJ-45 interface

This kind of interface is our common network device interface, commonly known as "Crystal Head", the terminology is RJ-45 connector, which belongs to the twisted pair Ethernet interface type. The RJ-45 plug can only be inserted in a fixed direction, with a plastic dome attached to the RJ-45 slot to prevent it from falling out.

This interface can be used in 10Base-T Ethernet, 100Base-TX Ethernet, 1000Base-TX Ethernet, and the transmission medium is twisted pair. However, depending on the bandwidth, the medium also has different requirements, especially 1000Base- When connecting to a Gigabit Ethernet connection, use at least a Category 5 cable. To ensure stable high speed, use Category 6 cable.

Fourth, AUI interface

The AUI interface is specially used to connect thick coaxial cables. On the early network cards, such interfaces were connected to hubs and switches to form a network, which is generally not used now.

The AUI interface is a "D" type 15-pin interface. It was previously used in a Token Ring or Bus type network. It can be connected to a 10Base-T Ethernet network by means of an external transceiver (AUI-to-RJ-45). Connection.

Five, Console interface

A switch that can be network managed generally has a "Console" port that is dedicated to configuring and managing the switch. Connecting and configuring the switch through the console port is a step that must be taken to configure and manage the switch. Because the configuration of other methods often needs to be implemented by means of IP address, domain name or device name, it is obviously impossible for the newly purchased switch to have these parameters built in, so the console port is a common basic switch management and configuration port.

Different types of switch console ports are located at different locations, some on the front panel and some on the rear panel. Usually modular switches are mostly located on the front panel, while fixed configuration switches are mostly located on the rear panel. There will be an identifier like "CONSOLE" on the top or side of the port.

Sixth, BNC interface

BNC is an interface specially designed for connection with thin coaxial cable. Thin coaxial cable is also known as "thin cable". Its common application is separate display signal interface, which is red, green, blue and horizontal. The vertical scanning frequency is input to the interface of the display separately, and the interference between the signals is smaller.

BNC is now no longer used in switches, and only a few BNC interfaces are available in some of the early RJ-45 Ethernet switches and hubs.