IEEE 802.3

IEEE 802.3
Name	IEEE 802.3
Title	Standard for Ethernet
Status	Published
Year started	1983
Organization	Institute of Electrical and Electronics Engineers
Committee	IEEE 802
Related standards	IEEE 802.1, IEEE 802.11
Domain	LAN technology

IEEE 802.3. It is a collection of technical standards defining the physical layer and data link layer's media access control for wired Ethernet networks. Developed and maintained by the Institute of Electrical and Electronics Engineers through its IEEE 802 working group, it forms the foundational basis for most wired local area network connectivity. Since its initial standardization in the 1980s, it has evolved dramatically, driving the proliferation of Internet access and enterprise networking worldwide.

Overview

The project began from research at Xerox PARC and was later developed into a commercially viable system by a consortium including Digital Equipment Corporation, Intel, and Xerox. The standard precisely defines how data is formatted for transmission and how devices on a shared medium contend for access, using a method called Carrier-sense multiple access with collision detection. This work is coordinated under the auspices of the IEEE Standards Association, with ongoing amendments managed by the IEEE 802.3 Ethernet Working Group. Its specifications ensure interoperability between networking equipment from vendors like Cisco Systems, Juniper Networks, and Hewlett Packard Enterprise.

Physical layer specifications

This standard encompasses a vast array of physical media specifications, each denoted by a nomenclature like "10BASE-T" or "1000BASE-SX". Early versions used coaxial cable, such as those defined in the original 10BASE5 and 10BASE2 standards. The transition to twisted-pair copper, exemplified by 10BASE-T, revolutionized office cabling. For higher speeds and longer distances, fiber optic variants were introduced, including 100BASE-FX, 1000BASE-LX, and 10GBASE-SR. Modern iterations, such as those for Data centers, support speeds of 400 gigabits per second over fiber, with specifications like 400GBASE-DR4 being ratified. Power delivery for devices like VoIP phones is standardized separately as IEEE 802.3af.

Frame format

The fundamental unit of transmission is the Ethernet frame, which encapsulates payload data from upper-layer protocols like the Internet Protocol. A frame begins with a Preamble (telecommunications) and Start frame delimiter, followed by destination and source MAC addresses. The middle section carries the payload and a Frame check sequence for error detection. The standard originally defined the EtherType field to identify the protocol, a method later supplemented by the IEEE 802.1Q tag for VLAN traffic. This structure is crucial for devices such as switches manufactured by Arista Networks and Broadcom to correctly forward traffic.

Evolution and versions

The first standard was published in 1983, formalizing the 10 Mbps system. A major leap occurred with the ratification of Fast Ethernet (100 Mbps) in 1995, followed swiftly by Gigabit Ethernet in 1999. The 2000s saw the rise of 10 Gigabit Ethernet, which found early adoption in backbone networks and the SAN market. Subsequent amendments have pushed speeds to 40 Gbps, 100 Gbps, and most recently 400 Gbps, with ongoing work targeting 800 Gbps and 1.6 Tbps. Key enabling technologies throughout this evolution include Autonegotiation, defined in the 1990s, and energy-efficient features like Energy-Efficient Ethernet.

Relationship to other standards

It operates within a broader ecosystem of IEEE 802 standards. The IEEE 802.1 working group handles higher-level bridging, management, and protocols like the Spanning Tree Protocol. While it governs wired media, wireless local networking is the domain of IEEE 802.11 (Wi-Fi). For metropolitan area networks, IEEE 802.17 defines Resilient Packet Ring technology. Its frames are often carried over wider Synchronous Optical Networking networks, and it interfaces with protocols defined by the Internet Engineering Task Force. The standard also references specifications from bodies like the Telecommunications Industry Association for cabling.

Applications and impact

It is the ubiquitous technology underpinning wired connections in enterprise networks, Data centers, and home Broadband routers. Its variants enable high-speed connections for High-performance computing clusters and financial trading systems like those on Wall Street. The development of Power over Ethernet standards, such as IEEE 802.3at, has powered devices from Security cameras to Wireless access points. Its reliability and scalability have made it the transport of choice for critical infrastructure, supporting everything from Industrial Ethernet on factory floors to backhaul for 5G networks deployed by Verizon Communications and AT&T.

Category:IEEE standards Category:Ethernet Category:Network protocols