8023

IEEE 802.3, commonly associated with Ethernet, is a family of standards defining the physical layer and the Media Access Control (MAC) sublayer for Ethernet local area networks (LANs) and certain metropolitan networks. It is maintained by the IEEE 802.3 Working Group under the IEEE 802 LAN/MAN Standards Committee and covers data transmission over a range of media, including copper twisted pair and optical fiber, across multiple data rates.

The standard originated in 1983 to standardize Ethernet over coaxial cables and introduced media access control through CSMA/CD for shared networks. Since then, the 802.3 family has evolved to support speeds from 10 Mbps to multi-gigabit and beyond, including Fast Ethernet (100 Mbps), Gigabit Ethernet (1 Gbps), and 10 Gigabit Ethernet, across various media. The 2018 revision of 802.3 consolidates numerous amendments and continues to be expanded by new amendments addressing additional speeds and media types.

Technically, 802.3 specifies the MAC addressing scheme, frame formats, error detection through cyclic redundancy check (CRC), and the physical layer specifications for a variety of media. While CSMA/CD is foundational in legacy half-duplex Ethernet, modern Ethernet networks predominantly operate in full duplex through switches, reducing collision domains and increasing efficiency.

Notable extensions within the 802.3 family include the various Ethernet speeds over copper and fiber, such as 10BASE-T, 100BASE-TX, 1000BASE-T, and 10GBASE-T, as well as Power over Ethernet (PoE) provisions, including 802.3af, 802.3at, and 802.3bt, which supply electrical power over Ethernet cabling for compatible devices.