What does Ethernet mean?

Ethernet is a computer local area network technology. The IEEE 802.3 standard of IEEE organization sets the technical standard of Ethernet, which includes physical layer wiring, electronic signal and medium access layer protocol. Ethernet is the most widely used LAN technology at present, which has replaced other LAN standards such as Token Ring, FDDI and ARCNET.

Ethernet realizes the idea that multiple nodes of the radio system on the network send information, and each node must obtain cables or channels to transmit information, sometimes called Ethernet.

The name comes from/kloc-optical ether, an electromagnetic radiation medium assumed by physicists in the 9th century. Later research proved that optical ether did not exist. Each node has a unique 48-bit address in the world, that is, the MAC address assigned by the manufacturer to the network card to ensure that all nodes on the Ethernet can authenticate each other. Because Ethernet is very common, many manufacturers directly integrate Ethernet cards into computer motherboards.

The standard topology of Ethernet is bus topology, but the current fast Ethernet (100BASE-T,100base-t standard) uses switching hubs for network connection and organization, so as to reduce conflicts and maximize network speed and efficiency.

In this way, the topology of Ethernet becomes a star; But logically, Ethernet still uses CSMA/CD (Carrier Sense Multiple Access/Collision Detection) bus topology and bus technology.

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history

Ethernet technology originated from the pioneering technical project of Xerox Palo Alto Research Center. People usually think that Ethernet was invented in 1973, when bob metcalfe wrote a memo to his PARC boss about the potential of Ethernet. But Metcalfe himself thinks that Ethernet didn't appear until several years later.

1976, Metcalfe and his assistant David Boggs published an article entitled "Ethernet: Distributed Packet Switching Technology in Regional Computer Networks".

Metcalfe once joked that Jerry Salz contributed to the success of 3Com. In an influential paper co-authored with others, Saltzer pointed out that token ring network is superior to Ethernet in theory.

Affected by this conclusion, many computer manufacturers either hesitate or decide not to use Ethernet interface as the standard configuration of machines, so that 3Com can make a fortune by selling Ethernet cards. This situation has also led to another saying that "Ethernet is not suitable for theoretical research, but only suitable for practical application".

Maybe this is just a joke, but it illustrates a technical point: usually, the actual data flow characteristics in the network are different from those estimated before the popularization of LAN, and it is precisely because of the simple structure of Ethernet that LAN is popularized.

Metcalfe and Saltzer used to work on the same floor of the Massachusetts Institute of Technology (MIT) MAC project, when he was doing his graduation thesis at Harvard University, during which he laid the theoretical foundation of Ethernet technology.

1979, Metcalfe left Xerox to set up 3Com in order to develop personal computers and local area networks. 3Com lobbied DEC, Intel and Xerox, hoping to realize the standardization and normalization of Ethernet with them.

This universal Ethernet standard was put forward by 1980 on September 30th. At that time, there were two popular non-public network standards, token ring network and ARCNET, which were rapidly shrunk and replaced by the impact of the Ethernet wave. In the process, 3Com also became an international company.