Definition

The earliest Ethernet standard was the DEC-Intel-Xerox (DIX) standard jointly developed by the Digital Equipment Corporation (DEC), Intel, and Xerox in 1982. After years of development, Ethernet has become the most widely used local area network (LAN) type, and many Ethernet standards have been put into use, including standard Ethernet (10 Mbit/s), fast Ethernet (100 Mbit/s), gigabit Ethernet (1000 Mbit/s), and 10G Ethernet (10 Gbit/s). IEEE 802.3 was defined based on Ethernet and is compatible with Ethernet standards.

In the TCP/IP suite, the IP packet encapsulation format on an Ethernet network is defined in RFC 894, and the IP packet encapsulation format on an IEEE 802.3 network is defined in RFC 1042. Currently, the format defined in RFC 894 is most commonly used. This format is called Ethernet_II or Ethernet DIX.

To distinguish Ethernet frames of the two types, Ethernet frames defined in RFC 894 are called Ethernet_II frames and Ethernet frames defined in RFC 1042 IEEE 802.3 are called frames in this document.

History

In 1972, when Robert Metcalfe (father of Ethernet) was hired by Xerox, his first job was to connect computers in Xerox's Palo Alto Research Center (PARC) to the Advanced Research Projects Agency Network (ARPANET), progenitor of the Internet. In 1972 also, Robert Metcalfe designed a network to connect computers in the PARC. That network was based on the Aloha system (a radio network system) and connected many computers in the PARC, so Metcalfe originally named the network Alto Aloha network. The Alto Aloha network started operating in May 1973, and Metcalfe then gave it an official name Ethernet, which is the prototype of Ethernet. The network operated at a rate of 2.94 Mbit/s and used thick coaxial cable as transmission medium. In June 1976, Metcalfe and his assistant David Boggs published a paper Ethernet Distributed Packet Switching for Local Computer Networks. At the end of 1977, Metcalfe and his three co-workers were gained a patent on "Multipoint data communication system with collision detection." Since then, Ethernet was known to the public.

As Ethernet technology develops rapidly, Ethernet has become the most widely used LAN technology and replaced most of other LAN standards, such as token ring, fiber distributed data interface (FDDI), and attached resource computer network (ARCNET). After rapid development of 100M Ethernet in the 20th century, gigabit Ethernet and even 10G Ethernet are now expanding their applications as promoted by international standardization organizations and industry-leading enterprises.

Purpose

Ethernet is a universal communication protocol standard used for local area networks (LANs). This standard defines the cable type and signal processing method used for LANs.

Ethernet networks are broadcast networks established based on the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) mechanism. Collisions restrict Ethernet performance. Early Ethernet devices such as hubs work at the physical layer, and cannot confine collisions to a particular scope. This restricts network performance improvement. Working at the data link layer, switches are able to confine collisions to a particular scope. Switches help improve Ethernet performance and have replaced hubs as mainstream Ethernet devices. However, switches do not restrict broadcast traffic on the Ethernet. This affects Ethernet performance. Dividing a LAN into virtual local area networks (VLANs) on switches or using Layer 3 switches can solve this problem.

As a simple, cost-effective, and easy-to-implement LAN technology, Ethernet has become the mainstream in the industry. Gigabit Ethernet and even 10G Ethernet make Ethernet the most promising network technology.