IEEE 802.3

Physical connections are made between network nodes and, usually, various network infrastructure devices (hubs, switches, routers) by various types of copper cables or optical fiber.

802.3 standards support the IEEE 802.1 network architecture.

802.3 also defines a LAN medium access control method using carrier-sense multiple access with collision detection (CSMA/CD).

Communication standards

The IEEE 802 Local and Metropolitan Area Networks Committee was formed in 1980 to create a single standard for the lower layers of a local or metropolitan area network. At the time, there were three approaches to local area networking: IBM’s token ring, the DEC-Intel-Xerox Ethernet, and the token bus. Because the group could not agree on a single approach, three working groups were formed, 802.3 for Ethernet (called CSMA/CD), 802.4 for token bus, and 802.5 for token ring. An Ethernet network had already been implemented at Xerox Parc to connect Alto computers to a laser printer in 1973. In 1980, Digital, Intel, and Xerox published a standard called the DIX standard. In 1982, they published a second version. The first IEEE Standard for the CSMA/CD approach was based on the DIX standard. The original IEEE standard for Ethernet was named "IEEE Standards for Local Area Networks: Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications” and subsequent standards were named similarly, until 2012 when it became simply “Standard for Ethernet”. This was because of sensitivities around using a commercial product as the basis for a standard.