Ethernet interface introduction

Ethernet literacy , It mainly introduces the interface .

---

One 、 Introduction to Ethernet

         Ethernet is a computer LAN technology .IEEE The organization's IEEE 802.3 The standard establishes the technical standard of Ethernet , It specifies the connection including the physical layer 、 Contents of electronic signal and media access layer protocol . Ethernet is the most widely used LAN technology , It replaces other LAN technologies such as token ring 、FDDI and ARCNET.

Classic Ethernet ：

Winding around the building with a long cable , This cable connects all the computers .

Switched Ethernet ：

A device called a switch is used to connect different computers

Two 、 network card

network card (Network Interface Card, abbreviation NIC), Also known as network adapter , It is a device that connects computers and local area networks

A network card mainly includes OSI The bottom two floors of , Physical layer and data link layer

1、 The physical layer defines the electrical and optical signals needed for data transmission and reception 、 Line status 、 Clock reference 、 Data coding and circuits, etc , And provide standard interface for data link layer equipment . The chip in the physical layer is called PHY

2、 The data link layer provides addressing mechanism 、 Data frame construction 、 Data error checking 、 Transmission control 、 Provide standard data interface and other functions to the network layer . The chip of the data link layer is called MAC controller

      PHY Integrated a large number of analog hardware , and MAC It is a typical all digital device , Chip area and simulation / Why did the digital hybrid architecture first MAC Integrated into the microcontroller PHY The reason for staying out of the film . More flexible 、 Higher density chip technology can already be realized MAC and PHY Single chip integration

3、 ... and 、 Ethernet Interface

SC Fiber optic interface

        SC Optical fiber interface is mainly used in LAN switching environment , This interface is provided on some high-performance Ethernet switches and routers , It is associated with RJ-45 The interface looks very similar , however SC The interface looks more flat , The obvious difference is the inner contact , If it is 8 Thin copper contact piece , It is RJ-45 Interface , If it is a copper pillar, it is SC Fiber optic interface

RJ-45 Interface

         This interface is our most common network device interface , Be commonly called “ Crystal head ”, The technical term is RJ-45 The connector , It belongs to twisted pair Ethernet interface type .RJ-45 The plug can only be inserted in a fixed direction , There is a plastic shrapnel and RJ-45 The slot is stuck to prevent it from falling off . This interface is 10Base-T Ethernet 、100Base-TX Ethernet 、1000Base-TX Can be used in Ethernet , The transmission medium is twisted pair , However, there are different requirements for media according to the bandwidth , especially 1000Base-TX Gigabit Ethernet connection , Use at least Cat 5 lines , To ensure stability and high speed, it is necessary to use 6 Quasilinear

FDDI Interface

         Fiber distributed data interface （FDDI） By the American National Organization for Standardization （ANSI） A set of protocols for transmitting digital signals on optical cables .FDDI Interfaces are common on network backbone switches , With the popularity of Gigabit , Some high-end Gigabit switches have also begun to use this interface

AUI Interface

        AUI The interface is specially used for connecting thick coaxial cables , Early network cards had such interfaces and hubs 、 Switches are connected to form a network , Generally, I can't use it .AUI Interface is a kind of “D” type 15 Needle interface , Previously used in token ring network or bus network , With the help of external transceiver （AUI-to-RJ-45）, Realization and 10Base-T Ethernet connection

BNC Interface

        BNC It is specially used for connecting with thin coaxial cable , Thin coaxial cable is what we often say “ Thin cable ”, Its most common application is the separate display signal interface , That is, red 、 green 、 Blue and horizontal 、 The vertical scanning frequency is input into the interface of the display separately , The interference between signals is less .BNC Basically, it is no longer used in switches , Only some early RJ-45 A few are also available in Ethernet switches and hubs BNC Interface

Console Interface

         Ethernet switches that can manage networks usually have one “Console” port , It is specially used to configure and manage switches . adopt Console Connect ports and configure switches , It is a necessary step to configure and manage the switch

Four 、MII、RMII、GMII、RGMII Interface

        MII： 100M Ethernet interface , Single edge sampling .

        RMII： 100M Ethernet interface ,MII Simplified version of the line , Double edge sampling .

        GMII： Gigabit Ethernet Interface , Single edge sampling .

        RGMII： Gigabit Ethernet Interface ,GMII Simplified version of the line , Double edge sampling .

MII

        （Media Independent interface） Media independent interface , It is IEEE-802.3 Defined industry standards , yes MAC And PHY Interface between .MII The data interface contains 16 A signal and 2 A management interface signal  

RMII

        RMII(Reduced Media Independant Interface), Streamlining MII Interface , Save half the data cable .RMII Send and receive using 2 Bit data for transmission , The receiving and transmitting clocks all adopt 50MHz Clock source

GMII

GMII（Gigabit Media Independant Interface）, Gigabit MII Interface .GMII use 8 Bit interface data , Working clock 125MHz, So the transmission rate can reach 1000Mbps. Compatible with MII Required 10/100 Mbps Operation mode .GMII Interface data structure conforms to IEEE Ethernet standard , The interface is defined in IEEE 802.3-2000. The signal is defined as follows ：

RGMII

RGMII(Reduced Gigabit Media Independant Interface), Streamlining GMII Interface . be relative to GMII comparison ,RGMII Has the following characteristics ：

         send out / The receiving data line is provided by 8 Change article to 4 strip

        TX_ER and TX_EN Reuse , adopt TX_CTL delivery

        RX_ER And RX_DV Reuse , adopt RX_CTL delivery

        1 Gbit/s At a rate , The clock frequency is 125MHz

        100 Mbit/s At a rate , The clock frequency is 25MHz

        10 Mbit/s At a rate , The clock frequency is 2.5MHz

---

************************************************ Picture from the Internet , Please contact to delete the infringement **************************