What is an Ethernet adapter?

Ethernet is a baseband LAN technology developed in the 1970s. It uses coaxial cables as network media, adopts Carrier Multiple Access and Collision Detection (CSMA/CD) mechanism, and has a data transmission rate of Reach 10MBPS.

But nowadays Ethernet is more commonly used to refer to various local area networks using CSMA/CD technology. The frame format of Ethernet is consistent with IP and is particularly suitable for transmitting IP data. Ethernet is simple and convenient, low in price, and high in speed.

Previously, the physics community believed that there was an extremely sparse medium in the universe and called it ether, but later experiments proved that there was no so-called ether, because the word was a product of that time, just like our previous Many unscientific namings were caused by people before they were discovered. Although they were later proven to be incorrect, the names were passed down for commemoration or other reasons. Extended information

The original Ethernet used coaxial cables to connect various devices. The computer connects to the cable through a transceiver called the Attachment Unit Interface (AUI).

A simple network cable is still very reliable for a small network. For a large network, a fault in a certain line or a fault in a connector will cause one or more Ethernet problems. The network segment is unstable.

Because all communication signals are transmitted on private lines, even if the information is only sent to one of the terminals (destination), the message sent by a certain computer will be received by all other computers.

Under normal circumstances, the network interface card will filter out information that is not sent to itself, and will issue an interrupt request to the CPU only when the received destination address is its own information, unless the network card is in promiscuous mode (Promiscuous mode) .

This "one speaks, everyone listens" characteristic is the security weakness of shared-medium Ethernet, because a node on the Ethernet can choose whether to monitor all information transmitted on the line. Free access to the cable also means free access to the bandwidth, so Ethernet can be very slow in certain situations, such as after a power failure when all network terminals are restarted.

Baidu Encyclopedia--Ethernet