What Is an Ethernet Port?

Ethernet (Ethernet) is currently the most widely used LAN communication method, and it is also a protocol. The Ethernet interface is the port for network data connection.

The following describes several common types of Ethernet interfaces.

SC Ethernet interface SC fiber interface

SC fiber optic interface has been applied in the 100Base-TX Ethernet era, so it was called 100Base-FX (F is the abbreviation of fiber for fiber), but because the performance was not more prominent than the twisted pair at the time, the cost was higher It has not been popularized. Now the industry is vigorously promoting gigabit networks, and SC fiber interfaces have been re-emphasized.

There are many types of optical fiber interfaces. SC optical fiber interfaces are mainly used in LAN switching environments. This interface is provided on some high-performance Ethernet switches and routers. It looks similar to the RJ-45 interface, but the SC interface is more flat. The obvious difference is the contacts inside. If it is 8 thin copper contacts, it is an RJ-45 interface. If it is a copper pillar, it is an SC fiber optic interface. ^[2]

RJ-45 Ethernet interface RJ-45 interface

This interface is our most common network equipment interface now, commonly known as "crystal head", and the technical term 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, and a plastic spring piece is fitted with the RJ-45 slot to prevent it from falling off. This interface can be used in 10Base-T Ethernet, 100Base-TX Ethernet, and 1000Base-TX Ethernet. The transmission medium is twisted pair, but there are different requirements for the medium depending on the bandwidth, especially 1000Base- When TX Gigabit Ethernet is connected, at least Super Category 5 cables must be used, and Category 6 cables must be used to ensure stable and high speed ^[2] .

FDDI Ethernet interface FDDI interface

FDDI is one of the most mature LAN technologies at present. It has the characteristics of a timing token protocol, supports a variety of topologies, and uses a fiber optic transmission medium. Optical Fiber Distributed Data Interface (FDDI) is a set of protocols for sending digital signals on optical cables by the American National Standards Institute (ANSI). FDDI uses a double-ring token, and the transmission rate can reach 100Mbps. CCDI is a variant of FDDI. It uses twisted-pair copper cable as the transmission medium, and the data transmission rate is usually 100Mbps. FDDI-2 is an FDDI extended protocol that supports voice, video and data transmission. It is another variant of FDDI, called FDDI Full Duplex Technology (FFDT). It uses the same network structure as FDDI, but the transmission rate can reach 200Mbps .

Because the use of optical fiber as a transmission medium has many advantages such as large capacity, long transmission distance, and strong anti-interference ability, it is often used in metropolitan area networks, campus backbone networks, and multi-building network distribution environments. Therefore, FDDI interfaces are used in network backbone switches. It is relatively common, and now with the popularization of Gigabit, some high-end Gigabit switches have begun to use this interface ^[2] .

AUI Ethernet interface AUI interface

The AUI interface is specifically used to connect thick coaxial cables. Earlier NICs had such interfaces connected to hubs and switches to form a network, which is generally not used now. The AUI interface is a "D" 15-pin interface. It was previously used in a token ring network or a bus network. It can be connected to a 10Base-T Ethernet network with the help of an external transceiver (AUI-to-RJ-45). Connection ^[2] .

BNC Ethernet interface BNC interface

BNC is an interface specifically used to connect with thin coaxial cables. Thin coaxial cables are also often referred to as "thin cables". Its most common application is the discrete display signal interface, which uses red, green, blue, and horizontal 2. The vertical scanning frequency is separately input to the interface of the display, and the interference between the signals is smaller. Now BNC is basically no longer used in switches, only a few early RJ-45 Ethernet switches and hubs also provide a few BNC interfaces ^[2] .

Console Ethernet interface Console interface

Ethernet switches that can be used for network management generally have a "Console" port, which is used to configure and manage 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 other methods of configuration often require the help of an IP address, domain name, or device name, and it is obviously impossible for a newly purchased switch to have these parameters built-in, the Console port is the most common and basic switch management and configuration port.

Different types of switches have different console ports. Some are on the front panel, and some are on the rear panel. Modular switches are usually located on the front panel, while fixed-configuration switches are mostly located on the rear panel. Above or to the side of the port, there will be a sign similar to "CONSOLE". In addition to different locations, the type of Console port is also different. Most switches use RJ-45 ports, but there are a few that use DB-9 serial ports or DB-25 serial ports. Regardless of whether the Ethernet switch uses the DB-9 or DB-25 serial interface or the RJ-45 interface, it needs to be connected to the serial port of the configurator's computer through a special Console cable.

Corresponding to the different console ports of the Ethernet switch, there are two types of console cables: one is a serial cable, that is, both ends are serial interfaces (both ends are female), and both ends can be plugged into the computer respectively Serial port and Console port of the switch; the other is a flat cable with RJ-45 connectors (RJ-45toRJ-45) at both ends.

Because both ends of the flat cable have RJ-45 interfaces, they cannot be directly connected to the computer serial port. Therefore, you must also use an RJ-45toDB-9 (or RJ-45to DB-25) adapter at the same time. Under normal circumstances, such a console cable and the corresponding DB-9 or DB-25 adapter will be given away randomly in the box of the switch ^[2] .